MICROBES IN THE PRODUCTION OF BIOGAS
$\displaystyle \small \bullet$ Biogas is a mixture of gases (containing predominantly methane) produced by the microbial activity. Certain bacteria grow anaerobically on cellulosic material and produce large amount of methane along with $\displaystyle \small CO_{2}$ and $\displaystyle \small H_{2}$ which are collectively called as methanogens.
$\displaystyle \small \bullet$ One common methanogen is Methanobacterium. These bacteria are commonly found in the anaerobic sludge during sewage treatment and in the rumen of cattle to digest cellulose in the food of the cattle, thus the excreta of cattle, commonly called gobar can be used for generation of biogas, commonly called gobar gas.
$\displaystyle \small \bullet$ Biogas plant
$\displaystyle \small \circ$ The biogas plant consists of a concrete tank (10-15 feet deep) in which bio-wastes are collected and a slurry of dung is fed.
$\displaystyle \small \circ$ A floating cover is placed over the slurry, which keeps on rising as the gas is produced in the tank due to the microbial activity.
$\displaystyle \small \circ$ The biogas plant has an outlet, which is connected to a pipe to supply biogas to nearby houses.
$\displaystyle \small \circ$ The spent slurry is removed through another outlet and may be used as fertilizer.
$\displaystyle \small \circ$ The biogas thus produced can be used for cooking and lighting.
MICROBES AS BIOCONTROL AGENTS
$\displaystyle \small \bullet$ Biocontrol refers to the use of biological methods for controlling plant diseases and pests.
$\displaystyle \small \bullet$ Chemicals, insecticides and pesticides are extremely harmful to human beings and also these pollute our environment.
$\displaystyle \small \bullet$ The use of biocontrol measures will greatly reduce our dependence on toxic chemicals and pesticides.
$\displaystyle \small \bullet$ Biocontrol agents are which are useful in controlling plant diseases and pests are:
$\displaystyle \small \circ$ The ladybird, a beetle with red and black markings and dragon flies are useful to get rid of aphids and mosquitoes respectively.
$\displaystyle \small \circ$ Bacteria Bacillus thuringiensis (Bt) is used to get rid of butterfly caterpillars where dried spores of Bacillus thuringiensis are mixed with water and sprayed onto vulnerable plants such as brassicas and fruit trees and these are eaten by the insect larvae and in the gut of the larvae, the toxin is released and the larvae get killed.
$\displaystyle \small \circ$ Trichoderma species are free-living fungi found in the root ecosystem these are effective as biocontrol agents of several plant pathogens.
$\displaystyle \small \circ$ Baculoviruses are pathogens that attack insects and other arthropods and the majority of baculoviruses used as biological control agents are in the genus Nucleopolyhedrovirus.
MICROBES AS BIOFERTILIZERS
$\displaystyle \small \bullet$ Biofertilizers are organisms that enrich the nutrient quality of the soil.
$\displaystyle \small \bullet$ The main sources of biofertilizers are bacteria, fungi and cyanobacteria.
$\displaystyle \small \bullet$ Some microbes used as biofertlizers are:
$\displaystyle \small \circ$ Rhizobium form root nodules in leguminous plants and fix atmospheric nitrogen into organic forms, which is used by the plant as nutrient.
$\displaystyle \small \circ$ Free living bacteria like Azospirilium and Azotobacter fix atmospheric nitrogen, hence increases nitrogen content of the soil.
$\displaystyle \small \circ$ Many members of the genus Glomus form Mycorrhiza, which is the symbiotic association of fungi with roots of the plants.
$\displaystyle \small \bullet$ The fungal symbiont in these associations absorbs phosphorus from soil and passes to the plants. Plants having symbiotic association show resistance to root-borne pathogens, tolerance to salinity and drought, and an overall increase in plant growth and development.
$\displaystyle \small \bullet$ Cyanobacteria are autotrophic microbes which can fix atmospheric nitrogen.
$\displaystyle \small \bullet$ Example - Anabaena, Nostoc, Oscillatoria
$\displaystyle \small \bullet$ Blue green algae also add organic matter to the soil and increase its fertility.
$\displaystyle \small \bullet$ Biogas is a mixture of gases (containing predominantly methane) produced by the microbial activity. Certain bacteria grow anaerobically on cellulosic material and produce large amount of methane along with $\displaystyle \small CO_{2}$ and $\displaystyle \small H_{2}$ which are collectively called as methanogens.
$\displaystyle \small \bullet$ One common methanogen is Methanobacterium. These bacteria are commonly found in the anaerobic sludge during sewage treatment and in the rumen of cattle to digest cellulose in the food of the cattle, thus the excreta of cattle, commonly called gobar can be used for generation of biogas, commonly called gobar gas.
$\displaystyle \small \bullet$ Biogas plant
$\displaystyle \small \circ$ The biogas plant consists of a concrete tank (10-15 feet deep) in which bio-wastes are collected and a slurry of dung is fed.
$\displaystyle \small \circ$ A floating cover is placed over the slurry, which keeps on rising as the gas is produced in the tank due to the microbial activity.
$\displaystyle \small \circ$ The biogas plant has an outlet, which is connected to a pipe to supply biogas to nearby houses.
$\displaystyle \small \circ$ The spent slurry is removed through another outlet and may be used as fertilizer.
$\displaystyle \small \circ$ The biogas thus produced can be used for cooking and lighting.
MICROBES AS BIOCONTROL AGENTS
$\displaystyle \small \bullet$ Biocontrol refers to the use of biological methods for controlling plant diseases and pests.
$\displaystyle \small \bullet$ Chemicals, insecticides and pesticides are extremely harmful to human beings and also these pollute our environment.
$\displaystyle \small \bullet$ The use of biocontrol measures will greatly reduce our dependence on toxic chemicals and pesticides.
$\displaystyle \small \bullet$ Biocontrol agents are which are useful in controlling plant diseases and pests are:
$\displaystyle \small \circ$ The ladybird, a beetle with red and black markings and dragon flies are useful to get rid of aphids and mosquitoes respectively.
$\displaystyle \small \circ$ Bacteria Bacillus thuringiensis (Bt) is used to get rid of butterfly caterpillars where dried spores of Bacillus thuringiensis are mixed with water and sprayed onto vulnerable plants such as brassicas and fruit trees and these are eaten by the insect larvae and in the gut of the larvae, the toxin is released and the larvae get killed.
$\displaystyle \small \circ$ Trichoderma species are free-living fungi found in the root ecosystem these are effective as biocontrol agents of several plant pathogens.
$\displaystyle \small \circ$ Baculoviruses are pathogens that attack insects and other arthropods and the majority of baculoviruses used as biological control agents are in the genus Nucleopolyhedrovirus.
MICROBES AS BIOFERTILIZERS
$\displaystyle \small \bullet$ Biofertilizers are organisms that enrich the nutrient quality of the soil.
$\displaystyle \small \bullet$ The main sources of biofertilizers are bacteria, fungi and cyanobacteria.
$\displaystyle \small \bullet$ Some microbes used as biofertlizers are:
$\displaystyle \small \circ$ Rhizobium form root nodules in leguminous plants and fix atmospheric nitrogen into organic forms, which is used by the plant as nutrient.
$\displaystyle \small \circ$ Free living bacteria like Azospirilium and Azotobacter fix atmospheric nitrogen, hence increases nitrogen content of the soil.
$\displaystyle \small \circ$ Many members of the genus Glomus form Mycorrhiza, which is the symbiotic association of fungi with roots of the plants.
$\displaystyle \small \bullet$ The fungal symbiont in these associations absorbs phosphorus from soil and passes to the plants. Plants having symbiotic association show resistance to root-borne pathogens, tolerance to salinity and drought, and an overall increase in plant growth and development.
$\displaystyle \small \bullet$ Cyanobacteria are autotrophic microbes which can fix atmospheric nitrogen.
$\displaystyle \small \bullet$ Example - Anabaena, Nostoc, Oscillatoria
$\displaystyle \small \bullet$ Blue green algae also add organic matter to the soil and increase its fertility.
0 Comments