Biohydrogen Production From POME-libre

8/10/2019 Biohydrogen Production From POME-libre

1/24

BIOTECH SBE UISC 2014

Biohydrogen Production from POME: The Answer For Future

Energy Independence Of Indonesia

Proposed by:

Muhamad Zaid (11211040)

Sendi Ramdhani (13011501)

Pramesti Istiandari (11211004)

Hamdin Kifahul Muhajir (11212016)

BANDUNG INSTITUTE OF TECHNOLOGY

BANDUNG

2014


2/24

i


3/24

ii

PREFACE

First of all, praise and thanksgiving prayed to God because for all his gifts so we

can finished this paper entitled Biohydrogen from POME: The Answer for

Future Energy Independence of Indonesia ". in writing this paper, the authors

collected material with literature study and interviewed the lecturer. So we would

like to say thank you to Mr. Dr. Indra Wibowo as our advisor who has gave us

some advices to complete this paper. And to our family and our friends who have

provided moral and material support. And to all the parties that can not be

mentoined one by one that has made this paper can be realized.

The authors realizes that this paper is stil not perfect. Therefore, criticism and

constructive suggestions for improving this paper is expected. Hopefully this

paper can be usefull for all those in need.

Bandung, September 2014

Authors


4/24

iii

CONTENTS

HALAMAN PENGESAHAN.............................................................................................. i

PREFACE........................................................................................................................... ii

CONTENTS....................................................................................................................... iii

LIST OF TABLES ..............................................................................................................iv

LIST OF FIGURE............................................................................................................... v

ABSTRACT ........................................................................................................................vi

I.INTRODUCTION........................................................................................................... 1

II.LITERATURE REVIEW............................................................................................... 3

HYDROGEN ENERGY................................................................................................. 3

PRODUCTION OF BIOHYDROGEN.......................................................................... 5

Direct Biophotolysis................................................................................................... 5

Indirect Biophotolysis................................................................................................. 6

Dark Fermentation...................................................................................................... 7

Biological Water-Gas Shift Reaction.......................................................................... 8

Photo Fermentation..................................................................................................... 8

Integrated Process....................................................................................................... 9

III.WRITING METHOD................................................................................................. 11

IV.DISCUSSION............................................................................................................. 12

V.CLOSING.................................................................................................................... 16

VI.REFERENCE.............................................................................................................. 17


5/24

iv

LIST OF TABLES

Table 1 Comparison of H2 production by different methods ................................. 5

Table 2 Yield of biohydrogen using POME ......................................................... 12Table 3 Potential of Biohydrogen production from POME in Indonesia ............. 14


6/24

v

LIST OF FIGURE

Figure 1. Hydrogen Fuel Cell (images adapted from h-tec.com)............................ 3

Figure 2 Two photo and one dark combination process of biohydrogenproduction.............................................................................................................. 10


7/24

vi

ABSTRACT

In 2014, energy demand of Indonesia is reported to be 933.3 million BOE (barrel

of oil equivalent), and only 23.9% from this amount that can be supplied from

national oil and gas production. This condition gets worse by the continually

increase in energy demand up to 7.1% every year and our oil and gas reserve is

declining significantly over this last ten years. This dependency of unrenewable

sources and environmentally unfriendly emission reaffirm the urgency for

government to consider potential renewable source of energy to fulfill Indonesias

needs in the future. One of the potential renewable energy sources is biohydrogen

production from palm oil mill effluent (POME). POME is the waste of palm oil

process which can produce 2-4 times bigger than the production of the crude palm

oil itself. The utilization of POME that has not been commercially available might

create a long-term prospect in industry of bioconversion.

Research related to the production of biohydrogen from POME using

microorganism had been widely performed, one of which was through dark

fermentation pathway, which had been reported to have the highest production

efficiency. Unfortunately, this option of renewable energy still has limitation to be

applied to industrial scale. This is due to the relatively higher production cost

compare to its profit from biohydrogen production. Therefore, further study is

needed to be able produce biohydrogen from POME up to commercial level. The

purpose of writing this paper is to analyze the long-term prospect of the

production of biohydrogen from POME which is reviewed from its bioreactor

design, process modification, and along with factors affecting its economic profit.

Hopefully this paper can point out some recommendations in biohydrogen

industry from palm oil waste to become an answer for the independence of energy

of Indonesia in the future.

Keywords: Renewable energy, Biohydrogen, Palm Oil Mill effluent


8/24


9/24

2

harmfull to the environment. Therefore, we have to do significant efforts and

think strategically to answer the energy problem. One of its efforts is to find the

renewable energy that are environmentally friendly (green energy) and replace

petrochemical materials with materials from biomass.

The researcher have developed a bio-ethanol as an alternative to fossil fuel. And

now it has come to the development of third-generation bioethanol using

microalgae as a medium. but there are still some weakness in the development of

bioethanol is that in terms of fuel efficiency is still lacking and too many bad

impact on the environment (Karyati et al, 2011).

One of potential energy resources in addressing these two issues is biohydrogen.

Biohidrogen is the process to produce hydrogen biologically, for example by

using microorganisms. And the hydrogen is a material with an infinite number

unversal in nature and can be produced forever. Molecular H2 has the highest

energy content per unit weight among the known gaseous fuels (143GJton1) [1]

and is the only carbon-free fuel which ultimately oxidizes to water as a

combustion product. Therefore burning hydrogen not only has the potential to

meet a wide variety of end use applications but also does not contribute to

greenhouse emis-sion, acid rain or ozone depletion (Kotay and Das, 2008:258).

In Indonesia one of the most well biohidrogen development and realistic that is

with biohidrogen produced from Palm oil mill effluent (POME). Because POME

abundant in Indonesia, especially Kalimantan area there is lots of palm oil

processing. POME is a waste of processing palm oil that can be produced 5-6

times greater than the production of palm oilnya own. And there is no utilization

of POME developed commercially by the prospect of a long Bioconversion world.

Many of the researchers and engineer have discovered various methods in

wastewater treatment pome become biohydrogen. However, some are less feasible

to do even loss when viewed from an industrial scale. Therefore, this paper will

discuss some methods of bioreactor design and processing biohidrogen POME

which is realistic and can be developed in the industrial scale.


10/24

3

II. LITERATURE REVIEW

HYDROGEN ENERGY

Hydrogen gas was first artificially produced in the early 16th century, via the

mixing of metals with acids. In 176681, Henry Cavendish was the first to

recognize that hydrogen gas was a discrete substance, and that it produces water

when burned. Based on this work, other development shows that the combustion

of hydrogen can produce electricity which is potential to be an energy source in

the future. The picture shown below, explain how hydrogen gases produce

electricity within a fuel cell.

Figure 1. Hydrogen Fuel Cell (images adapted from h-tec.com)

Nevertheless, hydrogen is an energy carrier, like electricity, not a primary energy

resource. Energy firms must first produce the hydrogen gas, and that production

induces environmental impacts. Hydrogen production always requires more

energy than can be retrieved from the gas as a fuel later on. This is a limitation of

the hydrogen production. However, many research has been done to review


11/24

4

hydrogen production method consider to environmental concerns, energy usage,

and socioeconomic issues. The following below are several ways to produce

hydrogen gases:

1.Steam reforming

Steam reforming is currently the least expensive and most common method to

produce hydrogen. It can be applied to generate hydrogen from natural gas or

from other hydrocarbons with approximately 80% efficiency. However,

disadvantages of this process is some amount of carbon dioxide will be

released, if CO2 were to be captured, an additional separation step would be

needed.

2.Electrolysis

Providing clean hydrogen with no carbon and sulphur contamination is one of

the advantages of this method. However, electrolysis has some disadvantages

such as its higher cost and energy needs than the fossil fuel alternatives, It

because of the hydrogen production process needs electricity trough water to

separate hydrogen and oxygen atoms. Furthermore, electrolysis offers a way to

produce hydrogen with electrical power generated from renewable resources

like solar, wind, hydropower to provide electricity.

3.Gasification

Gasification is a thermo-chemical process in which carbonaceous (carbon-rich)

feedstocks such as coal, petro-coke or biomass are converted into a gas

consisting of hydrogen and carbon monoxide under oxygen depleted, high

pressure, high-heat and/or steam conditions. One of the drawbacks of

gasification method is numerous energy needs to create a proper condition

during this process.

In addition to the methods above, pure hydrogen gases can also be produce based

on biomass or biological methods. This methods presumed as an alternative and

renewable bioenergy resource of hydrogen with low energy and high efficiency,

thereby being considered a promising way of producing hydrogen (Ganesh D.,

2013), therefore, biological hydrogen production methods will be specially

reviewed in the next chapter.


12/24

5

PRODUCTION OF BIOHYDROGEN

The biological method applies microorganism to converting the organic matter

into usable hydrogen through their capabilities to produce various potentialenzymes. This method does not only solve the problem of environmental pollution

but also develops clean hydrogen energy and is an economic and competitive

method of hydrogen production (Hsia and Chou, 2014). Processes for biological

hydrogen production mostly operate at ambient temperatures and pressures, and

are expected to be less energy intensive than thermochemical methods of

hydrogen production. Hydrogen can be produced biologically by biophotolysis

(direct and indirect), biological water-gas shift reaction, photo-fermentation and

dark-fermentation or by a combination of these processes (Manish and Banerjee,

2007).

Table 1. Comparison of H2 production by different methods

Direct Biophotolysis

The natural ability of photosynthetic microorganisms like green algae to capture

solar energy and split water has created an alternative way to produce

biohydrogen. They can convert light energy into chemical energy as:

2H2O + light energy = 2 H2 + O2

The most commonly used green algae for biophotolysis is Chlamydomonas

reinhardtii. The hydrogenase enzyme of the green algae combines protons (H+) in

the medium with electrons to form and release H2(Levin et al, 2004). The rate of


13/24

6

H2production by C. reinhardtii reportedby Kosourov et al. Was 7.95 mmol H2/l

of culture or similar to 0.07 mmole of H2/l/h.

H2production by this method is considered simpler because it only needs sunlight

as energy source and theoretical solar energy conversion can achieve 80% (Sen et

al, 2008). The algal hydrogen production also could be considered as an

economical and sustainable method in terms of water utilization as a renewable

resource and CO2 consumption as one of the air pollutants (Kapdan and Kargi,

2006). However, in actual practice, the efficiency of H2production by this method

is low (Sen et al, 2008) and at high solar intensities, the photosynthesis activity

may utilise too much photons that can result in dissipation and loss of photons as

heat. No waste utilization is also a disadvantage of hydrogen production by algae

(Kapdan and Kargi, 2006).

The main problem of this method is that the activity of hydrogenase enzyme is

highly sensitive to O2 presence, which is the main product of the reaction.

Therefore the production of H2 and O2 must be temporally and/or spatially

separated which includes an incubation of microalgae anaerobically in a sulphur-

free medium.

Indirect Biophotolysis

Cyanobacteria has the simplest nutritional requirement of using CO2 in the air as a

carbon source and solar energy as an energy source. The cells take up CO2first to

produce cellular substances, which are subsequently used for hydrogen

production, with the overall reaction as below (Manish and Banerjee, 2008):

12H2O + 6CO2+ light energy C6H12O6+ 6O2

C6H12O6+ 12H2O + light energy 12H2+ 6CO2

Species of cyanobacteria may possess nitrogenases to reduce ammonia and

hydrogenase to produce H2. Commonly used cyanobacteria are Anabaena,


14/24

7

Oscillatoria, Calothrix, and Gloeocapsa. Levin et. al. (2004) reviewed that

maximum of 4.2 mol H2/mg chl a/h of H2production was get from Anabaena

variablilis. In other study with nitrogen strarvation medium, the rate of H2

synthesis can be achieved to 12.6 mol/g protein/h that is equal to 0.355 mmol

H2/l/h. Despite of the benefit of the process, maximum light conversion efficiency

for this process is 16.3%, and higher in low light illumination, but in actual

practice, the efficiency is only 1-2% (Sen et al, 2008)

Dark Fermentation

Bacteria known to produce hydrogen include species of Enterobacter, Bacillus,

Clostridium, and mixed Microflora. Carbohydrates are the preferred substrate.

When acetic acid or butyrate is the end-product, it obtains theoretical maximum of

4 or 2 mole H2 per mole of glucose respectively. But in the laboratory

experiment, only maximum yield of 3.2 moles H2/moles substrate has been

achieved (Sen et al, 2008). Levin et al (2004) reviewed that hydrogen production

in order of 121 mmol H2/l/h achieved during mesophilic dark fermentation.

Dark fermentative hydrogen production is economically feasible because of

higher hydrogen production rate and lower doubling time of the microbes than in

the photo fermentation and biophotolysis. Dark fermentation processes result in

huge amount of hydrogen production using different types of organic wastes

(Urja, 2014). The feasibility of the technology may yield a growing commercial

value because it does not need light, wide land, and therefore not affected by

weather (Road2HyCom, 2014).

Sen et al (2008) stated that eventhough rate and yield of dark fermentation process

are more than the others, the H2 concentration is very low (40-60%, v/v). The

amount of hydrogen production by dark fermentation highly depends on the pH

value, hydraulic retention time (HRT) and gas partial pressure. When pH

increases, the metabolic pathways shift to produce more reduced substrates, which

in turn decrease the hydrogen production (Roads2HyCom, 2014). Large


15/24

8

quantitites of side products like organic acids produced then becomes a concern

and further treatment is then needed (Hallenbeck et al, 2012).

Biological Water-Gas Shift Reaction

This method uses Rhodospillaceae to grow in the dark and using CO as carbon

source. The oxidation of CO to CO2 with the release of H2 occurs via a watergas

shift reaction:

CO(g) + H2O(l) CO2(g) + H2(g)

The reaction is mediated by proteins coordinated in an enzymatic pathway. The

reaction takes place at low temperature and pressure.Thermodynamics of the

reaction are very favorable to CO-oxidation and H2synthesis since the

equilibrium is strongly to the right of this reaction. In his review, Levin et al

(2004) also stated that H2production rate by this method was found to be 96

mmol H2/l/h using R. gelatinosus. The maximum hydrogen production activity

also was found to be 27 mmol/g cell/h, which is about three times higher than R.

rubrum (Road2HyCom, 2014).

Photo Fermentation

Purple photosynthetic bacteria such as Rhodobacter, Rhodopseudomonas, and

Rhodospirillum (Sen et al, 2008) are capable of converting organic acids (acetic,

lactic, and butyric) to hydrogen (H2) and carbon dioxide (CO2) under anaerobic

condition in the presence of light. Nitrogenase is the key enzyme that catalyzes

the production of the hydrogen gas which is inhibited by the presence of oxygen,

ammonia, or high nitrogen-to-carbon ratios (Kapdan and Kargi, 2006). The

preferred substrate is acetic acid whose electrons are transported to the

nitrogenase by ferredoxin using ATP as energy drive. (Manish and Banerjee,

2008).


16/24

9

Production of H2 by photosynthetic bacteria is affected by light intensity,

wavelength, and illumination protocol (Sen et al, 2008). Thus, the main limiting

factors that prevent practical application of photo fermentation are the overall low

light conversion efficiencies, the inability to use full solar light effectively, low

volumetric rates of hydrogen production, and the low yields observed with some

substrates (Hallenbeck, 2012)

Theoretically, H2 production from one mol of acetic acid, propionic acid, and

butyric acid are 4, 7, 10 mol respectively, but in actual practice, H2 yields are only

1.6, 2.8, and 4.0 mol (reviewed by Sen et al, 2008). It has been investigated that

H2from sugar cane juice yielded maximum level of hydrogen production with 45

mL/mg dry weight/h through photo fermentation process (Kapdan and Kargi,

2006).

Integrated Process

Complete oxidation of glucose into hydrogen and carbon dioxide is not possible

as the corresponding reaction is not feasible thermodynamically (Go =+3.2 kJ).

Therefore dark fermentation which produces organic acids such as acetic acid is

then followed by photo fermentation that oxidizes it into hydrogen. The overall

reaction is as below (Manish and Banerjee, 2008):

C6H12O6+ 2H2O 4H2 + 2CO2+ 2CH3COOH Go =206 kJ

CH3COOH + 2H2O + light energy 4H2+ 2CO2 Go =+104 kJ

As reviewed by Kapdan and Kargi (2006), sequential dark-photo fermentation can

produce up to 110 mL/g dry weight/h.

A three-steps integrated process has been reviewed by Sen et al (2008) that starts

at producing biomass from Chlamydomonas, then the feedstock (starch) is

fermented by Clostridium to produce acetate which then oxidized by Rhodobacter

to produce H2.


17/24

10

Combining green algae which absorbs visible light and photosynthetic bacteria

which absorbs the infrared of solar radiation, increases the overall light

conversion efficiency. Malis et al successfully combines Chlamydomonas

reinhardtii and Rhodospirillum rubrum. This system would create high yield and

more economically viable H2.

Figure 2. Two photo and one dark combination process of biohydrogen production

(adapted from Sen et al, 2004)


18/24

11

III. WRITING METHOD

The method used in the writing of this scientific paper is a literature review begins

with a feasibility study on biohydrogen from palm oil waste as an alternative

energy in the future. This section begins by looking for any methods that allow for

the production of biohydrogen from POME. Furthermore, the production methods

that have been found based on existing studies, selected one of the most effective

and efficient by considering the possible extension to the industrial scale.

In the discussion section, total amount of energy that can be produced from

biohydrogen from POME waste in Indonesia also studied using mathematicalapproach. This calculation method starts by searching data production Crude Palm

Oil (CPO) in the entire POM (Palm Oil Mill) in Indonesia. furthermore, from this

result will be obtained amount of waste production POME (Palm Oil Mill

Effluent) by calculating the ratio of national standards in the production of waste

oil per tonne of CPO. Then the total production POME per year will be used to

determine the amount of biohydrogen that can be produced from the method that

has been chosen by considering the yield of production biohidrogen based studies

that has been done. The total energy produced will be a consideration of whether

the biohydrogen industry from palm oil wastewater is potential for long-term

development.


19/24

12

IV. DISCUSSION

BIOHYDROGEN PRODUCTION METHOD

POME has a very high BOD and COD, which is 100 times more than the

municipal sewage. POME is a non-toxic waste, as no chemical is added during the

oil extraction process, but will pose environmental issues due to large oxygen

depleting capability in aquatic system due to organic and nutrient contents. The

high organic matter is due to the presence of different sugars such as arabinose,

xylose, glucose, galactose and manose. The suspended solids in the POME are

mainly oil-bearing cellulosic materials from the fruits. Since the POME is non-

toxic as no chemical is added in the oil extraction process, it is a good source of

nutrients for microorganisms.

Table 2 Yield of biohydrogen using POME

From all the methods for producing biohydrogen, dark fermentation is preferred

for biohydrogen production from POME in Indonesia. Fermentation process using

anaerobic bacteria is considered much simpler in the process of biohydrogen

production. Dark fermentation is chosen because of its high hydrogen yield per

volume of medium compare to the other method. The fermentative process is also


20/24

13

more stable than photofermentation, which is only mainly affected by pH and

HRT. The combination of the two fermentation method has been proven to

produce higher yield, but also require higher cost and power consumption

throughout the process. Therefore this paper only focuses on the dark

fermentation process.

The seed microorganisms such as Clostridium or microflora for hydrogen

production was enriched from anaerobic sludge collecting from palm oil mill

wastewater treatment plant. The sludge was settled and collected after decanting

the supernatant. Seed microoganism was prepared by certain shock pre-treatment

to remove methanogenic bioactivity (O-Thong et al, 2009). Sludge wassubsequently enriched in a synthetic medium and the initial pH value was adjusted

to 5.5 (Fan et al, 2004). The sludge needs to be acclimatised gradually by

increasing the concentration of the POME. Acclimatised POME sludge was

employed for hydrogen fermentation using fresh raw POME and enzyme treated

POME (or hydrolysed POME). Hydrolysed POME basically contains monomeric

sugars which are favourable for microbial growth (Khaleb et al, 2011). The

POME sludge was kept at 0-4C before use.

The evolved hydrogen gas was collected. Usually, The biogas evolved was

collected in inverted graduated cylinder using water displacement method. Gas

chromatography is then used to determine the composition of the biogas. The

corresponding values of specific hydrogen production (Ps ) and hydrogen

production potential (P) were obtained by fitting with modified Gompertz

equation (Lay et al, 1999). R2for all parameters was larger than 0.95, indicating

that the parameters were statistically significant.

Where, H(t) (ml) = represents the cumulative volume of hydrogen production, P

(ml) = the hydrogen production potential, Rm(ml/h) = the maximum production

rate, and (h) = the lag time.
http://www.ejbiotechnology.info/index.php/ejbiotechnology/article/view/v14n5-9/1361#25http://www.ejbiotechnology.info/index.php/ejbiotechnology/article/view/v14n5-9/1361#8http://www.ejbiotechnology.info/index.php/ejbiotechnology/article/view/v14n5-9/1361#14http://www.ejbiotechnology.info/index.php/ejbiotechnology/article/view/v14n5-9/1361#14http://www.ejbiotechnology.info/index.php/ejbiotechnology/article/view/v14n5-9/1361#14http://www.ejbiotechnology.info/index.php/ejbiotechnology/article/view/v14n5-9/1361#8http://www.ejbiotechnology.info/index.php/ejbiotechnology/article/view/v14n5-9/1361#25


21/24

14

Enriched microorganism and optimum condition from batch tests and semi-

continuous were applied to continuously hydrogen production from POME. The

temperature was controlled at 60C by circulating hot water inside the water

jacket of the reactors. Mixing was provided by a magnetic stirrer located

underneath the reactor. The initial anaerobic condition in the reactor was

established by replacing the gaseous phase with oxygen free nitrogen. The POME

was continuously pumped into reactors. The amounts of evolved gas, soluble

metabolites, and responsible microbial community were investigated. The reactors

were operated until the system reached steady state. The steady-state condition

was reached when hydrogen gas content, biogas volume and the volatile fatty

acids (VFA) concentration in the effluent were stable (less than 10% variation) for

a week (O-Thong et al, 2011).

Table 3 Potential of Biohydrogen production from POME in Indonesia

Process Quantity Unit Source

Indonesias Palm

Cultivation

Palm Oil Production 31000000 ton/yr

www.pecad.fas.usda.gov

(2013)

Palm Oil Cultivation Area 10800000 hectareswww.pecad.fas.usda.gov

(2013)

FFB (fresh fruit bunch)yield 18.8 ton/ha/yr

outputs.worldagroforestry.org(2014)

POME from FFB 0.65 m3/ton FFB King and Yu (2013)

FFB per year 203040000 ton

POME per year 131976000 m3

Average H2 production

from dark fermentation

process

4500 ml H2/L POME

Lam and Lee (2010)

Hydrogen production 5.93 x 1014 mL H2/yearDensity hydrogen 0.0899 kg/m3

53.39 x 106 kg H2/year

Energy from hydrogen 122000000 J/kg Saratale et al (2008)

6513 x 1012 J/year

Total energy from

hydrogen 1,064,000

BOE (Barrel of

Oil Equivalent)


22/24

15

From the mathematical analysis above, we know that biohydrogen production

from POME especially in Indonesia, has the potential to produce energy annually

around one million BOE. Furthermore, this number is much smaller than gasoline

deficiency in Indonesia. Although the amount of energy generated from

biohydrogen is still relatively small, biohydrogen production from palm oil waste

still has long-term potential is quite promising due to the growth of palm oil

industry in Indonesia is very fast and needs of energy sources that are

environmentally friendly for the big cities is exigent. Moreover, hydrogen

combustion through fuel cells is more efficient producing useable energy than

gasoline combustion (David Roper, 2006). Hydrogen Energy Systems LLC

mentions that 1 kg of hydrogen (1 GGE) can travel a distance of 81 miles when 1

GGE of gasoline only able to cover up to 31 miles. Latter, hydrogen is a carbon-

free fuel, so, its use in replacing gasoline would much reduce carbon emissions in

the air and keep the air clean even in the big cities. Based on the reasons stated

above, it is clear that biohidrogen production from POME is promising bioprocess

industry in the future, especially in the field of renewable and clean energy.


23/24

16

V. CLOSING

In this recent time, biohydrogen production from Palm Oil Mill Effluent not yet

be able to solve the energy independent in Indonesia. Further research is needed toproduce biohydrogen with higher efficiency. The next challenge is how to supress

the high cost in industry of biohydrogen production due to the required

sophisticated infrastructure for this process. This industry will not be able to start

without any collaboration with government, investors, and companies which

actually should become the solution to environment issues in big cities.

Amount of energy that can be produced from biohydrogen industry from palm

sewage also will be increased gradually along with the fast growing palm industry

in Indonesia, especially in Sumatera and Kalimantan island. Therefore, attention

from the central government to the potential of this industry is very much needed

for it to become the new source of renewable energy.


24/24

VI. REFERENCE

Kotay, SM., Das, D. 2008. Biohydrogen as renewable energy resource-Prospect

and Potential. International Journal of Hydrogen Energy : 258-263.

Karyati Y, et al. 2011. Manajemen dan Konservasi Energi : Analisa Biohidrogen.

Essay. Program Sarjana Universitas Diponegoro. Semarang.

Hallenbeck, et. al. 2012. Stra tegies for improving biological hydrogen production.

Bioresource Technology. 110 (2012): 19

Kapdan, I. K. and Kargi, F. 2005. Biohydrogen production from waste material.

Enzyme and Microbial Technology. 38 (2006): 569582

Khaleb, et. al. 2011. Biohydrogen Production Using Hydrolysates of Palm Oil

Mill Effluent (POME). Journal of Asian Scientific Research. 2 (11): 705 710

Khanna, N. and Das, D. 2012. Biohydrogen production by dark fermentation.

John Wiley & Sons, Ltd. 00: 1-21.

Lam, M. K. and Lee, K. T. 2011. Renewable and sustainable bioenergies

production from palm oil mill effluent (POME): Winwin strategies toward better

environmental protection. Biotechnology Advances. 29 (2011): 124141

Levin, et. al. 2003. Biohydrogen production: prospects ad limitations to practicalapplication. International Journal of Hydrogen Energy. 29 (2004): 173185

Manish, S. and Banerjee, R. 2007. Comparison of biohydrogen production

processes. International Journal of Hydrogen Energy. 33 (2008) : 279286

O-Thong, S. 2011. Effect of temperature and initial pH on biohydrogen

production from palm oil mill effluent: long-term evaluation and microbial

community analysis. Electronic Journal of Biotechnology. 14 (5)

Saratale, et. al. 2008. Outlook of biohydrogen production from lignocellulosic

feedstock using dark fermentation a review. Journal of Scientific & Industrial

Research. 67 (2008): 962979

Sen, et. al. 2008. Status of Biological hydrogen production. Journal of Scientific

& Industrial Research. 67 (2008): 980993

Urja A. 2014. Biomass to Biohydrogen: A Successful Path. RE Feature

Documents

Biohydrogen Production From POME-libre