Microbes In Human Welfare

Members of kingdom monera - bacteria and cyanobacteria (blue green algae) have the ability to fix nitrogen. Azotobacter is a N2-fixing bacteria. Anabaena and Nostoc are heterocystous blue-green algae. The heterocysts are the sites of N2-fixation. Spirogyra is one of the commonest green algae. It has no function in nitrogen fixation.

The control of insect pests by the introduction, encouragement and artificial increase of biological agencies like predaceous and parasitic insects, other animals and diseases is termed as biological control. It is basically a natural control in which man plays significant role of making the biological agencies more effective. It is a self perpetuating method as the organisms which act as biocontrol agent are able to grow and reproduce unlike chemical control agents.

Azotobacter are non-symbiotic, free living nitrogen fixing bacteria.

Citric acid is produced by aerobic fermentation of sucrose in beet molasses by Aspergillus niger. The fermentation process is completed in about 5-14 days at 27 - 33?C. Citric acid is made available in the market in the form of anhydrous crystalline chemical as powder. Citric acid is used in food industry (e.g. fruit drinks, confectionery, jams, jellies, preserved fruits), pharmacy (e.g. blood transfusion), consmetics (e.g. astringent lotions, shampoos and hair setting fluids), and industries (e.g. electroplating leather tanning).

Extensive growth of Opuntia (Cactus) in Australia was checked through introduction of its natural herbivore, cochineal insect (Cactoblastis cactorum).

Biofertilizers are organisms which bring about nutrient enrichment of the soil. Azotobacter is a free living, aerobic, nitrogen fixing bacteria. Anabena is a nitrogen fixing cyanobacteria that occurs in both free living and symbiote associations with Azolla, Cycas roots etc. Rhizobium lives symbiotically in root nodules of legumes and non-legumes. Vesicular-arbuscular mycorrhiza (VAM) is an example of endomycorrhiza in which fungal hyphae penetrate the cortical cells of grasses to form vesicles.

Biofertilizers are organisms which bring about nutrient enrichment of the soil. Azotobacter is a free living, aerobic, nitrogen fixing bacteria. Anabena is a nitrogen fixing cyanobacteria that occurs in both free living and symbiote associations with Azolla, Cycas roots etc. Rhizobium lives symbiotically in root nodules of legumes and non-legumes. Vesicular-arbuscular mycorrhiza (VAM) is an example of endomycorrhiza in which fungal hyphae penetrate the cortical cells of grasses to form vesicles.

Saccharomyces convert starch or sugars to pyruvic acid through EM P pathway. Then this pyruvic acid is converted to acetaldehyde and finally to ethyl alcohol in the absence of oxygen. This entire process is called fermentation. C6H12O6-->2CH2COCOOH-->2C2H3OH+2CO2

Azolla is a fern in the leaf cavities of which the blue green algae Anahaena is found. This Azolla-Anabena symbiotic system is the main biofertilizer which increases yield upto 50% Anabaena fixes nitrogen which is excreted in the leaf cavities and is made available to the fern. When the fern plants die and decay they release nitrogen for utilization of the rice plants.

Azolla plays a very important role in rice production. Azolla and its nitrogen-fixing partner, Anabaena, have been used as green manure to fertilize rice paddies and increase production. With the help of Azolla, rice can be grown year after year, several crops a year, with little or no decline in productivity; hence no rotation of crops is necessary.

Azolla plays a very important role in rice production. Azolla and its nitrogen-fixing partner, Anabaena, have been used as green manure to fertilize rice paddies and increase production. With the help of Azolla, rice can be grown year after year, several crops a year, with little or no decline in productivity; hence no rotation of crops is necessary.

Saccharomyces converts starch or sugars to pyruvic acid through EM P pathway. Then this pyruvic acid is converted to acetaldehyde and finally to ethyl alcohol in the absence of oxygen. This entire process is called fermentation.C6H12O6-->2CH2COCOOH-->2C2H3OH+2CO2 This released carbon dioxide from yeast makes the dough to rise and gives spongy nature to bread.

Methanogens are a type of archaebacteria that occurs in marshes, swamps and rumen of cattles. They are obligate anaerobes that can catabolize acetate and H2 to gaseous products and are used in the final stage 446 called methanogenesis of biogas production in gobar gas plant. Nitrilying bacteria oxidise NH3, into NO2 and later to NO3. Ammonifying bacteria convert proteins into NH3 Denitrifying bacteria reduce NO3, into NH3,.

Lignin is a complex polymer of phenylpropane units, which are cross-linked to each other with a variety of different chemical bonds. This complexity has thus far proven as resistant to microbial degradation. Cellulose is a long chain of glucose molecules, linked to one another primarily with glycosidic bonds. The simplicity of the cellulosic structure, using repeated identical bonds, means that only a small number of enzymes are required to degrade this material. Hemicelluloses are branched polymers of xylose, arabinose, galactose, mannose, and glucose. Hemicelluloses bind bundles of cellulose fibrils to form microfibrils, which enhance the stability of the cell wall but these can be degraded by increasing the number of enzymes.

The term ?antibiotics? was first time used by S.A. Waksman in 1945. Antibiotics are the substances which are produced by micro-organisms such as fungi or bacteria. These substances are harmful to the growth of other micro-organisms. e.g., Penicillin, streptomycin, chloramphenicol etc.

Biogas or gobar gas is a methane rich fuel gas produced by anaerobic breakdown or digestion of biomass with the help of methanogenic bacteria. It is made up of methane (50 - 70%), carbon dioxide (30 - 40%) with traces of nitrogen, hydrogen sulphide and hydrogen.

The AB blood group is often referred to as the ""universal recipient"" because individuals with this blood type can receive blood from donors of any ABO blood type without experiencing a major transfusion reaction, as there are no antibodies in their plasma to react with the A or B antigens on the donor's red blood cells. So, the correct option is (B): AB

Answer (b) biological control of soil-borne plant pathogens

Paecilomyces Iilacinus proved effective for biological control of nematodal diseases in plant.

Xanthomonas campestris is not used as a biopesticide. Bacillus thuringiensis is used as a microbial biocontrol agent. Trichoderma harzianum is a free-living fungi, common in soil and root ecosystems. It is an effective biocontrol agent of several plant pathogens. Viruses of the family Baculoviruses are pathogens that attack insects and other arthropods. The majority of baculoviruses used as biological control agents belong to genus Nucleopolyhedrovirus

The natural method of pest and pathogen control involving use of viruses, bacteria and other insects (which are their natural predators and pests) is called biocontrol or biological control. For example, free living fungus Trichoderma exerts biocontrol over several plant pathogens for the control of plant diseases. Baculoviruses (mostly of genus Nucleo-polyhedrovirus) are also used as biocontrol agents but they are used for the control of insects and arthropods. Bacillus thuringiensis is a soil bacterium which is used as biopesticide. Glomus ; species are the most common fungal partners of mycorrhiza residing in the roots of higher plants,

In activated sludge system (secondary sewage treatment), the primary effluent is taken to aeration tank. A large number of aerobic heterotrophic microbes grow in aeration tank. They form floes, which digest a lot of organic matter. As the BOD of waste water is reduced sufficiently, it is passed into setting tank where bacterial floes are allowed to undergo sedimentation. The sediment of the settling tank is called activated sludge which is a rich source of aerobic bacteria. It is further processed in anaerobic sludge digester. Biogas commonly called gobar gas is produced by anaerobic breakdown of biomass with the help of methanogenic bacteria. Biogas is made up of methane (50-70%), CO (30-40%) with traces of nitrogen, hydrogen sulphide and hydrogen. Methanobacterium is an anaerobic methanogenic bacteria which is found in rumen of cattle and helpful in the breakdown of cellulose.

Organic farming is a method of farming system which primarily aimed to keep the soil alive and in good health by use of organic wastes and other biological material alongwith beneficial microbes (biofertilizers) to release nutrients to crops for increased sustainable production in an ecofriendly, pollution free environment. Basic components of organic farming are green manures, farm yard manure, vermicompost, crop rotation, biopesticides and biofertilizers. Glomus being a mycorrhizal component, earthworm being a vermicompost and Oscillatoria being a nitrogen fixing blue green algae can be used in organic farming. Snail cannot be a component of organic farming.

When sewage mixes with water body, micro- organisms present in it biodegrade organic matter of sewage using oxygen. This results into a sharp decline in dissolved oxygen which may cause mortality of aquatic creatures. Gradually, however, dissolved oxygen increases in concentration with the completion of biodegradation of sewage matter.

Biofertilizers are organisms that enrich the nutrient quality of the soil. The main sources of biofertilizers are bacteria, fungi and cyanobacteria. Rhizobium bacteria is found in the nodules on the roots of leguminous plants by symbiotic association. These bacteria fix atmospheric nitrogen into organic forms, which is used by the plants as nutrient. Fungi are also known to form symbiotic associations with plants called mycorrhiza. Cyanobacteria are autotrophic microbes widely distributed in an aquatic and terrestrial environments. Many of which can fix atmospheric nitrogen, e.g., Anabaena, Nos toe, Oscillator ia etc. But Agrobacterium tumefaciens is a pathogen of several dicot plants. It causes gall tumor in the plants.

Rhizobium is used as a biofertilizer for raising crop. Rhizobium japonicum forms symbiotic association in the roots of the leguminous plant, soyabean.

Fed-batch culture is an operational technique where one or more nutrients (substrates) are fed (supplied) to the bioreactor during cultivation and in which the product(s) remain in the bioreactor until the end of the run. Continuous addition of sugars in 'fed-batch' fermentation is done to purify the enzymes.

Ethanol is commercially produced through a particular species of yeast Saccharomyces (Saccharomyces cerevisiae).

Sewage water can be purified by passing it through sewage treatment plants with the action of heterotrophic microorganisms. There are three stages of this treatment - primary, secondary and tertiary. Primary treatment removes floating and suspended solids from sewage through two processes of filtration and sedimentation. First floating matter is removed through sequential filtration. The filtrate is kept in large open settling tanks where grit settles down. The sediment is called primary sludge while the supernatant is called effluent. The primary sludge traps a lot of microbes and debris. In secondary treatment, the primary effluent is taken to aeration tanks. A large number of aerobic heterotrophic microbes grow in the aeration tank. They form floes. Floes are masses of bacteria held together by slime and fungal filaments to form mesh like structures. The microbes digest a lot of organic matter, converting it into microbial biomass and releasing aflot of minerals. As the BOD of the waste matter is reduced to 10-15% of raw sewage, it is passed into settling tank. Thus secondary treatment is more or less biological. The sediment of settling tank is called activated sludge. The remaining is passed into a large tank called anaerobic sludge digester. It is designed for continuous operation. The aerobic microbes present in the sludge get killed. Anaerobic microbes digest the organic mass as well as aerobic microbes of the sludge. They are of two types, nonmethanogenic and methanogenic. Methanogenic bacteria produce a mixture of gases containing methane, H2S and CO2

Statins are produced by the yeast Monascus purpureus which have been commercialized as blood- cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.

Biogas is made up of methane (50-70%), carbon dioxide (30-40%) and hydrogen sulphide. However traces of nitrogen, hydrogen and oxygen arc also found.

The correct option (A): Methane, hydrogen sulphide and CO₂.

The correct option is (C): Primary treatment.

The correct option is (D): Saccharomyces cerevisiae : Ethanol.

The correct answer is B:Primary treatment
In the primary stage of sewage treatment, suspended particles are eliminated through a process known as physical treatment. This process involves actions like shredding, churning, screening, and sedimentation. Additionally, sequential filtration is employed to eliminate floating materials and large suspended solids.

Rhodospirillum is anaerobic, free living nitrogen fixer. Mycorrhiza is a symbiotic relationship between fungi and roots of higher plants.

The correct option is (B) :a-(ii) b- (iv) c-(iii) d-(v)

The correct option is (B) :Trichoderma, Baculovirus, Bacillus thuringiensis

Fungs Trichoderma, Baculoviruses (NPV) and Bacillus thuringiensis are used as biocontrol agents.
Rhizobium, Nostoc, Azospirillum and Oscillatoria are used as biofertilisers, whereas TMV is a pathogen and aphids are pests that harm crop plants.

Statin is obtained from a yeast (Fungi) called Monascus purpureus
It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.