Lesson 11 of 11 · 13 min
Chapter review
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Must-know facts
20 facts
- 01Microbes survive in geysers at up to 100°C, under thick snow, deep in soil and in acidic places; prions are protein infectious agents.
- 02Curd: Lactobacillus (LAB); acids coagulate milk proteins; vitamin B12 rises.
- 03Idli and dosa dough: fermented by bacteria, puffed by CO₂. Bread: baker's yeast, Saccharomyces cerevisiae.
- 04Toddy: fermented palm sap.
- 05Swiss cheese holes: CO₂ from Propionibacterium sharmanii. Roquefort cheese: ripened by a fungus.
- 06Wine and beer: no distillation. Whisky, brandy, rum: distilled.
- 07Penicillin from Penicillium notatum; Fleming noticed it on a Staphylococci plate; Chain and Florey proved its worth; Nobel Prize 1945.
- 08Citric acid: Aspergillus niger. Acetic acid: Acetobacter aceti. Butyric acid: Clostridium butylicum. Lactic acid: Lactobacillus.
- 09Lipases in detergents; pectinases and proteases clarify fruit juice.
- 10Streptokinase (Streptococcus) is a clot buster for heart-attack patients.
- 11Cyclosporin A: Trichoderma polysporum, immunosuppressant. Statins: Monascus purpureus, lower cholesterol by competitive inhibition.
- 12Primary treatment: physical, filtration and sedimentation; gives primary sludge and effluent.
- 13Secondary treatment: aeration tanks, flocs of bacteria and fungal filaments, BOD falls; activated sludge settles, part returned as inoculum.
- 14BOD: oxygen used if bacteria oxidised all organic matter in one litre of water; higher BOD means more polluting.
- 15Anaerobic sludge digesters give biogas: methane, H₂S, CO₂.
- 16Methanogens (Methanobacterium) live in sludge and the cattle rumen; biogas plant tank 10-15 feet deep; IARI and KVIC.
- 17Ladybird eats aphids; dragonfly eats mosquitoes; Bt kills butterfly caterpillars; Trichoderma controls plant pathogens.
- 18Baculoviruses (Nucleopolyhedrovirus) are species-specific, narrow-spectrum insecticides suited to IPM.
- 19Rhizobium: symbiotic in legume nodules. Azospirillum, Azotobacter: free-living nitrogen fixers.
- 20Glomus forms mycorrhiza and supplies phosphorus. Anabaena, Nostoc, Oscillatoria fix nitrogen in paddy fields.
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Key terms
19 terms
- Lactic acid bacteria (LAB)
- Bacteria such as Lactobacillus that turn milk into curd by making acids.
- Inoculum (starter)
- A small amount of a culture added to start fermentation, like curd added to milk.
- Fermentor
- A very large vessel for growing microbes on an industrial scale.
- Distillation
- The step that separates whisky, brandy and rum from undistilled wine and beer.
- Antibiotic
- A chemical made by a microbe that kills or slows the growth of other, disease-causing microbes.
- Streptokinase
- A clot-dissolving enzyme from Streptococcus, used for heart-attack patients.
- Cyclosporin A
- An immunosuppressant for transplant patients, made by Trichoderma polysporum.
- Statins
- Cholesterol-lowering agents from the yeast Monascus purpureus.
- Sewage
- Municipal waste water, rich in organic matter and microbes.
- Primary sludge
- The solids that settle out during primary treatment.
- Flocs
- Mesh-like masses of bacteria and fungal filaments that grow in aeration tanks.
- BOD
- Biochemical oxygen demand: the oxygen bacteria would use to oxidise all the organic matter in one litre of water.
- Activated sludge
- The settled flocs after aeration; part returns to the aeration tank as inoculum.
- Methanogens
- Anaerobic bacteria such as Methanobacterium that make methane from cellulosic material.
- Biocontrol
- Controlling plant pests and diseases by biological methods instead of chemicals.
- Bt
- Bacillus thuringiensis, a bacterium whose toxin kills caterpillars.
- Baculoviruses
- Insect-attacking viruses, mainly Nucleopolyhedrovirus, used as narrow-spectrum insecticides.
- Biofertiliser
- An organism that enriches the nutrient quality of soil.
- Mycorrhiza
- A symbiotic association of a fungus, such as Glomus, with plant roots.