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Decomposition of dead organic remains is carried out by a group of saprophytic bacteria and fungi, which are called decomposers.
Decomposers break down the dead remains of plants and animals and waste products of animals and release nutrients into the soil.
BACTERIABACTERIA
FUNGIFUNGI
Nitrogen is an important element in the synthesis of plant and animal
proteins.
Atmospheric nitrogen cannot be absorbed directly by plants. Plants can only absorb nitrogen
in the form of ammonium, nitrite or nitrate ions.
Nitrates, in particular, are taken up by the roots of
plants and converted into plant proteins.
When the animals eat the plants, the organic nitrogen is transferred into the body of animals
and becomes animal proteins.
Nitrogen fixing bacteria such as Nostoc sp. , which lives freely in the soil, and Rhizobium sp. which lives in
the root nodules of leguminous plants, can convert atmospheric
nitrogen into ammonium compounds (NH3 and NH4 ) through a
process called nitrogen fixation.
NH3
Waste matter, and plants and animals which die, decompose and are
converted into ammonium compounds.
Ammonium compounds are converted into nitrites and
nitrates by nitrifying bacteria through a process called
nitrification.Ammonia is converted into
nitrites (NO2−) by Nitrosomona sp.
Nitrites are converted into nitrates (NO3-) by Nitrobacter
sp.
The cycle is balanced by a continuous return of nitrogen to the atmosphere by denitrifying bacteria. These bacteria break
down nitrates and release nitrogen back into the atmosphere.
Nitrobacter sp. Nitrobacter sp.
Microorganisms also play an important
role in the alimentary
canal of termites.
Population of mutualistic protozoans such as
Trichonympha sp. are present in the alimentary
canal of termites. They secrete cellulase which is
required by the termites to digest cellulose.
Termites feed mainly on wood which
contains cellulose. However, they are
unable to produce the enzyme cellulase to digest the cellulose.
Trichonympha sp.
Useful symbiotic bacteria are found in the human colon. The useful microorganisms
synthesise vitamins B12 and K which are often deficient in
the human diet.
ANTIBIOTICS
Poliomyelitis is a viral disease that can affect nerves and can lead to partial or full paralysis.
a. Sewage is the waste matter from households
and industries.
b. It is reach in organic matter, bacteria and other microorganisms.
c. Sewage from various households & industries is piped into large settling tanks in sewage treatment plants.
d. During the waste treatment process, millions of aerobic bacteria present in the sewage decompose organic matterin the presence of oxygen.
e. Most of the sludge that settles at the bottom of settling
tanks is pumped into the sedimentation tanks where fermentation takes place.
e. Most of the sludge that settles at the bottom of settling
tanks is pumped into the sedimentation tanks where fermentation takes place.
f. Here, anaerobic bacteria continue to decompose
the organic matter to methane & carbon dioxide, along with water & other
minerals.
f. Here, anaerobic bacteria continue to decompose
the organic matter to methane & carbon dioxide, along with water & other
minerals.
g. The methane gas is collected & used as fuel for
the engine pumps in the sewage plants
g. The methane gas is collected & used as fuel for
the engine pumps in the sewage plants
h. The digested sludge is rich in
nitrates & phosphates and
when it is dried it can be used as
fertilizers by farmers.
h. The digested sludge is rich in
nitrates & phosphates and
when it is dried it can be used as
fertilizers by farmers.
SLUDGE
The commercial use of microorganisms in food processing is based on the process of fermentation.
Fermentation is a metabolic process whereby electrons released from nutrients are ultimately transferred to molecules obtained from thebreakdown of those same nutrients
Fermentation is a metabolic process whereby electrons released from nutrients are ultimately transferred to molecules obtained from thebreakdown of those same nutrients
YEAST
a) Beer is brewed from barley grains.b) In commercial beer-making, two commonly used yeast species are S. cerevisiae and S. carlsbergensis (brewer yeast).
a) Beer is brewed from barley grains.b) In commercial beer-making, two commonly used yeast species are S. cerevisiae and S. carlsbergensis (brewer yeast).
a) Wine is made by the fermentation of grape juices.b) During fermentation, ethanol & carbon dioxide are released.
a) Wine is made by the fermentation of grape juices.b) During fermentation, ethanol & carbon dioxide are released.
Soy sauce is made from fermented soya beans by the action of fungi.
Soy sauce is made from fermented soya beans by the action of fungi.
S tS tL BL B
a) Yogurt is made from the fermentation of milk using bacteria, especially Lactobacillus bulgarius and Streptococcus thermophillus.b) These bacteria convert sugar into lactic acid which coagulates casein (milk protein).c) This creates the thick creamy yogurt
a) Yogurt is made from the fermentation of milk using bacteria, especially Lactobacillus bulgarius and Streptococcus thermophillus.b) These bacteria convert sugar into lactic acid which coagulates casein (milk protein).c) This creates the thick creamy yogurt
a) Cheese is made by mixing bacteria (etc, streptococcus sp.) with the enzyme rennin.b) The bacteria ferment milk sugar to lactic acid.c) The solid part of the milk (the curt) is separated from the liquid portion (the whey).d) The curds are pressed and moulded and then left to mature or ripen.
a) Cheese is made by mixing bacteria (etc, streptococcus sp.) with the enzyme rennin.b) The bacteria ferment milk sugar to lactic acid.c) The solid part of the milk (the curt) is separated from the liquid portion (the whey).d) The curds are pressed and moulded and then left to mature or ripen.
Rennin Strept
o-coccus
sp
a) BIOGASa) BIOGAS
Gasohol or biofuel is a combination of 10% ethanol and 90% petrol.
Sugar cane and maize are the main sources of gasohol. The cane or maize is crushed and sucrose is extracted to form a sweet syrup.
This syrup contains glucose and fructose which when left to ferment by adding yeast,will produce ethanol.The ethanol is distilled before it is used.
Gasohol is used widely as fuel or as an alternative to petrol in some countries.