Microbes in human welfare

N.SENTHILKUMAR

PG ASST IN ZOOLOGY

GOVT BOYS HIGHER SEC. SCHOOL

THALAIVASAL , ATTUR( TK), SALEM (DT)

Microbes in household products

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Curd

Lactobacillus.sp

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• The lactic acid bacteria grows in milk and convert it into curd, there by digesting the milk protein casein.

�Streptococcus thermophilus�Yogurt

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• Yogurt is produced by bacterial fermentation of milk, and lactic acid is produced as a by product.

��Lactococcus �Cheese �

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• Cheese is formed by coagulation of the milk protein, casein.
• Milk is usually acidified and the enzyme rennet is added to cause coagulation.

Paneer �(cottage cheese)

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• It is made by curdling milk with lemon juice, vinegar and other edible acids

Dough (Idlis and dosa)

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• The dough used in the preparation of idlis and dosas are fermented by the bacteria Leuconostoc mesenteroides

Dough (Bread making)

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• Dough used in bread making is fermented by Saccharomyces cerevisiae (Baker’s Yeast)

�Microbes in industrial products

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• Products like beverages, antibiotics, organic acids, amino acids, vitamins, biofuels, single cell protein, enzymes, steroids, vaccines, pharmaceutical drugs, etc., are produced in industries.

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Bioreactor

�Antibiotic production

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• Antibiotics are chemical substances produced by microorganisms which can kill or retard the growth of other disease causing microbes even in low concentration.

Penicillin

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• Penicillin is produced by the fungi Penicillium notatum and Penicillium chrysogenum. It is bactericidal in action and inhibits the synthesis of the bacterial cell wall.
• Fleming, Chain and Florey were awarded the Nobel prize in 1945 for the discovery of penicillin

�Tetracycline

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• Tetracycline is a broad spectrum bacteriostatic antibiotic that inhibits microbial protein synthesis.

�Streptomycin

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• Streptomycin is a broad spectrum antibiotic isolated from the actinomycetes, Streptomyces griseus.
• It is bactericidal against both gram positive and gram negative bacteria, especially against Mycobacterium tuberculosis.

�Antibiotic resistance

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• Antibiotic resistance occurs when bacteria develop the ability to defeat the drug designed to kill or inhibit their growth.
• Antibiotic resistance is accelerated by the misuse and over use of antibiotics
• Superbug- Strains of bacteria that are resistant to the majority of antibiotics

�Fermented beverages

• Microbes especially yeast is being used from time immemorial for the production of beverages like wine, beer, whisky, brandy and rum.
• Zymology is an applied science which deals with the biochemical process of fermentation.

�Pathaneer

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• Pathaneer is obtained from fermenting sap of palms and coconut trees.
• A common source is tapping of unopened spadices of coconut.
• It is a refreshing drink, which on boiling produces jaggery or palm sugar.

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�Ethanol production process

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�Chemicals, enzymes and other bioactive molecules

Chemicals

• Microbes are not only used for commercial and industrial production of alcohol, but also used for production of organic acids
• Aspergillus niger for citric acid, Acetobacter aceti for acetic acid, Rhizopus oryzae for fumaric acid, Clostridium butyricum for butyric acid and Lactobacillus for lactic acid.

Enzymes

• Lipases are used in detergent formulations and are used for removing oily stains
• Bottled juices are clarified by the use of pectinase, protease and cellulase.
• Rennet can also be used to separate milk into solid curds for cheese making
• Streptococcus and genetically engineered Streptococci are used as “clot buster” for removing clots from the blood vessels.

�Bioactive molecules

• Cyclosporin A, an immunosuppressant used in organ transplantation is produced from the fungus Trichoderma polysporum.It is also used for its anti-inflammatory, anti-fungal and anti-parasitic properties.
• Statins produced by the yeast Monascus purpureus have been used to lower blood cholesterol levels.

�Wastewater treatment

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• To reduce organic and inorganic components in wastewater to a level that it no longer supports microbial growth and to eliminate other potentially toxic materials.

�Primary treatment

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• Primary treatment involves the physical removal of solid and particulate organic and inorganic materials from the sewage through filtration and sedimentation.

�Secondary treatment or biological treatment

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• The primary effluent is passed into large aeration tanks where it is constantly agitated mechanically and air is pumped into it.
• This allows vigorous growth of useful aerobic microbes into floc
• This significantly reduces the BOD (Biochemical oxygen demand or Biological oxygen demand

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�Tertiary treatment

• Final process that improves the quality of the waste water before it is reused, recycled or released into natural water bodies.
• This treatment removes the remaining inorganic compounds and substances, such as nitrogen and phosphorus.
• UV is an ideal disinfectant for wastewater since it does not alter the water quality and also inactivates chlorine-resistant microorganisms .

�Chlorination system

�National river conservation plan (NRCP)

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• To capture the raw sewage flowing into the river through open drains and divert them for treatment.
• Setting up sewage treatment plants for treating the diverted sewage.
• Construction of low cost sanitation toilets to prevent open defecation on river banks.

Microbial fuel cell

Microbial fuel cell

• A microbial fuel cell is a bio-electrochemical system that drives an electric current by using bacteria found in nature.
• It work by allowing bacteria to oxidize and reduce organic molecules
• Bacterial respiration is basically one big redox reaction in which electrons are being moved around.

• A MFC consists of an anode and a cathode separated by a proton exchange membrane.
• Microbes at the anode oxidize the organic fuel generating protons which pass through the membrane to the cathode and the electrons pass through the anode to the external circuit to generate current.

Microbial fuel cell

�Microbes in the production of biogas

• Biogas is a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen.
• Biogas is produced under anaerobic condition, when the organic materials are converted through microbiological reactions into gas and organic fertilizer.
• Biogas primarily consists of methane (63 percent), along with CO2 and hydrogen.

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• Methane producing bacteria are called methanogens and one such common bacterium is Methanobacterium
• The excreta of cattle called dung is commonly called “Gobar”.
• Gobar gas is generated by the anaerobic decomposition of cattle dung.
• The technology of biogas production was developed in India mainly due to the efforts of Indian Agricultural Research Institute (IARI) and Khadi and Village Industries Commission (KVIC).

Gobar gas unit

�Microbes as bio control agents

• Biocontrol is a method of controlling pest by use of microbes such as fungi, bacteria, viruses or by naturally occurring substances derived from plants and animals.
• The use of a microbes or other biological agents to control a specific pest is called a biopesticide.
• Trichoderma species are free living fungi that are very common in the root ecosystem.They are effective biocontrol agents for several plant pathogens.

�Lady bird beetle and dragonflies

Lady bird beetle control

aphids

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Dragonflies controls mosquito larvae

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�Bacillus thuringiensis

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• Bacillus thuringiensis is a soil dwelling bacterium which is commonly used as a biopesticide and contains a toxin called cry toxin .

�Actions of cry toxin

�Biofertilisers

• Biofertilisers are formulation of living microorganisms that enrich the nutrient quality of the soil
• The main sources of biofertilisers are bacteria, fungi and cyanobacteria.

�Rhizobium�(symbiotic nitrogen fixing bacteria)

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• Rhizobium infects the root nodules of leguminous plants and fixes atmospheric nitrogen into organic forms

� Azospirillum Azotobacter �

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• Azospirillum and Azotobacter are free living bacteria that fix atmospheric nitrogen and enrich the nitrogen content of soil.

�Cyanobacteria

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• Cyanobacteria (or) blue green algae (BGA) are prokaryotic free-living organisms which can fix nitrogen.

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• Oscillatoria, Nostoc, Anabaena, Tolypothrix are well known nitrogen fixing cyanobacteria.

�Bioremediation

• The use of naturally occurring or genetically engineered microorganisms to reduce or degrade pollutants is called bioremediation.
• Types

In situ bioremediation (treatment of contaminated soil or water in the site)

Ex situ bioremediation (treatment of contaminated soil or water in the site)

�Pseudomonas putida

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• Pseudomonas putida is multi-plasmid hydrocarbon-degrading bacterium which can digest the hydrocarbons in the oil spills

� Process of bioremediation

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Ideonella sakaiensis

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• Ideonella sakaiensis is currently tried for recycling of PET plastics.
• These bacteria use PETase and MHETase enzymes to breakdown PET plastic into terephthalic acid and ethylene glycol.

N.SENTHILKUMAR

PG ASST IN ZOOLOGY

GOVT BOYS HIGHER SEC SCHOOL

THALAIVASAL , ATTUR( TK), SALEM (DT)