Introduction to Microbiology
Short Questions
1. How does applied microbiology differ from industrial microbiology?
Answer : Applied microbiology studies microbial enzymes and genetics, while industrial microbiology focuses on their commercial applications.
2. What role does pasteurization play in yoghurt production?
Answer : It eliminates unwanted microbes to ensure safe fermentation.
3. Why is lactic acid critical in milk product formation?
Answer : It coagulates milk proteins, enhancing texture and flavor.
4. How does Streptococcus thermophilus contribute to yoghurt’s texture?
Answer : It produces lactic acid, causing protein gelation for density.
5. What distinguishes cultured butter from sweet cream butter?
Answer : Cultured butter uses microbial fermentation for flavor, unlike sweet cream butter.
6. Why is fungal protease preferred over rennet in vegetarian cheese?
Answer : It avoids animal-derived enzymes, ensuring vegetarian compatibility.
7. How does acetaldehyde enhance yoghurt’s appeal?
Answer : It imparts the characteristic taste of yoghurt.
8. What makes Saccharomyces cerevisiae essential in vinegar production?
Answer : It ferments sugars into ethanol, a precursor to acetic acid.
9. How do probiotics counteract the effects of antibiotics?
Answer : They restore active gut microbes disrupted by antibiotics.
10. Why is compressed yeast preferred in commercial baking?
Answer : It ensures consistent fermentation for large-scale bread production.
11. What property of xanthan gum makes it valuable in food industries?
Answer : Its high density and solubility in hot and cold water.
12. How do hydrocarbonoclastic bacteria remediate oil spills?
Answer : They degrade hydrocarbons into CO2 and water.
13. Why are microbial enzymes eco-friendly in chemical industries?
Answer : They reduce energy use and minimize harmful by-products.
14. What role do phenol-oxidizing bacteria play in sewage treatment?
Answer : They break down toxic xenobiotic chemicals in sewage.
15. How does Geobacter prevent groundwater contamination?
Answer : It converts soluble uranium salts into insoluble forms.
16. Why is methane considered a key biofuel from microbial processes?
Answer : It’s produced via anaerobic decomposition of organic waste.
17. What makes bioinsecticides specific to pests?
Answer : Bacterial and fungal toxins target pests without harming plants.
18. How do microbes enhance compost quality in landfills?
Answer : They decompose organic waste, producing nutrient-rich compost.
19. Why is segregation of wet and dry waste crucial for microbial decomposition?
Answer : It ensures only degradable waste is processed by microbes.
20. How do Acidobacillus ferroxidens utilize sulfuric acid in pollution control?
Answer : They use it as an energy source to reduce soil pollution from acid rain.
Long Questions
1. What are the main features of industrial microbiology?
Answer : It involves large-scale production using microbial fermentation for products like bread, cheese, and medicines. Microbes are also used for garbage management and pollution control. It supports economic, social, and environmental benefits through microbial processes.
2. Explain the process of yoghurt production.
Answer : Milk is pasteurized, cooled, and inoculated with Streptococcus thermophilus and Lactobacillus delbrueckii. Lactic acid from Streptococcus gels milk proteins, giving dense texture. Lactobacillus produces acetaldehyde, imparting characteristic taste.
3. How is cheese produced industrially?
Answer : Milk is tested, mixed with bacteria like Lactobacillus lactis, and fermented. Fungal protease or rennet coagulates milk, and whey is removed. The curd is processed, salted, and ripened to form cheese.
4. What is the role of probiotics in human health?
Answer : Probiotics like Lactobacillus maintain intestinal microbial balance, aiding digestion. They reduce harmful microbes and counter antibiotic-induced microbial inactivity. They are used to treat diarrhoea and support poultry health.
5. How is vinegar produced using microbes?
Answer : Ethanol is fermented from carbon compounds using Saccharomyces cerevisiae. Acetobacter and Gluconobacter convert ethanol to acetic acid. The acid is purified, bleached, and pasteurized to produce vinegar.
6. Describe the role of microbial enzymes in industries.
Answer : Microbial enzymes like oxidoreductases work at low temperatures, saving energy. They minimize by-products, reducing purification costs. They are eco-friendly and reusable in industries like textiles and cheese production.
7. How do microbes help in sewage management?
Answer : Microbes decompose carbon compounds in sewage, releasing methane and CO2. Phenol-oxidizing bacteria break down toxic chemicals. The resulting sludge is used as fertilizer, and water is made environmentally safe.
8. Explain the role of microbes in cleaning oil spills.
Answer : Hydrocarbonoclastic bacteria like Pseudomonas spp. and Alcanovorax borkumensis degrade oil hydrocarbons. They convert hydrocarbons into CO2 and water. This process cleans oil spills in oceans effectively.
9. What is the importance of microbial inoculants in farming?
Answer : Microbial inoculants like Azotobacter supply nutrients to plants, enhancing growth. They reduce reliance on chemical fertilizers, preventing soil pollution. They improve the quality of vegetarian food in organic farming.
10. Why are biofuels considered important, and how are they produced?
Answer : Biofuels like methane and ethanol are renewable and eco-friendly. Methane is produced by microbial decomposition of waste, and ethanol by yeast fermentation of molasses. They reduce reliance on fossil fuels, supporting sustainability.
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