Here below some basic MCQ’s of Microbes in human walefare with answer which is well explained. Let’s check one by one.
- Which of the following microorganisms is used in the production of ethanol?
A. Aspergillus niger
B. Saccharomyces cerevisiae
C. Penicillium chrysogenum
D. Rhizopus stolonifer
Answer: B. Saccharomyces cerevisiae
Explanation:
Saccharomyces cerevisiae (commonly known as brewer’s yeast) is used in the fermentation of sugars to produce ethanol. This process is vital in brewing and baking industries.
- Which of the following is not used as a biofertilizer?
A. Rhizobium
B. Azotobacter
C. Mycorrhiza
D. Lactobacillus
Answer: D. Lactobacillus
Explanation:
Lactobacillus is used in the production of dairy products like curd and is not involved in improving soil fertility. On the other hand, Rhizobium, Azotobacter, and Mycorrhiza are used to enhance plant growth by fixing nitrogen or increasing nutrient uptake.
- Which microorganism is used for the production of the antibiotic penicillin?
A. Streptomyces griseus
B. Penicillium notatum
C. Clostridium butylicum
D. Lactobacillus bulgaricus
Answer: B. Penicillium notatum
Explanation:
Penicillium notatum was the original fungus from which penicillin was discovered by Alexander Fleming. It is widely used to produce this antibiotic, which is effective against a broad spectrum of bacteria.
- What is the primary role of cyanobacteria in the environment?
A. Methane production
B. Photosynthesis and nitrogen fixation
C. Lactic acid production
D. Alcohol fermentation
Answer: B. Photosynthesis and nitrogen fixation
Explanation:
Cyanobacteria are important for their ability to perform oxygenic photosynthesis and fix atmospheric nitrogen, making them essential for both carbon and nitrogen cycles in the environment.
- Which of the following microorganisms is used in the production of Swiss cheese?
A. Penicillium roqueforti
B. Streptococcus thermophilus
C. Propionibacterium shermanii
D. Saccharomyces cerevisiae
Answer: C. Propionibacterium shermanii
Explanation:
Propionibacterium shermanii is involved in the production of Swiss cheese and is responsible for the characteristic holes in the cheese, caused by the release of carbon dioxide during fermentation.
- In the production of curd, which bacterium is commonly used?
A. Lactobacillus acidophilus
B. Escherichia coli
C. Clostridium tetani
D. Saccharomyces cerevisiae
Answer: A. Lactobacillus acidophilus
Explanation:
Lactobacillus acidophilus is commonly used in the fermentation process to convert lactose (milk sugar) into lactic acid, which results in the thickening of milk to form curd.
- Which microorganism is used in the production of cyclosporin A, an immunosuppressive drug?
A. Trichoderma polysporum
B. Aspergillus niger
C. Rhizobium
D. Methanobacterium
Answer: A. Trichoderma polysporum
Explanation:
Trichoderma polysporum is a fungus used in the production of cyclosporin A, which is widely used as an immunosuppressive drug, especially during organ transplant procedures.
- Which microorganism helps in the biogas production process?
A. Rhizobium
B. Methanobacterium
C. Penicillium
D. Azotobacter
Answer: B. Methanobacterium
Explanation:
Methanobacterium is a type of archaea involved in the production of methane (biogas) by breaking down organic matter anaerobically in biogas plants.
- Which of the following microbes is involved in the production of citric acid?
A. Penicillium chrysogenum
B. Aspergillus niger
C. Saccharomyces cerevisiae
D. Rhizopus stolonifer
Answer: B. Aspergillus niger
Explanation:
Aspergillus niger is used industrially for the production of citric acid, which is used as a preservative and flavoring agent in the food and beverage industries.
- The role of Rhizobium in agriculture is:
A. Decomposition of organic matter
B. Nitrogen fixation in leguminous plants
C. Production of antibiotics
D. Fermentation of sugars
Answer: B. Nitrogen fixation in leguminous plants
Explanation:
Rhizobium is a nitrogen-fixing bacterium that forms a symbiotic relationship with leguminous plants, converting atmospheric nitrogen into a form that the plants can utilize for growth.
- Which of the following microorganisms is used for producing acetic acid (vinegar)?
A. Acetobacter aceti
B. Saccharomyces cerevisiae
C. Penicillium notatum
D. Lactobacillus bulgaricus
Answer: A. Acetobacter aceti
Explanation:
Acetobacter aceti is used in the fermentation process that converts ethanol into acetic acid, which is the key component of vinegar.
- Which of the following is responsible for the formation of biofertilizer in rice fields?
A. Azospirillum
B. Anabaena
C. Rhizobium
D. Pseudomonas
Answer: B. Anabaena
Explanation:
Anabaena is a nitrogen-fixing cyanobacterium that forms a symbiotic association with aquatic plants like Azolla, enhancing soil fertility in rice fields.
- The organism used for the large-scale production of ethanol from molasses is:
A. Clostridium butylicum
B. Saccharomyces cerevisiae
C. Lactobacillus acidophilus
D. Streptococcus lactis
Answer: B. Saccharomyces cerevisiae
Explanation:
Molasses, a by-product of sugar production, is fermented by Saccharomyces cerevisiae (yeast) to produce ethanol on an industrial scale.
- Rhizobium is associated with which part of leguminous plants?
A. Roots
B. Stem
C. Leaves
D. Flowers
Answer: A. Roots
Explanation:
Rhizobium forms nodules on the roots of leguminous plants, where they fix atmospheric nitrogen into ammonia, enriching soil nitrogen levels.
- The microorganism used in the production of butyric acid is:
A. Clostridium butylicum
B. Aspergillus niger
C. Saccharomyces cerevisiae
D. Lactobacillus acidophilus
Answer: A. Clostridium butylicum
Explanation:
Clostridium butylicum is involved in the fermentation process that produces butyric acid, a substance used in various industries like plastics and pharmaceuticals.
- In sewage treatment, which of the following is the main process involved in the secondary treatment?
A. Chemical treatment
B. Biological treatment
C. Mechanical filtration
D. Aeration
Answer: B. Biological treatment
Explanation:
The secondary treatment of sewage involves microbial decomposition of organic waste. This is primarily done by aerobic bacteria in the activated sludge process.
- The microbe used for the production of biogas from cattle dung is:
A. Methanobacterium
B. Azotobacter
C. Lactobacillus
D. Saccharomyces cerevisiae
Answer: A. Methanobacterium
Explanation:
Methanobacterium, an anaerobic microorganism, is used in biogas plants to break down organic matter such as cattle dung to produce methane, the primary component of biogas.
- Which microorganism helps in the ripening of cheese?
A. Lactobacillus acidophilus
B. Penicillium roqueforti
C. Streptococcus thermophilus
D. Saccharomyces cerevisiae
Answer: B. Penicillium roqueforti
Explanation:
Penicillium roqueforti is used in the ripening of blue cheeses, such as Roquefort, where it forms characteristic blue veins that add flavor and texture.
- Which of the following is used in the biological control of plant diseases?
A. Penicillium notatum
B. Trichoderma harzianum
C. Azotobacter
D. Lactobacillus acidophilus
Answer: B. Trichoderma harzianum
Explanation:
Trichoderma harzianum is a fungus used in biological control to protect plants from various fungal pathogens by producing enzymes that break down the cell walls of harmful fungi.
- The role of Lactobacillus in milk fermentation is:
A. To produce carbon dioxide
B. To convert lactose into lactic acid
C. To produce alcohol
D. To convert ethanol into acetic acid
Answer: B. To convert lactose into lactic acid
Explanation:
Lactobacillus bacteria convert lactose (milk sugar) into lactic acid during the fermentation process, leading to the thickening of milk and the production of curd.
- Which of the following is a free-living nitrogen-fixing bacterium?
A. Rhizobium
B. Azotobacter
C. Penicillium
D. Saccharomyces
Answer: B. Azotobacter
Explanation:
Azotobacter is a free-living nitrogen-fixing bacterium that is found in soil and helps to increase the nitrogen content without forming symbiotic relationships with plants.
- The organism that produces the antibiotic streptomycin is:
A. Streptomyces griseus
B. Penicillium notatum
C. Aspergillus niger
D. Rhizopus stolonifer
Answer: A. Streptomyces griseus
Explanation:
Streptomyces griseus is a bacterium that produces streptomycin, an antibiotic used to treat bacterial infections such as tuberculosis.
- Which microorganism is commonly used in sewage treatment plants?
A. Rhizobium
B. Azospirillum
C. Methanobacterium
D. Activated sludge bacteria
Answer: D. Activated sludge bacteria
Explanation:
In sewage treatment plants, aerobic bacteria in the activated sludge process break down organic matter in the wastewater, leading to its purification.
- Monascus purpureus is used for the production of:
A. Ethanol
B. Statins
C. Antibiotics
D. Biogas
Answer: B. Statins
Explanation:
Monascus purpureus, a red yeast, produces statins, which are cholesterol-lowering drugs used in the prevention of cardiovascular diseases.
- The term “flocs” in sewage treatment refers to:
A. Solid waste in sewage
B. Bacteria and fungi associated with sewage sludge
C. Viruses in sewage
D. Chemical coagulants
Answer: B. Bacteria and fungi associated with sewage sludge
Explanation:
“Flocs” are clusters of bacteria and fungi in activated sludge that help break down organic pollutants during the secondary treatment of sewage.
- The production of alcoholic beverages like beer and wine is primarily carried out by:
A. Streptococcus lactis
B. Saccharomyces cerevisiae
C. Clostridium butylicum
D. Azotobacter
Answer: B. Saccharomyces cerevisiae
Explanation:
Saccharomyces cerevisiae (brewer’s yeast) is used in the fermentation process to convert sugars into alcohol, which is essential for the production of beer and wine.
- Which of the following microbes is used in the production of bioinsecticides?
A. Bacillus thuringiensis
B. Penicillium notatum
C. Streptococcus thermophilus
D. Rhizobium
Answer: A. Bacillus thuringiensis
Explanation:
Bacillus thuringiensis produces proteins that are toxic to insect larvae, making it an effective bioinsecticide used in organic farming.
- The first antibiotic discovered by Alexander Fleming was:
A. Streptomycin
B. Penicillin
C. Tetracycline
D. Erythromycin
Answer: B. Penicillin
Explanation:
Penicillin was the first antibiotic discovered by Alexander Fleming in 1928. It was derived from the fungus Penicillium notatum and has been used to treat bacterial infections.
- The “blue-green algae” that are commonly used as biofertilizers in paddy fields are:
A. Anabaena and Nostoc
B. Penicillium and Rhizopus
C. Aspergillus and Rhizopus
D. Streptococcus and Lactobacillus
Answer: A. Anabaena and Nostoc
Explanation:
Cyanobacteria like Anabaena and Nostoc fix atmospheric nitrogen in paddy fields, acting as biofertilizers that help increase soil fertility.
- In the context of industrial biotechnology, the production of citric acid involves which microorganism?
A. Rhizopus stolonifer
B. Aspergillus niger
C. Saccharomyces cerevisiae
D. Penicillium chrysogenum
Answer: B. Aspergillus niger
Explanation:
Aspergillus niger is widely used in the industrial production of citric acid, which is an important additive in the food and beverage industry.
- The role of bacteria in the nitrogen cycle is:
A. Production of oxygen
B. Fixation of nitrogen
C. Decomposition of dead organic matter
D. Photosynthesis
Answer: B. Fixation of nitrogen
Explanation:
Nitrogen-fixing bacteria, such as Rhizobium and Azotobacter, convert atmospheric nitrogen into forms usable by plants, an essential step in the nitrogen cycle.
- Which of the following microorganisms is used in the production of ethanol from starch?
A. Lactobacillus
B. Streptococcus
C. Saccharomyces cerevisiae
D. Clostridium
Answer: C. Saccharomyces cerevisiae
Explanation:
Saccharomyces cerevisiae (yeast) is employed in fermenting starch-derived sugars to produce ethanol, particularly in biofuel and beverage industries.
- Which of the following biofertilizers is commonly used for improving soil fertility in legume crops?
A. Rhizobium
B. Penicillium
C. Lactobacillus
D. Aspergillus
Answer: A. Rhizobium
Explanation:
Rhizobium forms a symbiotic relationship with legumes, fixing atmospheric nitrogen and converting it into a form that plants can absorb.
- The bacterium responsible for the production of the vitamin B12 in fermentation processes is:
A. Pseudomonas
B. Streptococcus
C. Propionibacterium shermanii
D. Escherichia coli
Answer: C. Propionibacterium shermanii
Explanation:
Propionibacterium shermanii is used in the fermentation process for the industrial production of vitamin B12, a crucial vitamin for human health.
- Which microbe is used for the production of citric acid on an industrial scale?
A. Rhizobium
B. Aspergillus niger
C. Clostridium
D. Azotobacter
Answer: B. Aspergillus niger
Explanation:
Aspergillus niger is extensively used for large-scale industrial production of citric acid, which is used in food, beverages, and as an industrial additive.
- In which of the following processes are microbes not involved?
A. Alcohol production
B. Antibiotic production
C. Photosynthesis in plants
D. Biogas production
Answer: C. Photosynthesis in plants
Explanation:
Photosynthesis in plants is carried out by plant chloroplasts (not microbes), whereas microbes are involved in processes like alcohol production, antibiotic production, and biogas formation.
- Which bacteria is involved in the formation of curd?
A. Lactobacillus bulgaricus
B. Clostridium butylicum
C. Pseudomonas syringae
D. Streptomyces griseus
Answer: A. Lactobacillus bulgaricus
Explanation:
Lactobacillus bulgaricus is commonly used in the fermentation of milk to form curd, by converting lactose into lactic acid.
- The use of which bacterium in agriculture results in nitrogen fixation in non-leguminous plants?
A. Rhizobium
B. Azospirillum
C. Aspergillus
D. Clostridium
Answer: B. Azospirillum
Explanation:
Azospirillum is a free-living nitrogen-fixing bacterium that enhances nitrogen availability in non-leguminous plants, often used in biofertilizers.
- Which microorganism is used in the production of single-cell protein (SCP)?
A. Streptococcus lactis
B. Methylophilus methylotrophus
C. Penicillium notatum
D. Azotobacter
Answer: B. Methylophilus methylotrophus
Explanation:
Methylophilus methylotrophus is used to produce single-cell proteins (SCP) due to its rapid growth rate and high protein content, which can serve as a protein-rich food supplement.
- Which organism is used to produce the antibiotic tetracycline?
A. Streptomyces aureofaciens
B. Penicillium notatum
C. Saccharomyces cerevisiae
D. Lactobacillus acidophilus
Answer: A. Streptomyces aureofaciens
Explanation:
Tetracycline is produced by Streptomyces aureofaciens, a bacterium, and is widely used as an antibiotic to treat bacterial infections.
- A microbial product that is used to suppress the immune system during organ transplants is:
A. Penicillin
B. Streptomycin
C. Cyclosporin A
D. Ethanol
Answer: C. Cyclosporin A
Explanation:
Cyclosporin A is an immunosuppressive agent produced by the fungus Trichoderma polysporum, used to prevent organ rejection after transplants.
- The microorganisms used to treat waste in septic tanks are primarily:
A. Viruses
B. Fungi
C. Bacteria
D. Algae
Answer: C. Bacteria
Explanation:
Septic tanks rely on bacteria to break down solid waste through anaerobic digestion, converting it into simpler substances.
- Bacillus thuringiensis is used in agricultural fields as:
A. Bioinsecticide
B. Biofertilizer
C. Antibiotic
D. Bioherbicide
Answer: A. Bioinsecticide
Explanation:
Bacillus thuringiensis (Bt) produces a toxin that kills insect larvae, making it a widely used bioinsecticide in organic and conventional farming.
- Which of the following produces lactic acid from glucose fermentation?
A. Streptococcus
B. Lactobacillus
C. Rhizobium
D. Penicillium
Answer: B. Lactobacillus
Explanation:
Lactobacillus bacteria convert glucose into lactic acid, a process that occurs during the production of yogurt and other fermented dairy products.
- What is the role of Saccharomyces cerevisiae in bread-making?
A. It converts sugar into acetic acid.
B. It produces carbon dioxide during fermentation.
C. It produces ethanol during fermentation.
D. It decomposes proteins into amino acids.
Answer: B. It produces carbon dioxide during fermentation.
Explanation:
In bread-making, Saccharomyces cerevisiae ferments sugars to produce carbon dioxide, which helps the dough rise and gives bread its light texture.
- The bacteria Pseudomonas putida is known for its use in:
A. Antibiotic production
B. Pollution control
C. Nitrogen fixation
D. Dairy fermentation
Answer: B. Pollution control
Explanation:
Pseudomonas putida is used in bioremediation to degrade pollutants such as hydrocarbons and oil spills, making it important in environmental pollution control.
- The enzyme used to break down starch into simple sugars in industries is produced by:
A. Aspergillus oryzae
B. Lactobacillus acidophilus
C. Rhizopus stolonifer
D. Penicillium notatum
Answer: A. Aspergillus oryzae
Explanation:
Aspergillus oryzae produces amylase, an enzyme that converts starch into simple sugars, used in brewing, baking, and biofuel production.
- A soil microorganism that plays a major role in organic matter decomposition is:
A. Streptomyces
B. Clostridium
C. Lactobacillus
D. Escherichia coli
Answer: A. Streptomyces
Explanation:
Streptomyces bacteria are important decomposers in soil, breaking down complex organic matter into simpler compounds, enriching soil fertility.
- What is the function of the bacterium Xanthomonas campestris in the food industry?
A. Production of lactic acid
B. Production of xanthan gum
C. Antibiotic production
D. Biogas production
Answer: B. Production of xanthan gum
Explanation:
Xanthomonas campestris produces xanthan gum, a polysaccharide used as a thickening agent and stabilizer in various food products like salad dressings and sauces.
- The microorganisms involved in the formation of humus are:
A. Algae
B. Fungi and bacteria
C. Viruses
D. Protozoa
Answer: B. Fungi and bacteria
Explanation:
Fungi and bacteria are key players in the decomposition of organic matter in soil, leading to the formation of humus, which enhances soil fertility.
- The microorganism used for commercial production of ethanol is:
A. Rhizobium
B. Saccharomyces cerevisiae
C. Penicillium
D. Streptococcus
Answer: B. Saccharomyces cerevisiae
Explanation:
Saccharomyces cerevisiae (yeast) is the primary organism used in the commercial fermentation process to convert sugars into ethanol, particularly in the production of alcoholic beverages and biofuels.
- Which bacterium is used in the biological treatment of sewage in wastewater treatment plants?
A. Pseudomonas putida
B. Rhizobium
C. Bacillus subtilis
D. Acetobacter aceti
Answer: A. Pseudomonas putida
Explanation:
Pseudomonas putida is used in sewage treatment plants due to its ability to break down various organic pollutants, enhancing the treatment process.
- Which bacterium is commonly used to produce bioinsecticides for agricultural purposes?
A. Azotobacter
B. Bacillus thuringiensis
C. Clostridium
D. Lactobacillus
Answer: B. Bacillus thuringiensis
Explanation:
Bacillus thuringiensis (Bt) produces a toxin that kills specific insect larvae and is used as a bioinsecticide, particularly in organic farming.
- The organism used in the production of the antibiotic penicillin is:
A. Penicillium notatum
B. Aspergillus niger
C. Rhizopus stolonifer
D. Saccharomyces cerevisiae
Answer: A. Penicillium notatum
Explanation:
Penicillium notatum was the first fungus identified by Alexander Fleming that produces penicillin, an antibiotic used to treat bacterial infections.
- Which microbe is used in the production of swiss cheese?
A. Aspergillus
B. Penicillium
C. Propionibacterium shermanii
D. Saccharomyces cerevisiae
Answer: C. Propionibacterium shermanii
Explanation:
Propionibacterium shermanii is involved in the fermentation process that creates swiss cheese, producing characteristic holes and a nutty flavor.
- Which microorganism is responsible for the spoilage of food by producing aflatoxins?
A. Aspergillus flavus
B. Saccharomyces cerevisiae
C. Penicillium notatum
D. Rhizopus stolonifer
Answer: A. Aspergillus flavus
Explanation:
Aspergillus flavus produces aflatoxins, toxic compounds that can contaminate food, particularly grains and nuts, leading to health risks.
- Which microorganism is used in the commercial production of acetic acid?
A. Acetobacter aceti
B. Saccharomyces cerevisiae
C. Lactobacillus
D. Clostridium
Answer: A. Acetobacter aceti
Explanation:
Acetobacter aceti is used to produce acetic acid (vinegar) by oxidizing ethanol, a process widely used in the food industry.
- The enzyme lipase is produced by which microorganism and is used in detergent industries?
A. Streptomyces
B. Penicillium
C. Aspergillus
D. Rhizopus
Answer: A. Streptomyces
Explanation:
Streptomyces species produce the enzyme lipase, which breaks down fats and is used in the detergent industry to remove oil and grease stains.
- Which of the following microorganisms is responsible for the fermentation of idli and dosa batter?
A. Saccharomyces cerevisiae
B. Lactobacillus
C. Leuconostoc mesenteroides
D. Streptococcus
Answer: C. Leuconostoc mesenteroides
Explanation:
Leuconostoc mesenteroides is responsible for the lactic acid fermentation in idli and dosa batter, giving it its characteristic sour taste.
- The bacterium used to remove sulfur from coal and petroleum is:
A. Thiobacillus ferrooxidans
B. Escherichia coli
C. Bacillus subtilis
D. Clostridium botulinum
Answer: A. Thiobacillus ferrooxidans
Explanation:
Thiobacillus ferrooxidans is used in biodesulfurization, a process that removes sulfur compounds from coal and petroleum to reduce pollution when these fuels are burned.
- In cheese production, which enzyme is used for coagulation of milk?
A. Lactase
B. Renin
C. Amylase
D. Lipase
Answer: B. Renin
Explanation:
Renin, also called rennet, is used in the cheese-making process to coagulate milk, separating it into curds and whey, the first step in cheese production.
- The gas produced during the fermentation process in the rumen of cattle is:
A. Oxygen
B. Methane
C. Hydrogen
D. Carbon dioxide
Answer: B. Methane
Explanation:
Microorganisms in the rumen of cattle produce methane as a byproduct of the fermentation process when they digest cellulose.
- Which of the following is used in the production of wine and beer?
A. Aspergillus
B. Saccharomyces cerevisiae
C. Lactobacillus
D. Pseudomonas
Answer: B. Saccharomyces cerevisiae
Explanation:
Saccharomyces cerevisiae is used in the fermentation process to produce alcohol in wine and beer by converting sugars into ethanol and carbon dioxide.
- The biogas plant’s primary microbe for methane production is:
A. Methanococcus
B. Azospirillum
C. Rhizobium
D. Lactobacillus
Answer: A. Methanococcus
Explanation:
Methanococcus is an archaeon that produces methane during anaerobic digestion of organic waste in biogas plants.
- The microorganism responsible for the synthesis of vitamin B2 (Riboflavin) is:
A. Clostridium
B. Ashbya gossypii
C. Aspergillus
D. Lactobacillus
Answer: B. Ashbya gossypii
Explanation:
Ashbya gossypii is a filamentous fungus used industrially to synthesize vitamin B2 (riboflavin), which is essential for energy metabolism.
- The fermentation of cocoa beans for chocolate production is carried out by:
A. Lactobacillus
B. Saccharomyces cerevisiae
C. Aspergillus
D. Leuconostoc
Answer: A. Lactobacillus
Explanation:
Lactobacillus species help in the fermentation process of cocoa beans, contributing to the development of chocolate’s flavor profile.
- Which microorganism is used in the commercial production of butanol?
A. Saccharomyces cerevisiae
B. Clostridium acetobutylicum
C. Lactobacillus bulgaricus
D. Penicillium notatum
Answer: B. Clostridium acetobutylicum
Explanation:
Clostridium acetobutylicum is used in the fermentation process to produce butanol, an important solvent and potential biofuel.
- Rhizobium forms a symbiotic relationship with:
A. Non-leguminous plants
B. Leguminous plants
C. Algae
D. Ferns
Answer: B. Leguminous plants
Explanation:
Rhizobium bacteria form symbiotic relationships with the roots of leguminous plants, where they fix atmospheric nitrogen into a form the plants can use.
- The bacterium used to produce insulin through genetic engineering is:
A. Escherichia coli
B. Streptococcus
C. Bacillus
D. Clostridium
Answer: A. Escherichia coli
Explanation:
Escherichia coli is genetically modified to produce human insulin, a major breakthrough in biotechnology used for diabetes treatment.
- Which of the following microorganisms is used in biological control of plant diseases?
A. Rhizobium
B. Trichoderma
C. Saccharomyces
D. Lactobacillus
Answer: B. Trichoderma
Explanation:
Trichoderma species are used in biological control as they can outcompete plant pathogens, helping to protect crops from diseases naturally.
- Which of the following microbes is used in making the traditional Japanese food “Natto”?
A. Bacillus subtilis
B. Saccharomyces cerevisiae
C. Lactobacillus bulgaricus
D. Penicillium roqueforti
Answer: A. Bacillus subtilis
Explanation:
Natto is made by fermenting soybeans using Bacillus subtilis, which gives the food its characteristic texture and flavor.
- The bacterium that converts alcohol to acetic acid in vinegar production is:
A. Saccharomyces cerevisiae
B. Lactobacillus
C. Acetobacter aceti
D. Penicillium notatum
Answer: C. Acetobacter aceti
Explanation:
Acetobacter aceti converts ethanol (alcohol) into acetic acid during the production of vinegar, a process of aerobic fermentation.
- A biofertilizer commonly used in paddy fields for nitrogen fixation is:
A. Streptococcus
B. Anabaena
C. Clostridium
D. Penicillium
Answer: B. Anabaena
Explanation:
Cyanobacteria like Anabaena fix atmospheric nitrogen in the soil, providing an essential nutrient for plants, particularly in paddy fields.
- The fungal species used in the ripening of blue cheese is:
A. Penicillium roqueforti
B. Rhizopus nigricans
C. Saccharomyces cerevisiae
D. Aspergillus oryzae
Answer: A. Penicillium roqueforti
Explanation:
Penicillium roqueforti is responsible for the characteristic blue veins in blue cheese, contributing to its flavor and texture.
- Azotobacter is known for:
A. Fermenting alcohol
B. Fixing nitrogen in legume root nodules
C. Fixing atmospheric nitrogen in soil
D. Producing antibiotics
Answer: C. Fixing atmospheric nitrogen in soil
Explanation:
Azotobacter is a free-living nitrogen-fixing bacterium that improves soil fertility by converting atmospheric nitrogen into a form that plants can use.
- The bacterium used for bioremediation of oil spills is:
A. Pseudomonas putida
B. Rhizobium
C. Penicillium
D. Lactobacillus
Answer: A. Pseudomonas putida
Explanation:
Pseudomonas putida can break down and degrade hydrocarbons in oil, making it useful for bioremediation of oil spills and other petroleum-based pollutants.
- Which of the following microbes is involved in the production of bioethanol?
A. Saccharomyces cerevisiae
B. Clostridium botulinum
C. Escherichia coli
D. Rhizopus stolonifer
Answer: A. Saccharomyces cerevisiae
Explanation:
Saccharomyces cerevisiae ferments sugars into ethanol, which is used in bioethanol production, a renewable energy source.
- The bacterium involved in converting milk to yogurt is:
A. Lactobacillus acidophilus
B. Escherichia coli
C. Bacillus subtilis
D. Penicillium notatum
Answer: A. Lactobacillus acidophilus
Explanation:
Lactobacillus acidophilus is a key bacterium in yogurt production, fermenting lactose to produce lactic acid, which thickens the milk and gives yogurt its tangy flavor.
- The fungus used in brewing soy sauce is:
A. Rhizopus
B. Aspergillus oryzae
C. Penicillium
D. Saccharomyces cerevisiae
Answer: B. Aspergillus oryzae
Explanation:
Aspergillus oryzae is used in the fermentation process of soybeans and wheat to produce soy sauce, an essential component in Asian cuisine.
- Which microorganism is used to produce vitamin C (ascorbic acid) industrially?
A. Gluconobacter oxydans
B. Lactobacillus bulgaricus
C. Saccharomyces cerevisiae
D. Rhizopus stolonifer
Answer: A. Gluconobacter oxydans
Explanation:
Gluconobacter oxydans is used in the industrial production of vitamin C, converting sorbitol into sorbose, a precursor in ascorbic acid synthesis.
- The bacterium used in vinegar production is:
A. Acetobacter aceti
B. Escherichia coli
C. Bacillus subtilis
D. Streptomyces griseus
Answer: A. Acetobacter aceti
Explanation:
Acetobacter aceti converts ethanol to acetic acid in an aerobic fermentation process, producing vinegar.
- Which bacterium is used in the production of bioplastics?
A. Bacillus subtilis
B. Pseudomonas putida
C. Rhodobacter sphaeroides
D. Escherichia coli
Answer: B. Pseudomonas putida
Explanation:
Pseudomonas putida is genetically engineered to produce polyhydroxyalkanoates (PHAs), a biodegradable plastic used as an alternative to petroleum-based plastics.
- The biofertilizer used to promote the growth of leguminous crops is:
A. Azospirillum
B. Rhizobium
C. Clostridium
D. Pseudomonas
Answer: B. Rhizobium
Explanation:
Rhizobium forms nodules in the roots of leguminous plants and fixes atmospheric nitrogen, improving soil fertility and promoting plant growth.
- Which microorganism is used in the production of vitamin B12?
A. Propionibacterium shermanii
B. Saccharomyces cerevisiae
C. Lactobacillus
D. Bacillus
Answer: A. Propionibacterium shermanii
Explanation:
Propionibacterium shermanii is used in the industrial production of vitamin B12, which is essential for red blood cell formation and neurological function.
- The microorganism used in biological nitrogen fixation in paddy fields is:
A. Anabaena
B. Azotobacter
C. Clostridium
D. Escherichia coli
Answer: A. Anabaena
Explanation:
Cyanobacteria such as Anabaena are used in paddy fields for biological nitrogen fixation, enriching the soil with nitrogen for rice cultivation.
- Which of the following is a methane-producing archaea found in biogas plants?
A. Methanobacterium
B. Rhizobium
C. Lactobacillus
D. Pseudomonas
Answer: A. Methanobacterium
Explanation:
Methanobacterium is an archaea involved in the anaerobic digestion of organic matter, producing methane in biogas plants.
- The microorganism used in the production of ethanol from molasses is:
A. Clostridium botulinum
B. Escherichia coli
C. Saccharomyces cerevisiae
D. Pseudomonas aeruginosa
Answer: C. Saccharomyces cerevisiae
Explanation:
Saccharomyces cerevisiae is used to ferment sugars in molasses to produce ethanol, which is used in alcoholic beverages and as biofuel.
- Which microorganism is used for the production of citric acid on a commercial scale?
A. Aspergillus niger
B. Penicillium notatum
C. Rhizopus nigricans
D. Escherichia coli
Answer: A. Aspergillus niger
Explanation:
Aspergillus niger is employed in the industrial production of citric acid, a widely used preservative and flavoring agent.
- Which microorganism is used in the industrial production of glutamic acid, a component of MSG (Monosodium Glutamate)?
A. Corynebacterium glutamicum
B. Bacillus subtilis
C. Escherichia coli
D. Rhizobium
Answer: A. Corynebacterium glutamicum
Explanation:
Corynebacterium glutamicum is used for large-scale production of glutamic acid, which is a key component of monosodium glutamate (MSG), a flavor enhancer.
- The fermentation process of sourdough bread involves which microorganism?
A. Lactobacillus sanfranciscensis
B. Aspergillus niger
C. Saccharomyces cerevisiae
D. Rhizopus stolonifer
Answer: A. Lactobacillus sanfranciscensis
Explanation:
Lactobacillus sanfranciscensis is responsible for the lactic acid fermentation in sourdough bread, giving it its tangy flavor and texture.
- The microorganism involved in the production of biogas is:
A. Lactobacillus acidophilus
B. Methanobacterium
C. Pseudomonas putida
D. Saccharomyces cerevisiae
Answer: B. Methanobacterium
Explanation:
Methanobacterium plays a key role in the anaerobic digestion process in biogas plants, producing methane gas as a renewable energy source.
- Which of the following microbes is used in the production of protease enzymes in the detergent industry?
A. Bacillus licheniformis
B. Aspergillus oryzae
C. Rhizopus stolonifer
D. Lactobacillus bulgaricus
Answer: A. Bacillus licheniformis
Explanation:
Bacillus licheniformis is used in the production of protease enzymes, which are added to detergents to break down proteins and remove stains.
- The microorganism responsible for the spoilage of bread by causing mold is:
A. Penicillium notatum
B. Rhizopus stolonifer
C. Aspergillus niger
D. Lactobacillus
Answer: B. Rhizopus stolonifer
Explanation:
Rhizopus stolonifer is a fungus that causes mold on bread, leading to its spoilage by decomposing the carbohydrates.
- The microorganism used to produce alcohol-free beer is:
A. Saccharomyces cerevisiae
B. Saccharomyces pastorianus
C. Lactobacillus
D. Escherichia coli
Answer: B. Saccharomyces pastorianus
Explanation:
Saccharomyces pastorianus is a yeast strain used in brewing processes to produce low-alcohol or alcohol-free beer by reducing ethanol production during fermentation.
- Which bacterium is used in the conversion of ammonia to nitrate in the nitrogen cycle?
A. Nitrosomonas
B. Azotobacter
C. Rhizobium
D. Pseudomonas
Answer: A. Nitrosomonas
Explanation:
Nitrosomonas bacteria oxidize ammonia into nitrite, an important step in the nitrification process of the nitrogen cycle.
- The bacterium used for the production of single-cell protein (SCP) is:
A. Chlorella
B. Candida utilis
C. Rhizopus
D. Saccharomyces cerevisiae
Answer: B. Candida utilis
Explanation:
Candida utilis is a yeast used in the production of single-cell protein, which is a protein-rich food source derived from microbial cells.
- The fungus that produces the enzyme amylase for the conversion of starch into sugars is:
A. Aspergillus oryzae
B. Penicillium notatum
C. Rhizopus stolonifer
D. Saccharomyces cerevisiae
Answer: A. Aspergillus oryzae
Explanation:
Aspergillus oryzae produces the enzyme amylase, which breaks down starches into simpler sugars, and is used in food processing industries like brewing.
- Which microbe is used to produce antibiotics like streptomycin?
A. Streptomyces griseus
B. Bacillus subtilis
C. Penicillium notatum
D. Escherichia coli
Answer: A. Streptomyces griseus
Explanation:
Streptomyces griseus is a soil bacterium that produces the antibiotic streptomycin, which is used to treat bacterial infections.
- The bacterium used in the production of acetic acid from ethanol is:
A. Acetobacter aceti
B. Escherichia coli
C. Bacillus subtilis
D. Streptomyces griseus
Answer: A. Acetobacter aceti
Explanation:
Acetobacter aceti oxidizes ethanol into acetic acid, a process used in the production of vinegar.
- The fungus responsible for the fermentation process in tempeh production is:
A. Rhizopus oligosporus
B. Aspergillus oryzae
C. Penicillium notatum
D. Saccharomyces cerevisiae
Answer: A. Rhizopus oligosporus
Explanation:
Rhizopus oligosporus is used to ferment soybeans into tempeh, a traditional Indonesian food rich in protein.
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