Utilization of Food Wastes for Sustainable Development

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UtilizationoffoodwastesforsustainabledevelopmentARTICLEinELECTRONICJOURNALOFENVIRONMENTAL,AGRICULTURALANDFOODCHEMISTRYJANUARY2009

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UTILIZATION OF FOOD WASTES FOR SUSTAINABLE

DEVELOPMENT Iheanyi Omezuruike Okonko1*, 2Ogunnusi, Tolulope Adeola, 3Fajobi Enobong Aloysius, 4Adejoye, Oluseyi

Damilola and 3Ogunjobi Adeniyi Adewale 1Department of Virology, Faculty of Basic Medical Sciences, College of Medicine, University College

Hospital (UCH), University of Ibadan, Ibadan, Nigeria. 2Department of Basic Sciences, Federal College of Wildlife Management, New Bussa, Niger State,

3Enviromental Microbiology and Biotechnology Unit, Department of Botany and Microbiology, University of Ibadan, Ibadan, Nigeria.

4Department of Biology, Tai Solarin University of Education, Ijebu-Ode, Ogun State, Nigeria * [email protected]

ABSTRACT This review article deals with the alternative means of handling food wastes including the conversion of wastes from gari industry, cassava peels, shaft from processed cassava, yam, plaintain, banana agro-waste, corncobs, citrus, pastures and sugar cane, forage, organic wastes etc. into useful products for human and animal consumption in Nigeria. The biconversion of waste to useable energy is also a part of utilization of waste, as by burning solid fuel for heat, by fermenting plant matter to produce fuel, as ethanol, or by bacterial decomposition of organic waste to produce methanol. Alternative means of handling food wastes focus more on utilization rather than disposal. Thus, the possibility of producing a useful product from wastes will greatly ehnance and ensure sustainable economic development in Nigeria and the world at large. KEYWORDS Conversion, quality, product development, sustainable development, wastes utilization.

Okonko et al. EJEAFChe, 8 (4), 2009. [263-286]

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INTRODUCTION More recently the problem of effluent from processing operation and their disposal has gained public recognition. In many areas of the world, especially the developing countries, the environmental issues are the same (Okonko et al., 2006; Shittu et al., 2007). Human beings produce large quantities of wastes as we go about our daily lives. From our homes come wastes from food preparation, washing machines, baths, toilets, newspapers, junk mail, packaging, hobbies, auto and home maintenance projects, and the landscape. In addition, wastes are generated in producing the goods and services we utilize.

Waste is defined as any material, which has not yet been fully utilized, i.e. the leftovers from production and consumption. However, waste is an expensive and sometimes unavoidable result of human activity. It includes plant materials; agricultural, industrial, and municipal wastes and residues. Waste also refers to liquid or solid discharged from residences, business premises, small scale industries, and institutions. In general, waste can be characterized based on its bulk or organic contents, physical characteristics, and specific contaminants (Okonko et al., 2006). According to Okonko et al. (2006), each waste contains its unique quality and characteristics, which then suggests the type of treatment required. The two divisions of waste Domestic and Industrial effluent have different make-ups and often require various treatment processes. Though, waste treatment is generally classified into four levels: primary, secondary, tertiary, and quaternary treatment with each treatment level aimed at removing a more specific class of contaminants (Mc Langhlin, 1992; Aririatu et al., 1999; Okonko et al., 2006). MATERIALS AND METHODS SUSTAINABLE DEVELOPMENT

Sustainable development is a process in which the exploitation of resources, the direction of investments, the orientation of technological development and the institutional changes are all made consistent with future as well as the present needs. Sustainable development helps achieve the necessary balance between the resolution of social and economic problems and the protection of the environment, the provision of desirable living conditions for the present generations and measures taken to preserve these conditions for future generations.

Sustainable development is also a key phrase used by politicians, economists and environmentalists. Sustainable advancement and development in relation to a nation is the process of making living, that area of land and/or water more useful or profitable for mankind. The life sickness affects over 30% of global socio-economic and sustainable development turnover by way of healthcare, food and energy, agriculture and forestry. This percentage impact will grow with biotechnological developments which are increasingly improving the efficiencies of production processes in all spheres of life. This therefore implies that biotechnology occupy a very strategic position in the socio-economic advancement and sustainable development of the nation in particular and the world at large. Scientific advances through the years have relied on the development of new tools to improve socio-economy such as health care, agricultural production, and environmental protection (Okonko et al., 2006).


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Sustainable development is a policy which aims to ensure that development meets the needs of our present society without compromising the ability of future generations to meet their own needs (Okonko et al., 2006). Sustainable development aims to ensure that the development needs of the present do not compromise the needs of future generations. A way of addressing this sensitive issue could be through the sustainable development of waste as an alternative and renewable energy resource. WASTE UTILIZATION

Wastes are produced by virtually all types of industries, although many cleanup and disposal options exist, no single process can be applied to all types of waste steams. The trend in the world today is to convert waste into useful products through the manipulation of microorganisms and to recycle waste product as much as possible and the role of microorganisms in waste utilization has been studied extensively by several authors. Some workers have thus explored ways of minimizing the environmental hazard posed by the gari industry effluent, not just by getting rid of it but by converting it to useful products. Waste utilization is another approach in waste management practice. Waste utilization is an ecologically safe and economically efficient method of waste management since; the waste is not treated spending money or disposed off in the landfill causing pollution. Waste utilization could be brought about by the following methods: Bioconversion

Biological processes for the conversion of wastes to fuels include ethanol fermentation by yeast or bacteria, and methane production by microbial consortia under anaerobic conditions. Bioconversion is referred to as the enzyme-mediated conversion of organic substrates, such as cellulose, to other more valuable substances, such as protein, by other organisms. The conversion of biomass to useable energy, as by burning solid fuel for heat, by fermenting plant matter to produce fuel, as ethanol, or by bacterial decomposition of organic waste to produce methanol is also referred to as bioconversion (Okonko et al., 2006). Bioremediation

One of the promising methods for toxic waste cleanup problems is bioremediation. Bioremediation is a environmental biotechnology process that use either naturally occurring or deliberately introduced microorganisms, to consume and breakdown environmental pollutants into harmless by-products such as water, CO2 and salts, in order to cleanup a polluted site. Naturally occurring bacteria or fungi that degrade specific substances are isolated, cloned, and manufactured in large quantities and introduced as combinations of microorganisms into a hazardous waste site to eliminate specific contaminants. Under carefully controlled conditions, it is a practical and cost effective method to remove pollutants from contaminated surfaces and subsurfaces. Biotechnological Processes

In the industry the production processes are now being modified using biotechnology for reduction in pollution caused by the conventional methods. The


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biotechnological processes also prove to be very economical and also they provide products, which are better or at least equal in quality to the conventional methods. But in these processes the cost of pollution eradication is also saved as these processes generally give out very little or nil pollution and are more efficient than the conventional processes. Biotechnology serves as a solution to many problems in various fields ranging from fuels to many other cleaner and innovative clean up technologies. Some examples are:

1. Biotechnological production of biosurfactants 2. Biochemical conversion of lignocelluloses substrates to cellulose, liquid glucose,

and value added chemicals. Biotechnological, bioremediation or bioconversion process is often successful and

the most inexpensive method, it is only one of many techniques for dealing with hazardous wastes. This biological waste treatment or bioconversion is desirable because it is inexpensive, can be done at the site of pollution, and causes minimal physical disturbance to the surrounding area compared to other methods (Okonko et al., 2006). Biocatalysis

To develop biocatalytic methods for the conversion of crop derived carbohydrates to high value polysaccharides or oligosaccharides. The project composed of two major objectives. Develop biocatalytic methods for the conversion of starch, corn coproducts, beet sugar, or cane sugar to value-added oligosaccharides. Biofilm reactors

Nicolella et al. (2000) reported that biofilm reactors are in operation at industrial scale throughout the world. Use of biofilm reactors is anticipated to be economical for the production of these industrial chemicals. It has been reported that the best biofilms were obtained with Pseudomonas fragi, Streptomyces viridosporus, and Thermoactinomyces vulgaris when used in combination with polypropylene composite chips. SOURCES AND NATURE OF FOOD WASTE FOR BIOPRODUCT DEVELOPMENTS

Waste contains three primary constituents: cellulose, hemicellulose and lignin, and can contain other compounds (e.g. extractives). Cellulose and hemicellulose are carbohydrates that can be broken down by enzymes, acids, or other compounds to simple sugars, and then fermented to produce ethanol renewable electricity, fuels, and biomass-based products (Puri, 1984; Wyman and Goodman, 1993; van Wyk, 2001). When the amount of organic agricultural waste, such as corn stalks, leaves and wheat straw from wheat-processing facilities, sawdust and other residues from wood mills, is also considered, this component of solid waste could be a principal resource for biodevelopment (Louwrier, 1998; van Wyk, 2001). Materials of organic origin are known as biomass (a term that describes energy materials that emanate from biological sources) and are of major importance to sustainable development because they are renewable as opposed to non-organic materials and fossil carbohydrates (van Wyk, 2001).

Common farm organic wastes such as maize cobs, banana peels, pawpaw fruit peels, maize chaff, stumps of palm tree, palm tree inflorescence, maize stem, rice straw and spinch weeds were earthworm (Eudrilus eugeniae) garden snail (Limicolaria aurora) and palm grub (Oryctes rhinoceros). It was demonstrated by Omoyinmi et al. (2004) that animal protein production varied from 0.91g/kg to 1.41g/kg of waste in earthworm, from 1.15g/kg to 1.40g/kg of waste in garden snail and from 0.90g/kg to 1.60g/kg of waste in


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palm grub. It was also shown that the short life cycle and production of large number of offsprings could be harnessed for the raising of feed for fish/livestock and in some cases human consumption. This culture of invertebrates offered economic benefits to the farmer and it improved on the environmental quality by transforming wastes into beneficial products.

A surveys on the potential for biomass waste to alleviate energy problems in Tanzania through utilization of agro-industrial residues for anaerobic conversion into biogas and biodiesel, sisal industry, the largest producer of agro-industrial residues, has a potential to produce energy that could greatly supplement the current shortfall of hydropower generation (Kivaisi and Rubindamayugi, 1996).

In 2004, Kareem and Akpan reported that the use of agricultural by-products as substrate for enzyme production was cheap and could facilitate large scale production of industrial enzymes in the tropics. Eight isolates of Rhizopus sp. was obtained from the environment and were grown on solid media for the production of pectinase enzymes. Three media formulated from agricultural materials were the following: medium A (Ricebran + Cassava Starch, 10:2w/w); Medium B (Cassava Starch + Soyabean, 1:2 w/w); Medium C (Ricebran + Soyabean + Casein hydrolysate, 10:20.5 w/w). The result obtained by Kareem and Akpan (2004) showed that medium A gave the highest pectinase activity of 1533.33u/ml followed by medium A and C with 1,366.66 and 1066.00/ml respectively after 72hrs fermentation. The three solid media supported profuse mycelial growth of Rhizopus species and enhanced its pectinase producing potential (Kareem and Akpan, 2004).

A comparative study of the performance of cow dung and poultry manure as alternative nutrient sources in a bioremediation process was described by Obire and Akinde (2005) and Chukwura et al. (2005). Obire and Akinde (2005) also reported that that amelioration of oil polluted soil with cow dung and poultry manure facilitates the disappearance of crude oil in the soil thereby increasing the rate of soil recovery. Poultry manure performed better than Cow dung which will greatly enhanced food productivity at such a time like this when the world at large is facing food crisis. Coffee-husk and Pulp Coffee husk and coffee pulp are coffee processing by-products. Some of the husk is used as organic fertilizer (Cabezas et al. 1987) while coffee pulp has its application and utilization in Swine feeding (Jarqun, 1987). The presence of tannins and caffeine diminishes acceptability and palatability of husk by animals. Caffeine Caffeine is also a component of several cola drinks. The addition of caffeine in cola drinks is responsible for almost 70% of the world's pure caffeine trading (Mazzafera, 2002; Mazzafera et al., 2002). Asano et al (1993) reported a successful microbial production of theobromine from caffeine while Braham and Bressani (1987) and Bressani and Braham (1987a,b) have reported the potential uses of coffee berry byproducts and the composition, technology, and utilization of coffee pulp in other species as well as its anti-physiological factors. The popularity of coffee beverage is also based on the stimulant effect of caffeine, because of this pharmacological effect; caffeine has long been added to medical formulations to compensate the depressive effects of other drugs (James, 1991).


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Citrus Pulp According to Wing (1975) and Wing et al (2003), the Florida Citrus Exchange established a fellowship for research into uses of citrus waste in 1911 and thus launched an area of investigation which remains strongly productive. Involved primarily is citrus pulp, consisting mainly of the rag, peel, and seeds of oranges with minor amounts from other fruits (Hendrickson and Kesterson, 1965). This waste collects on concrete slabs or in open pits at canneries. Cattle eat citrus pulp in the fresh state, but it accumulates too fast for current consumption, and it ferments and spoils too rapidly to save as it is produced. The feeding value and nutritive properties of citrus by-products proved that the digestible nutrients of dried grapefruit refuse were good for growing heifers (Neal et al., 1935). Citrus Molasses Citrus molasses also serves as a substrate for fermentation in the beverage-alcohol industry (Becker et al., 1946). The remaining distillery waste can be condensed to a very acceptable feedstuff high in pentose sugars and, because of yeast used for fermentation, high in good quality protein. Large and increasing amounts of citrus molasses are used for production of beverage alcohol. The remaining sugars, which are pentoses, cannot be used by the beverage industry, but they are an excellent source of energy for cattle. Cassava Wastes Disposal of agricultural byproducts such as cassava wastes from processing activities is becoming a concern in Nigeria due to its foul dour. Conversion of these low-value cassava wastes into biosorbent that can remove toxic and valuable metals from industrial wastewater would increase their market value and ultimately benefit the millions of cassava starch, garri and fufu producers. Cassava is a major staple food in Nigeria and therefore produces large volumes of wastes, which has been creating environmental nuisance in the region (Horsfall et al. 2003)

Cassava (Manihot esculenta Crantz), a major staple food in many tropical countries like Nigeria and therefore produces large volumes of wastes, which has been creating environmental nuisance in the region (Vlavonou, 1989). Disposal of agricultural byproducts such as cassava wastes from processing activities is becoming a concern in Nigeria due to its foul odour. Conversion of these low-value cassava wastes into biosorbent that can remove toxic and valuable metals from industrial wastewater would increase their market value and ultimately benefit the millions of cassava starch, garri and foofoo producers (Horsfall et al. 2003).

Cassava also has to be processed in various ways to reduce its cyanide content to safe levels for human consumption. One of the traditional forms into which the tuber is processed is a granular starchy product called gari. In the processing of gari, the cassava roots are peeled, washed, grated and dewatered with presses. It is sometimes allowed to ferment in the press bag for 1-4 days for flavour development. The dewatered meal is sieved to remove large fibres and roasted in large shallow open pots to get garri. The grating and dewatering are the most important unit processes vital for the detoxification of the product, though the roasting step also serves to volatize remnant HCN. Large volumes of starchy effluent are generated during the dewatering or pressing step as waste.


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In gari-producing communities, huge amounts of this effluent are generated and constitute an environmental menace. In Nigeria, high levels of gari effluent are produced daily and carelessly drained onto roads, streets, rivers and agricultural lands, thereby, constituting a serious environmental hazard. Not only does the effluent result in a strong stench, it could also result in loss of aquatic life because it is toxic. During the grating of cassava, cyanohydrins are produced at maceration by action of endogenous linamarase on the cyanogenic glucosides of cassava, linamarin and lotastrain. Being unstable above pH4 (effluent pH=4.3), these would degrade non-enzymatically to give free cyanide.

There is thus likely to be higher percentage of HCN than cyanohydrin in the effluent. It is expected that boiling to gelatinize the effluent starch would greatly reduce the HCN content by volatilization and during fermentation, more HCN would be lost as the broth is agitated by CO2 released. Also during distillation, if the distillate is collected only at the boiling point of alcohol, most of the residual HCN would be lost before ethanol collection. In this way, a distilled alcoholic beverage with acceptable cyanide content can be prepared from the effluent. The following therefore is a test of hypothesis and is a report of an attempt to prepare an alcoholic beverage fit for human consumption from gari industry effluent.

Uzochukwu et al. (2001) carried out an investigation into the possibility of producing a useful product from gari industry effluent, which is an environmental menace, using a fermentation process. The effluent starch with an initial HCN concentration of 9mg/ml was gelatinzed by cooking, hydrolyzed using commercial alpha and beta amylases and fermented with Saccharomyces cerevisiae from palm wine. The fermented broth was distilled in the presence of dry orange peel. HCN concentration in the final product was reduced by 99.9%, to a level that is safe for human consumption. Ethanol content was 50.1% (v/v). According to Uzochukwu et al. (2001), sensory evaluation showed that the product was moderately acceptable, though the ethanol yield was low. This showed that maximum starch conversion to fermentable sugars by the commercial alpha and beta amylases occurred at the 90th minutes with sugar concentration increasing from the initial 3% to 23% suggesting that any residual cyanide did not inhibit the amylses. They concluded that the environmentally undesirable gari effluent can be given economic value by being converted to portable spirit which can be employed for the preparation of various beverages and foods as well as pharmaceuticals for internal consumption. The process also detoxifies the final effluent, making it safe for discharge into streams and rivers.

Recently, Cassava starch powder produced locally from Nigerian Cassava Starch Paste was tested for its ability to serve as a solidifying agent in microbiological nutrient media by Dabai and Muhammed in 2004 using different aqueous percentage concentration in pour plate and slants. Ten percent (10%) concentration produced getting usually associated with solid nutrient media within 30 minutes, though cassava starch has not been observed to support microbial growth at the concentration used. In view of the findings of Dabai and Muhammed, (2004), Cassava starch powder can therefore be suggested as a potential solidifying agent in microbiological nutrient media as an alternative to Agar-agar. Pineapple Peels According to Tran et al. (1998) selection of a strain of Aspergillus for the production of citric acid from pineapple waste in solid-state fermentation proved valuable.


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Corn Cobs/Local Plant Tubers Corncobs is waste produced from an agricultural products, it was converted into fermentable sugars by the pretreatment processes of dilution with distilled water and the action of concentrated hydrochloric acid respectively (Ashiru, 2005). According to Ashiru (2005), the presence of these fermentable sugars i.e. hexose sugars and additional nutrients added to this substrate, were then utilized each by two yeasts, Candida albicans, Saccharomyces cerevisiae and a mould, Neurospora crassa and converted it into ethanol after incubation for 96 hours at a temperature of 37OC.

There has been preparation of several useful substances from corn cobs as far back as 1918 (LaForge and Hudson (1918). Growth culture media has also been composed from corn cobs and local plant turbers for microbial isolation as reported in a study by Bankole et al (2006). All media prepared from local plant tubers supported the growth fungi (Bankole and Aina, 2005). Corncob was also acid hydrolyzed by Ashiru (2005) to obtained glucose and pentose sugars. At the end of acid hydrolysis, corncob demonstrated to give high yield in hexose sugars with a brix degree of 26O. Sugarcane bagasse Sugarcane bagasse is also waste product generated in large quantities in Nigeria and is classified as lignocelluloses. It was acid hydrolyzed by Ashiru (2005) to obtained glucose and pentose sugars. At the end of acid hydrolysis, detoxification was carried out for all substrates using potassium hydroxide and this was followed by the addition of other nutrients to increase yield and facilitate better fermentation. The highest yield and productivity was recorded with the fungus Neurospora crassa using sugarcane bagasse with values being 77.88g1-1 (Ashiru, 2005). Sugar Cane Molasses There has been continuous production of citric acid from sugar cane molasses using a combination of submerged immobilized and surface stabilized cultures of Aspergillus niger, KCU520 as reported by Gupta (1994). Molasses are wastes products produced from sugar refineries and as an agricultural waste respectively, it was converted into fermentable sugars by the pretreatment processes of dilution with distilled water and the action of concentrated hydrochloric acid respectively. The presence of these fermentable sugars i.e. hexose sugars and additional nutrients added to these substrates, were then utilized each by two yeasts, Candida albicans, Saccharomyces cerevisiae and a mould, Neurospora crassa and converted into ethanol after incubation for 96 hours at a temperature of 37OC. Neurospora crassa produced the highest percentage yield of ethanol from the substrates, with 33.65% yield. Candida albicans produced the lowest percentage yield with 14.46% from molasses. Saccharomyces cerevisiae produced a percentage 23.59% ethanol from molasses (Ashiru, 2005). Yam tubers waste Two species each of Yam (Dioscorea rotundata) and (Dioscorea alata) which are local common plant tuber in Nigeria was sourced and used for the production of amala flour which is being consumed as staple food in Southwestern, Nigeria. Different species of yam has also been sourced and compared with Irish potato for the growth support capability for fungi (Aspergillus niger, Rhizopus nigicans and Saccharomyces cerevisiae) in a study by Bankole and Aina in 2004. The raw material was reported to have supported the growth of inoculated fungi with cooked yam by the 3rd day of growth.


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Cocoyam tubers Cocoyam (Colocesia esculenta) is an edible root crop belonging to the family Aracea. It makes significant contribution both as root crops and vegetables in the diet of people, particularly Nigerians and Africans at large. The percentage of starch (72%) in cocoyam was exploited in the production of ethanol and vinegar by Braide et al. (2005). This was achieved by two distinct biochemical processes brought about by the action of microorganisms under controlled environmental conditions. The first process called alcoholic fermentation was brought about by yeast (Saccharomyces carlsbergensisi) and the second process acetic acid fermentation (acetification) was brought about by an acetic acid bacteria (Acetobacter sp.). Saccharification of gelatinized mash undergo two (2) stages of enzyme hydrolysis, namely bacteria alpha-amylase (Amylic-TS) and fungal alpha-amylase (AGM) to produce fermentable sugars. Statistically, there exist a significant difference in the aroma and colour, but not in taste between cocoyam vinegar compared with commercial cider and white vinegar at 95% confidence limit. Soy Whey/Soybean Curd Residue Agarose-entraped Aspergillus niger cells has been used for the production of citric acid from soy whey (Khare, 1994). Soybean curd residue supplement has been found to be very significant for enhancement of methane production from pretreated woody waste (Take et al., 2005). Mango Peels The use of fermented and unfermented mango peels (Mangifera indica-R) as animal feeds was reported by Ojokoh (2005). Ripe mango peels (Mangifera indica-R) was naturally fermented for 96 hours at room temperature (30OC). The quality of the unfermented and fermented mango peels were accessed by determining the proximate composition, mineral contents, anti-nutritional content as well as the microbiological quality. The result of the proximate analysis revealed that there was an increase in the protein content of the ripe mango peels fermented with value of 8.64% contents. Ojokoh (2005) used the fermented and unfermented samples to feed albino rats and found that there was an increase in the daily weight of the albino rat feds with these mango peels. Banana Agro-Waste Banana is major cash crop of this region generating vast agricultural waste after harvest. The agro-waste including dried leaves and psuedostem after harvest was used as substrate for the release of sugars. Thus, under these conditions the agro-waste left behind for natural degradation can be utilized affectively to yield fermentable sugars which can be converted into other substances like alcohol (Baig et al., 2003). Processed Food Waste Food waste can be defined as any edible material or byproduct that is generated in the production, processing, transportation, distribution, or consumption of food. The primary waste products fed to swine are plate and kitchen waste, bakery waste, and food products from grocery stores and this has proved very valuable as reported by many authors (MWPS, 1993) and dehydrated restaurant food waste products are used as feedstuffs for finishing pigs (Myer et al., 1999). Biosolids Biosolids are nutrient-rich, predominantly organic materials. Although classified as a waste material, biosolids can be a beneficial agricultural or horticultural resource because they contain many essential plant nutrients and organic matter. Following proper


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treatment and processing, biosolids can be recycled as fertilizers or soil amendments to improve and maintain productive soils and stimulate plant growth, with negligible human health or environmental impacts (MWPS, 1993; Muchovej and Obreza, 2001; Obreza and O'Connor, 2003).

Decades of worldwide research have demonstrated that biosolids can be safely used on food crops. In 1996, the National Academy of Sciences (NRC 1996) reviewed current practices, public health concerns, and regulatory standards, and concluded that the use of these materials in the production of crops for human consumption when practiced in accordance with existing federal guidelines and regulations, present negligible risk to the consumer, to crop production, and to the environment. In addition, an epidemiological study of the health of farm families using biosolids showed that the use of biosolids was safe. A report issued by the National Academy of Sciences (NRC 2002) in 2002 found that there is no documented scientific evidence that this has failed to protect public health. However, additional scientific work is needed to reduce persistent uncertainty about the potential for adverse human health effects form exposure to biosolids (Muchovej and Obreza, 2001; Obreza and O'Connor, 2003). The Academy report also recommended that the US Environmental Protection Agency (USEPA) conduct another national sewage sludge survey to confirm the continuing reduction in biosolids metal concentrations, the negligible concentration of toxic organics previously identified as problematic, and to expand biosolids analysis to include compounds recently suggested as potentially troublesome (e.g. antibiotics, flame retardants, and endocrine-disruptors). Such a survey is welcomed by most people familiar with biosolids, as it will replace unbridled speculation with fact (MWPS, 1993; Muchovej and Obreza, 2001; Obreza and O'Connor, 2003; Roka et al., 2004). Lignocellulose as a Resource for Bioproducts Lignocellulose consists of lignin, hemicellulose and cellulose; Sun and Cheng (2002) shows the typical compositions of the three components in various lignocellulosic materials. Hydrolysis methods have also been used to degrade lignocellulose to alkaline (Chahal, 1992) and acid (Nguyen, 1999; Grethlein and Converse, 1991). However, many processes enzymes are preferred to acid or alkaline processes since they are specific biocatalysts, can operate under much milder reaction conditions, do not produce undesirable products and are environmentally friendly. The future of fermentation technology will be greatly enhanced by lignocellulose conversion (Dale, 1987). The findings of Okeke and Obi (1994, 1995) on the lignocellulose and sugar compositions of some agro wastes materials showed that saccharification of agro wastes materials by fungal cellulases and hemicellulases yielded high sugar content.

To develop the carbohydrate potential of biowaste materials, its cellulose content has to be converted into sugars such as glucose that can be used as starting compounds in the biosynthesis of many bioproducts. This conversion process could either be acid or enzyme catalyzed; the concentrated acid process for producing sugars was reported as early as 1883 (Harris, 1949) and there has been a simultaneous saccharification and fermentation of cellulose into different useful products (Lastick et al., 1984). This treatment disrupts the hydrogen bonding between cellulose chains and once it has been decrystallized it becomes extremely susceptible to hydrolysis. Diluted acid was introduced in the process as a pretreatment agent to remove the hemicellulose content of


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biomass before decrystallization and hydrolysis of the cellulose fraction (LaForge and Hudson, 1918) while Castellonos et al. (1995) reported the comparative evaluation of hydrolytic efficiency toward microcrystalline cellulose of Penicillium & Trichoderma cellulases.

Improvements in acidsugar separation and recovery have opened the door for commercial applications and the current economics of this opportunity are driven by the availability of a cheap feedstock that usually poses a disposal or waste problem (Sheeman and Himmal, 1999). POTENTIAL BIOBASED PRODUCTS AND APPLICATIONS Wastes from biomass can also provide raw materials for a diversity of biobased products. For e.g. plastics from biomass are being produced using polylactic acid from corn. According to Block (1999) executive order and proposed bill will boost biobased products and bioenergy in nations that sees the need for it. Production of Biofuel The demand for ethanol has the most significant market where ethanol is either used as a chemical feedstock or as an octane enhancer or petrol additive Brazil produces ethanol from the fermentation of cane juice whereas in the USA corn is used. In the US, fuel ethanol has been used in gasohol or oxygenated fuels since the 1980s. These gasoline fuels contain up to 10% ethanol by volume (Sun and Cheng, 2002). The production of ethanol from sugars or starch impacts negatively on the economics of the process, thus making ethanol more expensive compared with fossil fuels. However, the huge amounts of residual plant biomass considered as waste can potentially be converted into various different value-added products including biofuels, chemicals, and cheap energy sources for fermentation, improved animal feeds and human nutrients. High energy liquid fuels are also derived from plants (Nemethy et al., 1980). Production of Biogas Biogas is a renewable fuel and electricity produced from it can be used to attract renewable energy subsidies in some parts of the world (Wikipedia, 2008). Depending on where it is produced, biogas can also be called swamp, marsh, landfill or digester gas. A biogas plant is the name often given to an anaerobic digester that treats farm wastes or energy crops. Biogas can be produced utilizing anaerobic digesters. These plants can be fed with energy crops such as maize silage or biodegradable wastes including sewage sludge and food waste. The prospects for biogas cannot be underestimated (Pankhurst, 1983). The composition of biogas varies depending upon the origin of the anaerobic digestion process. Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55-75% CH4 (Adelaide, 2007; Kolumbus, 2007; Wikipedia, 2008).

Biogas can be utilized for electricity production, space heating, water heating and process heating. If compressed, it can replace compressed natural gas for use in vehicles, where it can fuel an internal combustion engine or fuel cells. Methane within biogas can be concentrated to the same standards as natural gas, when it is, it is called biomethane. If concentrated and compressed it can also be used in vehicle transportation (Wikipedia, 2008).


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Production of Biorefinery Products The most profitable way to operate a biomass-to-ethanol plant is as a refinery producing a variety of products from processing all the chemical components (hemicelluloses, cellulose, lignin, and extractives) of cellulosic feedstock. The plant could make use of extractives by converting them to resin acids, or pharmaceuticals (taxols from specific conifers, for example). Cellulose derivatives can be processed into a variety of products including higher value animal feeds. Production of Biodiesel Biodiesel production is a completely renewable resource. Biodiesel product is made from soya and canola, which is a self-sustaining fuel. Best of all it provides a market for excess soya bean oil production. Biodiesel is a substitute for fuels that produce a lot of soot and carbons. These poisonous elements, which are, associated with regular diesel fuel emissions (especially buses). However, biodiesel has been around for decades as a supplement that is added to conventional diesel fuel to improve the lubricity of diesel engines. A Biodiesel fuel consists of methyl esters of soybean oil. Many car manufacturers are seeing the wisdom of creating vehicles that can accommodate a biodiesel product by creating a diesel car that is friendly to the use of vegetable oil blended with diesel fuel. In addition to displacing North America's reliance on imported petroleum, the use of biodiesel product has been shown to reduce air pollution and greenhouse gases. PRODUCTION OF ENZYMES Production of Cellulases and Hemicellulases Cellulases and hemicellulases have numerous applications and biotechnological potential for various industries including chemicals, fuel, food, brewery and wine, animal feed, textile and laundry, pulp and paper and agriculture (Farooq et al., 1994; Bhat, 2000; Sun and Cheng, 2002; Wong and Saddler, 1992a, b; Beauchemin et al., 2001, 2003). Hemicellulases are used for pulping and bleaching in the pulp and paper industry where they are used to modify the structure of xylan and glucomannan in pulp fibres to enhance chemical delignification (Suurnkki et al., 1997; van Wyk, 1999a). Goyal et al (1991) expounded more on the characteristics of fungal cellulases while Kim et al (1998) studied the factorial optimization of a six cellulase mixture. Production of Xylanases In the baking industry xylanases are used for improving desirable texture, loaf volume and shelf-life of bread. A xylanase has shown excellent performance in the wheat separation process (Christopherson et al., 1997). Production of New enzyme systems Valuable substances produced by organisms can be growing on food processing wastes. Diacetyl reductase, for example, has been isolated, purified, and characterized by some researchers. This enzyme is of industrial interest for the production of specialty chemicals from fats and oils. -glucosidase was produced by Aspergillus niger grown on fruit pomace. This enzyme is now under investigation for enzymatic release of natural flavors from food processing residues.


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PRODUCTION OF OTHER HIGH-VALUE BIOPRODUCTS Production of Xanthan Xanthan are produced by fermentation using glucose as the base substrate but theoretically these same products could be manufactured from lignocellulose waste. Production of Xylitol Xylitol used instead of sucrose in food as a sweetner, has odontological applications such as teeth hardening, remineralisation, and as an antimicrobial agent, it is used in chewing gum and toothpaste formulations (Roberto et al., 2003; Paraj et al., 1998). Various bioconversion methods, therefore, have been explored for the production of xylitol from hemicellulose using microorganisms or their enzymes (Nigam and Singh, 1995). PRODUCTION OF INDUSTRIAL CHEMICALS In recent times, many developed countries have returned to carbohydrate based industries for industrial products (Louwrier, 1998). Renewable fuel production includes fuels such as ethanol, methanol, and hydrogen, biodiesel, and Fischer-Tropsch (FT) liquids (fuels derived using the Fischer-Tropsch conversion process). The FT process can produce diesel, naptha, and other fuels that can be used as substitutes for gasoline. Landfills produce a methane rich biogas that is most commonly used for power generation as previously discussed by many authors. Bioconversion of wastes could make a significant contribution to the production of organic chemicals (Coombs, 1987). Other examples of production of industrial chemicals produced in biofilm reactors include acetic acid or vinegar, lactic acid, succinic acid, and fumaric acid. Production of Ethanol There have been increased industrial uses of agricultural commodities to produce different products (Lee, 1994). The production of ethanol from biowaste can improve energy security and decrease pollution (Forward, 1994). Akpan et al. (1988) produced ethanol from gari effluents using Aspergillus niger in a one-step fermentation process. Rajagopal (1977) prepared a beer using cassava. The same can be done using garri effluent to produce different types of alcoholic beverages. Ethanol has been produced continuously in an attached biofilm expanded bed bioreactor of Zymomonas mobilis and Saccharomyces cerevisiae in biofilm reactors (Bland et al., 1982; Kunduru and Pometto, 1996) while Krug and Daugulis (1983) used Zymomonas mobilis immobilized on an ion exchange resin for ethanol production. Adsorbed cells of Saccharomyces cerevisiae have also been used in a packed bed continuous bioreactor to produce ethanol from molasses (Tyagi and Ghose, 1982). Lynd et al (1991) investigated ethanol yield and tolerance in continuous culture during thermophilic ethanol production.

Ethanol is an excellent transportation fuel and blends of it have benefits, such as reduced gasoline use, thus lowering the need for fossil fuels. It also improves the performance of an ethanolgasoline blend and ethanol provides oxygen for the fuel resulting in a more complete combustion with a low atmospheric photochemical reactivity. Even though CO2 is released during the fermentation of sugars to form ethanol and the burning of ethanol as a fuel, the CO2 is reutilized to grow new biomass replacing that harvested for ethanol production (Maddox, 1989). Production of Butanol/2,3-Butanediol Butanol is an important industrial chemical that can be produced from a number of carbohydrates using a number of microbial cultures. Butanol can be used as a fuel and has higher/greater energy content than ethanol (Maddox, 1989). Continuous production


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of 2, 3-butanediol from whey permeate using cells of Klebsiella pneumoniae immobilized on to bonechar was reported by Maddox et al (1988). Production of Acetic Acid/Vinegar Commercial production of acetic acid or vinegar using biofilm reactors as a bioconversion technology has been exercised for many years (Maddox, 1989). Production of these chemicals has been reported by Crueger and Crueger (1989). The percentage of starch (72%) in cocoyam was exploited in the production of ethanol and vinegar by Braide et al. (2005). Statistically, there exist a significant difference in the aroma and colour, but not in taste between cocoyam vinegar compared with commercial cider and white vinegar at 95% confidence limit. The acetic acid is produced by one of the bacteria grouped in the two genera, Gluconobacter and Acetobacter. The species that are used commercially include Acetobacter aceti, A. pasteurianus, and Gluconobacter oxydans. Production of Fumaric Acid Biofilm reactors as a bioconversion technology have also been used successfully for the production of fumaric acid from glucose (Cao et al., 1996) and mineral ore treatment (Crueger and Crueger, 1989). Production of Citric Acid Citric acid (CA) is a carboxylic organic acid that is soluble in water with a pleasant taste. It is the most important acid used in the food industries. Until about 1920, all commercial CA was produced from lemon and lime juices. Rohr et al. (1983) reported that CA can be produced by fermentation process using species of microorganisms namely Aspergillus niger, a fungus which was used commercially for the first time in 1923 (Xu et al., 1989) and in solid-substrate fermentation (Lu, 1995). Sugar source has effect on the citric acid production by Aspergillus niger (Hossain et al., 1984; Murad et al., 2003). Production of Lactic Acid Production of lactic acid in biofilm reactors is another example of industrial chemical production in such reactors as a bioconversion technology. Demirci et al. (1993a, b) evaluated a number of supports for biofilm formation using lactic acid producing cultures. Lactic acid was produced in repeated batch cultures in a biofilm reactor. Production of Succinic Acid Succinic acid is a chemical that has been produced in biofilm reactors during bioconversion processes. The industrial potential for succinic acid fermentation was recognized as early as the late 1970s (Zeikus et al., 1999). Succinic acid (HOOCCH2CH2COOH) is a dicarboxylic acid, which can be used as a feedstock chemical for the production of high value products such as 1,4-butanediol, tetrahydrofuran, adipic acid, -butyrolactone, and n-methylpyrrolidone for applications in agriculture, food, medicine, plastics, cosmetics, and textiles. Production of forage Manures have been used as fertilizer for centuries, but crop fertilization with manure has received renewed attention in recent years as concern for water pollution potential from excess manure has increased. However, the content will vary depending on the type of animal, the feed that was consumed, the way the manure was handled, and other factors. Large, concentrated animal operations such as dairies and layer houses generally import more nutrients onto the farm in feed than goes out in milk, eggs, and animals (Johnson et al., 1991).


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Forage producers can make good use of many materials considered wastes. Layer and broiler manure, dairy manure, septage and biosolids, composted urban plant debris, phosphogypsum, and waste lime from municipal water treatment plants are examples of materials that can be used for fertilizing and liming pastures and fields. Often these materials can be obtained at little or no cost to the farmer or rancher. In some circumstances the land owner may be paid for taking the waste, thus collecting a disposal fee while the soil and crops benefit from the materials added. Forage crops such as corn silage and hay are excellent candidates for such application since they remove nutrients in significant quantities (Kidder, 2002). APPLICATION POTENTIALS OF BIOPRODUCTS The question now will be do food wastes pollute the soil? Not if the materials are chosen carefully and applied properly. A waste in one situation can be a resource in another. Animal manures have been returned to the land as fertilizer and soil conditioner for centuries. Yard wastes have much the same composition as crop residues, which are considered an asset in good soil management. The Center for Biomass Utilization focuses on developing the following technologies: Cofiring biomass with coal using agricultural wastes and food-processing wastes to produce transportation fuels and chemical feedstocks.

A wide variety of biomass resources are available on our planet for conversion into bioproducts. These may include whole plants, plant parts (e.g. seeds, stalks), plant constituents (e.g. starch, lipids, protein and fibre), processing byproducts (distillers grains, corn solubles), materials of marine origin and animal byproducts, municipal and industrial wastes (Smith et al., 1987). These resources can be used to create new biomaterials and this will require an intimate understanding of the composition of the raw material whether it is whole plant or constituents, so that the desired functional elements can be obtained for bioproduct production (Howard et al., 2003).

Application of biotechnology to the processing of food (including beverages) produced from agriculture has proved highly valuable (Cooper, 2003). Indeed, the combination of bio-based feedstock, bio-processes and new products offers the potential to revolutionize chemical industry structures. In less than 10 years, integrated bio-refineries will play a role comparable to today's oil and gas crackers. They will make use of row crops, energy crops, agricultural waste and food waste as inputs to extract oil and starch for food, protein for feed, lignin for combustion, cellulose for conversion into fermentable sugars, as well as other by-products.

Sugar will be the key feedstock of the future, as it can be used to ferment ethanol for transportation fuel, but also for a whole set of new, basic building blocks. Molecules such as lactic acids, succinic acid, propylene glycol or 3-hydroxy propionic acid produced at 20 cents per pound can catalyze the innovation of new chemical product families, similar to the innovation boost based on the cracker chemicals in the middle of this 21st century. Indeed, the combination of bio-based feedstock, bio-processes and new products offers the potential to revolutionize chemical industry structures.

Biogas is used extensively throughout rural China and where wastewater treatment and industry coincide (Wikipedia, 2008). The Biogas Support Program in Nepal has installed over 100,000 biogas plants in rural areas. Vietnams Biogas Programme for Animal Husbandry Sector has led to the installation of over 20,000 plants


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throughout that country. Biogas is also in use in rural Costa Rica. In Colombia experiments with diesel engines-generator sets partially fuelled by biogas demonstrated that biogas could be used for power generation, reducing elecricity costs by 40% compared with purchase from the regional utility (Wikipedia, 2008). Owing to simplicity in implementation and use of cheap raw materials in villages, it is one of the most environmentally sound energy sources for rural needs.

Fossil oil and natural gas are being replaced by carbohydrates from renewable resources as low-cost, renewable feedstock. in particular, the development of technology to convert cellulosic biomass from agricultural waste, food waste or energy crops into fermentable sugars offers the perspective of producing ethanol and other bulk organic chemicals at low cost. The cost of biomass-based ethanol produced on a commercial scale, for example, is expected to undercut the cost of gasoline with oil at $30 per barrel. A first semi-commercial ethanol plant using straw is being operated by Iogen and Shell in Canada. More companies have started their own endeavors in this field, including Dupont, John Deere, Genencor, Novozymes, and Abengoa.

Entirely new bio-based products are competing against conventional products on the basis of a superior cost/performance ratio, or are even fulfilling unmet market needs. Enzymes, for example, are fast-growing bio-products that make washing powder more effective, allow softer processing of textiles and pulp and paper, and reduce nitrogen emissions from animal farming. Other examples are biopolymers; cargill dow's pla (polylactide) offers a green alternative to pla at similar cost and performance - two large-scale plants for further new bio-polymers are under construction - Dupont's Sorona and Metabolix's phas (polyhydroxyalkanoate). BENEFITS OF SUSTAINABLE UTILIZATION OF FOOD WASTE Compared to burning fossil fuel, there may be benefits associated with greenhouse gas reduction with the creation of markets for agricultural waste where its disposal has a negative effect on the environment. For example, the use of biomass as feedstock reduces net carbon emissions to the atmosphere and provides reductions in methane emissions from natural decay processes. The ecologically responsible removal of slash from logged areas benefits the environment. The use of other agricultural residues also reduces emissions of volatile organic compounds, odors, dust, and nuisances associated with agricultural operations such as dairies and animal feeding operations. Improved management of animal manure and solid wastes also reduces ground water contamination (MWPS, 1993).

There are economic benefits from the biomass based industrial activities such as electricity generation, erosion control, and for the production of fuels, animal feed, and green or renewable chemicals (such as solvents and lubricants, polymers and plastics) and increased food productivity. Total economic benefits derived from these activities depend on the mixture of biomass based products generated from it, as well as the state of maturity of these industries. CONSIDERATIONS FOR SUSTAINABLE UTILIZATION OF FOOD WASTE

1. The effect of utilization of food waste on the water budget should be considered, particularly where a shallow ground water table is present or in areas prone to runoff.


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2. Minimize the impact of odors of land-applied food wastes by making application at times when temperatures are cool and when wind direction is away from neighbors.

3. Food and agricultural wastes contain pathogens. Wastes should be utilized in a manner that minimizes the disease potential to humans or animals.

4. Flushing of animal wastes offers several advantages for the livestock producer including labor efficiency and a more pleasant if not actually healthier environment in animal housing areas (Nordstedt and Baldwin, 2002).

CHALLENGES OF SUSTAINABLE WASTE UTILIZATION Pollution of surface waters Pollution of surface waters may result from runoff of applied food waste materials. To prevent this, one should not apply waste to frozen or saturated soils. Incorporating surface-applied food waste into soil will limit overland movement of nutrients and organic matter detrimental to water quality. Check "hydraulic loading" of waste application to ensure that the volume of liquid applied does not exceed the soil's percolation and water holding potential (MWPS, 1993). High Production Costs The cost of processing cellulosic materials to produce ethanol is high. The development of new technologies has significantly decreased the cost of producing ethanol, particularly corn-derived ethanol. However, for some, technologies for cellulosic ethanol production are currently in the experimental state, while others believe that these technologies are already sufficiently mature but have not been widely applied due to lack of capital, which is difficult to attract for the implementation of new technologies (MWPS, 1993). CONCLUSIONS AND RECOMMENDATION As the current trend in the world today is to utilize and convert waste into useful products and to recycle waste product as means of achieving sustainable development. Among the conversion processes and product developments discussed thus far, methane and ethanol production from various food wastes and energy food crops is economically feasible within the restraints of scale and location. Although biological processes for the production of gaseous and liquid fuels have been well demonstrated with cultured microalgal biomass as reported by most authors, these processes must still be integrated into a system capable of meeting basic requirements for overall efficiency of converting solar energy into biofuels. Furthermore, a model system must at least in principle, be capable of easy scale-up and not be limited by either engineering or economic factors. Under the current petroleum economy in Nigeria, prospects for the use of H2 or oils produced by biological processes seem remote in this part of the world.

Bioproduct development would influence the activities of the food, pharmaceutical, cosmetic and petroleum sectors more in the future as the pressure on waste management and biodevelopment increases. As with any development, the sustainable re-use of food waste resources would not be without difficulties, but it would open up the opportunity for biotechnological developments. The economic environment would need to foster the type of conditions in which the emergent food industry can thrive.


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The same strategic imperatives, socio-economic growth and sustainable developmental issues, which drove Western countries research into waste utilization since the 1970s are of even greater and progressing relevance to developing countries like Nigeria. Although, developing countries are still grappling with socioeconomic issues including meeting the massive energy shortage demands, food security and developing biotechnological solutions in the agriculture, agro-processing and other related manufacturing sectors. Therefore to manage food wastes, the general pathways of industrial-food waste generation should be reduced, recycled or reused and what is left must be treated and disposed of in an environmentally acceptable way. If a process is not environmentally friendly, it should be redesigned such that it becomes so and where a process cannot be redesigned, then it is necessary to reconsider whether it should be undertaken at all.

REFERENCES

1. Adelaide (2007). Safety Page, Beginners Guide to Biogas, www.adelaide.edu.au/biogas, retrieved 22.10.07

2. Akpan I, Ikenebonem M.J, Uraih N, Obuekwe CO. (1988). Production of ethanol from cassava effluent. Acta of Biotechnologica 8:39-45

3. Aririatu LE, Gwadia OT, Nwaokeocha CC. (1999). The Bioremediation Potential of some local Natural Coagulants. Nig. J. Microbiology 13: 65-69.

4. Arotupin DJ, Akinyosoye F.A. (2001). Evaluation of Microbial Isolates from Sawdust for Cellulose Hydrolyis. Nigerian Journ. of Microbiology 15 (1): 97-102

5. Ashiru AW. (2005a). Comparative Evaluation of Ethanol Production by Lignocellulose-Fermenting Microorganisms. In: the Book of Abstract of the 29th Annual Conference & General Meeting (Abeokuta 2005) on Microbes As Agents of Sustainable Development, organized by Nigerian Society for Microbiology (NSM), UNAAB, Abeokuta, from 6-10th November, 2005. p22.

6. Ashiru A.W. (2005b). Production of Ethanol from Molasses and Corncobs Using Yeasts and A Mould. In: the Book of Abstract of the 29th Annual Conference & General Meeting (Abeokuta 2005) on Microbes As Agents of Sustainable Development, organized by Nigerian Society for Microbiology (NSM), University of Agriculture, Abeokuta, from 6-10th November, 2005. p22.

7. Asano Y, Komeda T and Yamada H (1993). Microbial Production of Theobromine From Caffeine. Bioscience Biotechnology Biochemistry, 57:1286-1289.

8. Baig MMV, Mane VP, More DR, Shinde LP, Baig MIA (2003). Utilization of Agricultural Waste of Banana: Production of Cellulases by Soil fungi, J. Environ. Biol. 24:173 -176.

9. Bankole MO, Aina MA. (2004). Sourcing Local Plant Tubers as Alternative Laboratory Media for Fungi Growth. In: the Book of Abstract no. 68 of the 1st International Conference on Science and National Development, organized by College of Natural Sciences, UNAAB, from 25-28th October, 2004. p63

10. Bankole MO, Omemu AM, Adegbesan AM. (2006). Sourcing maize cobs as alternative Laboratory media for microbial Growth (Personal Communication).

11. Becker RB, Arnold PTD, Davis GK, Fouts EL. (1946). "Citrus molasses." Fla. Agr. Exp. Sta. Press Bul. 423p.

12. Beauchemin KA, Colombatto D, Morgavi DP, Yang WZ. (2003). Use of exogenous fibrolytic enzymes to improve animal feed utilisation by ruminants. Journal Animal Sciences 81(E. Suppl.2): E37-E47.

13. Beauchemin KA, Morgavi DP, Mcallister TA, Yang WZ, Rode LM (2001). The use of enzymes in ruminant diets. In Wiseman J, Garnsworthy PC (eds) Recent Advances in Animal Nutrition. Nottingham University Press, pp 296-322.

14. Beauchemin KA, LM Rode, VJH Sewalt. (1995). Fibrolytic enzymes increase fibre digestibility and growth rate of steers fed dry forages. Can. J. Anim. Sci. 75:641-644.


281

15. Bhat MK (2000). Research review paper: Cellulases and related enzymes in biotechnology. Biotechnol. Adv. 18:355-383.

16. Bland RR, Chen HC, Jewell WJ, Bellamy WD, Zall RR. (1982). Continuous high rate production of ethanol by Zymomonas mobilis in an attached film expanded bed fermentor. Biotechnol Let, 4:323-328.

17. Block D (1999) Executive order and proposed bill will boost biobased products and bioenergy. Biocycle Magazine 40, 5557

18. Braham JE, Bressani R (1987). Coffee Pulp. In: Other Species. In: Brahan, J.E.; Bressani, R. (Ed.) Coffee Pulp: Composition, Technology, and Utilization. Guatemala City: Institute of Nutrition of Central America and Panama, p51-54.

19. Braide W, Agbaroji JE, Anyanwu BN. (2005a). Production of Vinegar from Cocoyam (Colocesia esculenta) extracts. In: the Book of Abstract of the 29th Annual Conference & General Meeting (Abeokuta 2005) on Microbes As Agents of Sustainable Development, organized by Nigerian Society for Microbiology (NSM), UNAAB, Abeokuta, from 6-10th November, 2005. p14

20. Braide W, Agbaroji JE., Anyanwu BN. (2005b). Production of Ethanol (Alochol) from Mash Extracts of Cocoyam (Colocesia esculenta). In: the Book of Abstract of the 29th Annual Conference & General Meeting (Abeokuta 2005) on Microbes As Agents of Sustainable Development, organized by Nigerian Society for Microbiology (NSM), UNAAB, from 6-10th Nov, 2005. p14

21. Bressani R, Braham JE (1987a). Anti-physiological Factors In: Coffee Pulp. In: Brahan, JE; Bressani, R. (Ed.) Coffee Pulp: Composition, Technology, and Utilization. Guatemala City: Institute Of Nutrition Of Central America And Panama, pp83-88.

22. Bressani R, Braham JE (1987b). Potential Uses of Coffee Berry Byproducts. In: Brahan, JE; Bressani, R. (Ed.) Coffee Pulp: Composition, Technology, and Utilization. Guatemala City: Institute of Nutrition of Central America and Panama, Pp 17-25.

23. Cabezas MT, Flores A, Egana JI. (1987). Use of Coffee Pulp In: Ruminant Feeding. In: Brahan, JE, Bressani R (Ed.) Coffee Pulp: Composition, Technology, and Utilization. Guatemala City: Institute of Nutrition of Central America and Panama, Pp.25-38.

24. Cao N, Du J, Gong CS, Tsao GT (1996). Simultaneous production and recovery of fumaric acid from immobilized Rhizopus oryzae with a rotary biofilm contactor and an adsorption column. Appl Env Microbiol, 62:2926-2931.

25. Castellonos OF, Sinitsyn AP, Vlasenko EY (1995). Comparative evaluation of hydrolytic efficiency toward microcrystalline cellulose of Penicillium & Trichoderma cellulases. Biores Tec 52:119-24.

26. Chahal DS (1992). Bioconversions of poysaccharides of lignocellulose and simultaneous degradation of lignin. In Kennedy et al. (eds) Lignocellulosics: Science, Technology, Development and Use. Ellis Horwood Limited, England, pp. 83-93.

27. Chukwura EI, Onuoha SC. 2005. Bacterial Degradation of Chicken Feathers. In: the Book of Abstract of the 29th Annual Conference & General Meeting on Microbes As Agents of Sustainable Development, organized by Nig. Soc. for Mic. (NSM), UNAAB, from 6-10th Nov, 2005. p54.

28. Chukwura EI, Okotie B, Ugwu IF, Alukwe UJ, Anisi CCG, Olowe OV. 2005. Co-composting of Garden Refuse (Grass) and Human Faeces, Cow Dung, Chicken Dropping with Human Male and Female Urine: A Comparative Analysis. In: the Book of Abstract of the 29th Annual Conference & General Meeting (Abeokuta 2005) on Microbes As Agents of Sustainable Development, organized by Nigerian Society for Microbiology (NSM), UNAAB, from 6-10th Nov, 2005. p58.

29. Dabai YU, Muhammed S. (2004). Cassava Starch as an Alternative to Agar-agar in Microbiological Media. In: the Book of Abstract no. 60 of the 1st International Conference on Science and National Development, organized by Colle. of Natural Sci., UNAAB, from 25-28th Oct, 2004. p57

30. Eka OA. 1986. Studies of Microbiodeterioration of Substances of Industrial Importance. Nigerian Journal of Microbiology 6 (1-2): 136-142

31. Kareem SO, Akpan I. (2004). Pectinase Production by Rhizopus sp. Cultured on Cheap Agricultural Materials. In: the Book of Abstract no. 56 of the 1st International Conference on


282

Science and National Development, organized by Colle. of Nat. Sci., UNAAB, from 25-28th Oct, 2004. p53

32. NRCS (2002). Agricultural Waste Management. Illinois Agronomy Handbook, the USDA- NRCS Agricultural Waste Management Field Handbook, 1-14

33. Nordstedt RA, LB Baldwin (2002).Some Devices for Flushing Animal Wastes. CIR871, Agricultural Engineering Extension Report 85-5, one of a series of the Agricultural and Biological Engineering Department, Florida Coop. Ext. Service, Inst. of Food and Agric. Sci., University of Florida.

34. Christopherson C, Anderson E, Jokobsen TS, Wagner P (1997). Xylanases in wheat separation. Starch 49:5-12.

35. Coombs J (1987). EEC resources and strategies. Phil. Trans. R. Soc. Lond. Ser. A. 321: 405-422.

36. Cooper (2003). Application of biotechnology to the processing of food (including beverages) produced from agriculture. http://www.pubmedcentral.nih.gov/articlerender.fcgi

37. Crueger W, Crueger C (1989). Organic acids. In "Biotechnology" A textbook of industrial microbiology. Sinauer Associates, Inc., Sunderland. MA. p446

38. Dale BE (1987). Lignocellulose conversion and the future of fermentation technology. Trends Biotechnol. 5(10): 287-291.

39. Demirci A, Pometto AL III, Johnson KE (1993a). Evaluation of biofilm reactor solid support for mixed-culture lactic acid production. Journal of Applied Microbiology and Biotechnololgy 38:728-733.

40. Demirci A, Pometto AL III, Johnson KE (1993b). Lactic acid production in a mixed-culture biofilm reactor. Journal of Applied Microbiology and Biotechnololgy 59:203-207.

41. Farooq L, Rajoka MI, Malik KA (1994). Saccharification of Leptochloa fusca (Kallar grass straw) using thermostable cellulases. Biores. Technol. 50: 107-112.

42. Forward P (1994). Beyond ethanol: Industrial uses of agricultural materials. Background opportunities paper. Food Bureau, Market and Industry Services Branch, Agric & Food Dept, Ottawa, Ca

43. Goyal, A. et al. (1991). Characteristics of fungal cellulases. Biores. Technol. 36, 3750 44. Grethlein HE, Converse AO (1991). Common Aspects of acid prehydrolysis and steam

explosion for pretreating wood. Biores. Technol. 36:77-82. 45. Gupta S (1994). Continuous production of citric acid from sugar cane molasses using a

combination of submerged immobilized and surface stabilized cultures of Aspergillus niger, KCU520. Biotechnol. Lett. 16: 599-604.

46. Harris EE (1949) Wood Saccharification. In Advances in Carbohydrate Chem., Academic press, New York, 4:15388

47. Haug RT (1993). The Practical Handbook of Compost Engineering. Lewis Pub., Boca Raton, Fl, USA

48. Hendrickson R, Kesterson DW. (1965). "By-products of Florida citrus." Florida Agricultural Experimental Station Bulletin p698.

49. Horsfall M Jnr, Abia, AA, Spiff AI. (2003). Removal of Cu (II) and Zn (II) ions from wastewater by cassava (Manihot esculenta Cranz) waste biomass. Afr. J. Biotechnology, 2(10):360-364

50. Hossain M, Brooks JD, Moddax IS. (1984). The effect of the sugar source on citric acid production by Aspergillus niger. Journal of Applied Microbiology and Biotechnololgy 19: 393-397.

51. Howard RL, Abotsi E, Jansen van Rensburg EL, Howard S. (2003). Lignocellulose biotechnology: issues of bioconversion and enzyme production. African Journal of Biotechnology 2(12):602-619.

52. James JE (1991). Caffeine and Health. San Diego: Academic Press, 428p. 53. Jarqun R (1987). Coffee Pulp: Composition, Technology and Utilization. In: Swine Feeding.

(Brahan JE, Bressani R. ed.). Guatemala City: Inst of Nutr of Central America & Panama, P.39-49.

54. Johnson JC, Newton GL, Butler JL. (1991). Recycling liquid dairy waste to sustain annual triple crop production of forages. Proc. Florida Dairy Production Conf., Dairy Science Dept., Univ. Fl. Coop. Ext., Gainesville, FL. 32611.


283

55. Khare SK (1994). Use of agarose-entraped Aspergillus niger cells for the production of citric acid from soy whey. Appl. Microbiol. Biotechnol. 41: 571-573.

56. Kidder G (2002). Using Waste Products in Forage Production. The Florida Forage Handbook, an electronic publication of the Agronomy Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611-0290.

57. Kim E et al (1998). Factorial optimization of a six cellulase mixture. Biotechnol. Bioeng. 58, 494501

58. Kivaisi AK, Rubindamayugi MST (1996). The potential of Agro-industrial residues for production of biogas and electricity. Renew. Energy (1-4): 917-921.

59. Kolumbus (2007). Basic Information on Biogas, www.kolumbus.fi, retrieved 2.11.07 60. Krug TA, Daugulis AJ (1983). Ethanol production using Zymomonas mobilis immobilized on

an ion exchange resin. Biotechnol Lett, 5:159-164. 61. Kunduru MR, Pometto AL III (1996). Continuous ethanol production by Zymomonas mobilis

and Saccharomyces cerevisiae in biofilm reactors. J Ind Microbiol Biotechnol, 16:249-256 62. LaForge FB, Hudson CS. (1918). The preparation of several useful substances from corn

cobs. Journal of Industrial Engineering and Chemistry 10: 925927 63. Lee H (1994) Increased industrial uses of agricultural commodities: policy, trade and ethanol.

Cont. Econ. Pol. 12, 22322250 64. Louwrier A (1998) Industrial products return to carbohydrate based industries.

Biotechnology and Applied Biochemistry 27: 18 65. Lu MY (1995) Citric acid production by Aspergillus niger in solid-substrate fermentation.

Bioresour. Technol. 54: 235-573. 66. Lynd LR et al (1991) Thermophilic ethanol production investigation of ethanol yield and

tolerance in continuous culture. Appl. Biotech. 28: 549553 67. Maddox IS Qureshi N, McQueen J. (1988). Continuous production of 2,3-butanediol from

whey permeate using cells of Klebsiella pneumoniae immobilized on to bonechar. New Zealand J Dairy Science and Technology 23:127-132.

68. Maddox IS (1989). The acetone, butanol, ethanol fermentation: recent progress in technology. Biotechnol Genetic Engineering Reviews 7:190-220.

69. Mazzafera Paulo (2002). Degradation of Caffeine by Microorganisms and Potential Use of Decaffeinated Coffee Husk & Pulp in Animal Feeding. Sci. agric. (Piracicaba, Braz.) 59(4) Oct./Dec. 2002

70. Mazzafera P, Olsson O, Sandberg G. (2002). Degradation Of Caffeine and Related Methylxanthines By Serratia Marcescens Isolated From Soil Under Coffee Cultivation. Micro Ecology 31:199-207

71. McLanglin LA (1992). Developing Effective Waste Water Treatment Strategy. Chemical Engineering Progress 88 (9) 34-42.

72. MidWest Plan Service (MWPS, 1993). Livestock Waste Facilities Handbook. MWPS-18. ($8) MidWest Plan Service, 122 Davidson Hall, Iowa State University, Ames, IA 50011-3080. (800) 562-3618

73. Moddax IS, Hosain M, Brooks JD. (1986). The effect of methanol on citric acid production from galactose by Aspergillus niger. Journal of Applied Microbiology and Biotechnology 23:203-205.

74. Muchovej RM, Obreza TA. (2004). Utilization of Organic Wastes in Florida Agriculture. Southwest Florida Research and Education Center, Immokalee, FL; Florida Cooperative Ext. Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.

75. Muchovej RM, Obreza TA. (2001). Biosolids: Are These Residuals All the Same? Fact Sheet, SS-AGR-167.

76. Murad A. El-Holi, Khalaf S. Al-Delaimy (2003). Citric acid production from whey with sugars and additives by Aspergillus niger. African Journal of Biotechnology, 2 (10): 356-359

77. Myer RO, Brendemuhl JH, Johnson DD. (1999). Evaluation of dehydrated restaurant food waste products as feedstuffs for finishing pigs. J. Anim. Sci. 77:685.

78. Neal WM, Becker RB, Arnold PTD (1935). "The feeding value and nutritive properties of citrus by-products. 1. The digestible nutrients of dried grapefruit refuse for growing heifers." Fla. Agr. Exp. Sta. Bul. 275.


284

79. Nemethy EK, Otvos JW, Calvin M (1980). High energy liquid fuels from plants. In: Klass DL. and Emert, EH. (eds.), Fuels from biomass. 777p

80. Nguyen QA et al (1999). Bioconversion of mixed solids waste to ethanol. App Bioche. Biotec.77:45571

81. Nicolella C, van Loosdrecht MCM, Heijnen SJ. (2000). Particle-based biofilm reactor technology. Trends in Biotechnol (TIBTECH), 18:312-320.

82. Nigam P, Singh D (1995). Processes for fermentative production of xylitol a sugar substitute: A review: Process Biochem. 30(2):117- 124.

83. NST (2005). Friendly fuel trains. New Straits Times, (Oct. 30, 2005) p. F17. 84. Obire O, Akind SB. (2005a.) Comparative Effectiveness of Animal Manures on Soil Fertility:

A Cost Effective Fertilization Approach Towards Agronomic Sustainability. In: the Book of Abstract of the 29th Annual Conference & General Meeting on Microbes As Agents of Sustainable Development, organized by Nig. Soc. for Microbio.(NSM), UNAAB, from 6-10th Nov, 2005. p53.

85. Obire O, Akind SB. (2005b). Comparative Study of the Efficiency of Cow Dung and Poultry Manure as Alternative Nutrient Sources in Bioremediation of Oil-polluted Soil. In: the Book of Abstract of the 29th Annual Conference & General Meeting on Microbes As Agents of Sustainable Development, organized by Nig. Soc. for Microbio.(NSM), UNAAB, from 6-10th Nov, 2005. p55.

86. Obreza TA, GA O'Connor (2003).The Basics of Biosolids Application to Land in Florida. One of a series of the Soil & Water Sci Dept, Florida Coop. Ext Ser, Inst of Food & Agric Sci, Univ of Flo.

87. Ojokoh AO. (2005). Effect of Fermentation on Mango Peels. In: the Book of Abstract of the 29th Annual Conference & General Meeting (Abeokuta 2005) on Microbes As Agents of Sustainable Development, organized by Nig. Soc. for Microbio. (NSM), UNAAB, from 6-10th Nov, 2005. p19

88. Okeke BC, Obi SKC. (1994). Lignocellulose and sugar compositions of some agro waste materials. Bioresource Technol. 50: 222-227.

89. Okeke BC, Obi SKC. (1995). Saccharification of agro wastes materials by fungal cellulases and hemicellulases. Biores. Technol. 51: 23-27.

90. Okonko IO, Olabode OP, Okeleji OS (2006). The role of biotechnology in the socio-economic advancement and national development: An Overview. African J. Biotechnology 5(19):2354-2366

91. Okafor N. (1987). The Use of Plant Wastes. In: Industrial Microbiology. University of Ife Press Limited. Ile-Ife, Nigeria. pp25-36.

92. Omoyinmi GAK, Adebisi AA, Fagade SO. (2004). Farm Organic Wastes in the Production of Animal Protein. In: the Book of Abstract no. 46 of the 1st International Conference on Science and National Development, organized by Col. of Nat. Sci, UNAAB, from 25-28th October, 2004. p43

93. Pankhurst ES (1983). The prospects for biogas-an European point of view. Biomass 3:1-42 94. Paraj JC, Domnquez HD, Domnquez JM (1998). Biotechnological production of xylitol.

Part 1: interest of xylitol and fundamentals of its biosynthesis. Biores. Technol. 65:191-201. 95. Puri VP (1984) Effect of crystallinity and degree of polymerization of cellulose on enzymatic

saccharification. Biotechnol. Bioeng. 26, 12191222 96. Rajagopal MV. (1977). Production of Beer from Cassava. J. Food Science 22:27-39 97. Raji AI, Ameh JB, Ndukwe M. (1998). Production of Cellulose Enzyme by Aspergillus niger

CS 14, from Delignified Wheat Straw and Rice Husk Substrates. Nigerian Journal of Technical Education 15 (1): 57-63

98. Roberto IC, Mussatto SI, Rodrigues RCLB (2003). Dilute-acid hydrolysis for optimization of xylose recovery from rice straw in a semi-pilot reactor. Indust. Crops Prod. 17:171-176.

99. Rohr M, Kubicek CP, Kominek I (1983). Citric acid. In: Biotechnology, HJ Rehm and G Reed, eds., Vol. 3, VCH Publishers, Weinheim, Germany.

100. Roka FM, Muchovej RM, Obreza TA. (2004). Assessing Economic Value of Biosolids. SS-AGR-168, one of a series of the Agronomy Department, Florida Cooperative Ext. Serv., Inst. of Food and Agricultural Sci., University of Florida.


285

101. Roukas T. (1998). Citric acid production from carob pod extract by cell recycle of Aspergillus niger ATCC 9142, Food Biotechnol. 12: 91-104.

102. Safarik I. (1986). Rapid Isolation of Bacterial Proteinases by Column Chromatography on Sawdust. Journal of Basic Microbiology 25 (10): 695-697

103. Santral S, Nandi B. (1980). Decomposition of Structural Components of Sawdust of three Economic Timbers by Three White Rot fungi. Mater. Org. 15 (4): 315-320

104. Scott GM, Aktar M, Lentz MJ, et al. (1998). New technology for papermaking: commercializing biopulping. Tappi J. 81:220-225.

105. Sheeman J, Himmel M. (1999). Enzymes, energy, and the environment: A strategic perspective on the U.S. department of energys research and development activities for bioethanol. Biotechnol. Prog. 15: 817827

106. Shittu OB, Okonko IO, Akpan I. (2007). A Comparative study on the Bioremediation Potentials of Grounded seeds of Moringa oleifera and Latex exudates of Calotropis Procera (Sodom Apple). Nigerian Journal of Microbiology 30: 1419-1024

107. Smith JE, Anderson JG, Senior EK, et al (1987). Bioprocessing of lignocelluloses. Phil. Trans. R. Soc. Lond. Ser. A. 321:507-521.

108. Sun Y, Cheng J (2002). Hydrolysis of lignocellulosic material from ethanol production: A review. Biores. Technol. 83: 1-11.

109. Suurnkki A, Tenkanen M, Buchert J, Viikari L (1997). Hemicellulases in the Bleaching of Chemical Pulp. In Scheper (eds) Advances in Biochemical Engineering/Biotechnology. Springer-Verlag Berlin, Heidelberg, pp 262- 284.

110. Take H, Mtui G, Kobayashi F, Nakamura Y (2005). Additive effect of soybean curd residue, Okara, for enhancement of methane production from pretreated woody waste. J. Food Techno.3(4):535-537.

111. Tran CT, Sly LI, Mitchel DA. (1998). Selection of a strain of Aspergillus for the production of citric acid from pineapple waste in solid-state fermentation. World J. Microb. Biotechnol. 14: 399-404.

112. Tyagi RD, Ghose TK. (1982): Studies on immobilized Saccharomyces cerevisiae. I. Analysis of continuous rapid ethanol fermentation in immobilized cell reactor. Biotechnol Bioeng 24:781-795.

113. Uzochukwu SVA, Oyede R, Atanda O. (2001). Utilization of Gari Industry Effluent in the Preparation of a Gin. Nigerian Journal of Microbiology 15 (1): 87-92

114. Valvonou BM. (1989). Cassava processing technologies in Africa. In: Praise of Cassava. Proceedings of the Interregional Expert Group Meeting on the Exchange of Technology and Food Products held at IITA, Ibadan, Nigeria. 13-19th April, 1988. Dan NH (ed.). Intech, Ibadan Pp 9-25

115. Van Wyk JPH. (2001). Biowaste as a resource for bioproduct development. TRENDS in Biotechnology 19 (5): 172-177

116. Van Wyk JPH. (1999a). Hydrolysis of pretreated paper materials by different concentrations of cellulase from Penicillium funiculosum. Biores. Technol. 69, 269273

117. Van Wyk JPH. (1999b). Saccharification of paper products by cellulase from Penicillium funiculosum and Trichoderma reesei. Biomass & Bioenergy. 16, 239242

118. Van Wyk JPH. (1999c). Cellulase catalyzed hydrolysis of cellulose materials: pH and temperature profiles. Resource Environ. Biotechnol. 2, 249254

119. Wikipedia (2008). Biogas From Wikipedia, the free encyclopedia. Retrieved 28.03.08 120. Wing, JM (1975). "Effects of physical form and amount of citrus pulp on utilization of

complete feeds for dairy cattle." J. Dairy Sci. 58:63. 121. Wing JM, Becker B, Van Horn HH, Randall PF, CJ Wilcox, SP Marshall, H Roman-Ponce,

GE Schaibly, FJ Pinzon, B Harris Jr., MB Olyaiwole, SD Sklare, and KC Bachman (2003). Citrus Feedstuffs for Dairy Cattle. Department of Dairy Science. Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611.

122. Wong KKY, Saddler JN (1992a). Applications of hemicellulases in the food, feed and pulp and paper industries. In Coughlan PP, Hazlewood GP (eds) Hemicellulose and Hemicellulases. Portland Press, London, pp. 127-143.


286

123. Wong KKY, Saddler JN (1992b). Trichoderma xylanases: their properties and applications. In Visser et al. (eds) Xylans and their Xylanases. Elsevier, Amsterdam, pp. 171-186.

124. Wyman CE, Goodman BJ (1993) Biotechnology for production of fuels, chemicals, and materials from biomass. Journal of Applied Biochemistry and Biotechnology 39:3959

125. Xu DP, Madrid CP, Rohr M, Kubcek CP (1989). The influence of type and concentration of carbon source on production of citric acid by Aspergillus niger. Appl. Microbiol. Biotechnol. 30:553-558.

126. Zeikus JG, Jain MK, Elankovan P. (1999). Biotechnology of succinic acid production and markets for industrial products. Appl Microbiol Biotechnol, 51:545-552.

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Utilization of Food Wastes for Sustainable Development