Q.1 Which microorganism is primarily used for the commercial production of ethanol?
Escherichia coli
Saccharomyces cerevisiae
Bacillus subtilis
Lactobacillus acidophilus
Explanation - Saccharomyces cerevisiae (baker's yeast) ferments sugars to produce ethanol and carbon dioxide, widely used in alcoholic beverage and biofuel production.
Correct answer is: Saccharomyces cerevisiae
Q.2 Penicillin, an antibiotic, is produced industrially by which organism?
Penicillium chrysogenum
Aspergillus niger
Streptomyces griseus
Clostridium tetani
Explanation - Penicillin is obtained from the mold Penicillium chrysogenum, which produces the antibiotic as a secondary metabolite.
Correct answer is: Penicillium chrysogenum
Q.3 Which type of fermentation is primarily used in the production of citric acid?
Alcoholic fermentation
Lactic acid fermentation
Oxidative fermentation
Submerged fermentation
Explanation - Citric acid is industrially produced using submerged fermentation by Aspergillus niger in large fermenters.
Correct answer is: Submerged fermentation
Q.4 The process of scaling up microbial production from lab to industrial scale is called:
Sterilization
Upstream processing
Downstream processing
Bioreactor optimization
Explanation - Upstream processing includes cultivation, growth optimization, and scaling up microbes before product extraction.
Correct answer is: Upstream processing
Q.5 Rennet used in cheese production is primarily obtained from:
Bacteria
Fungi
Animal stomachs or recombinant microbes
Algae
Explanation - Rennet contains the enzyme chymosin, traditionally obtained from calf stomachs or produced via genetically engineered microbes.
Correct answer is: Animal stomachs or recombinant microbes
Q.6 Which microorganism is used in the industrial production of citric acid?
Aspergillus niger
Penicillium notatum
Saccharomyces cerevisiae
Bacillus subtilis
Explanation - Aspergillus niger is favored for citric acid production because of its high yield and adaptability to submerged fermentation.
Correct answer is: Aspergillus niger
Q.7 Single-cell protein production primarily uses which type of organism?
Algae, bacteria, and fungi
Protozoa
Viruses
Parasitic worms
Explanation - Single-cell proteins are derived from microbial biomass such as algae, yeast, and bacteria as a protein supplement.
Correct answer is: Algae, bacteria, and fungi
Q.8 Which process is crucial in industrial enzyme production for high yield?
Fermentation
Sterilization
Pasteurization
Lyophilization
Explanation - Fermentation allows microorganisms to grow and produce enzymes in controlled conditions, essential for industrial scale.
Correct answer is: Fermentation
Q.9 Which organism is commonly used for the production of antibiotics like streptomycin?
Streptomyces griseus
Bacillus subtilis
Saccharomyces cerevisiae
Aspergillus niger
Explanation - Streptomyces species are filamentous bacteria known for producing many antibiotics, including streptomycin.
Correct answer is: Streptomyces griseus
Q.10 Downstream processing in industrial microbiology refers to:
Product extraction and purification
Microbial cultivation
Sterilization of equipment
Scaling up fermentation
Explanation - Downstream processing involves recovering and purifying the product after microbial fermentation.
Correct answer is: Product extraction and purification
Q.11 Which sugar is most commonly used as a substrate for ethanol fermentation?
Glucose
Sucrose
Fructose
Lactose
Explanation - Glucose is easily metabolized by Saccharomyces cerevisiae during alcoholic fermentation to produce ethanol.
Correct answer is: Glucose
Q.12 Which microorganism is used in the production of vinegar?
Acetobacter aceti
Saccharomyces cerevisiae
Lactobacillus bulgaricus
Penicillium chrysogenum
Explanation - Acetobacter aceti oxidizes ethanol to acetic acid, the main component of vinegar.
Correct answer is: Acetobacter aceti
Q.13 Which is an example of a secondary metabolite with industrial importance?
Penicillin
Glucose
Amino acids
Fatty acids
Explanation - Secondary metabolites like antibiotics are produced during the stationary phase and are not essential for microbial growth.
Correct answer is: Penicillin
Q.14 The use of microbes to detoxify industrial waste is called:
Bioremediation
Fermentation
Pasteurization
Sterilization
Explanation - Bioremediation employs microorganisms to degrade pollutants and clean up industrial or environmental waste.
Correct answer is: Bioremediation
Q.15 Which organism is used in industrial production of lactic acid?
Lactobacillus spp.
Bacillus subtilis
Aspergillus niger
Saccharomyces cerevisiae
Explanation - Lactic acid bacteria ferment carbohydrates to produce lactic acid, widely used in food and pharmaceutical industries.
Correct answer is: Lactobacillus spp.
Q.16 Immobilized enzyme technology is advantageous because:
Enzymes can be reused
Enzyme activity is reduced
Requires continuous microbial growth
Substrate becomes toxic
Explanation - Immobilized enzymes are fixed on supports, allowing repeated use and stability in industrial processes.
Correct answer is: Enzymes can be reused
Q.17 Which factor is most critical for high-yield antibiotic production in fermentation?
pH and temperature
Light intensity
Color of the medium
Volume of air only
Explanation - Optimal pH and temperature are critical for microbial metabolism and secondary metabolite production, including antibiotics.
Correct answer is: pH and temperature
Q.18 Which microorganism is used for industrial production of acetone and butanol?
Clostridium acetobutylicum
Saccharomyces cerevisiae
Bacillus subtilis
Penicillium chrysogenum
Explanation - Clostridium acetobutylicum ferments sugars into acetone, butanol, and ethanol in a process known as ABE fermentation.
Correct answer is: Clostridium acetobutylicum
Q.19 Which is the primary goal of upstream processing in industrial microbiology?
Optimizing microbial growth and metabolite production
Purifying the product
Packaging the final product
Waste management
Explanation - Upstream processing involves preparing the growth medium, inoculum, and conditions for maximum microbial product yield.
Correct answer is: Optimizing microbial growth and metabolite production
Q.20 Citric acid production by Aspergillus niger is optimized by maintaining:
Low pH
High pH
Neutral pH
Alkaline pH
Explanation - A low pH (around 2-3) favors citric acid accumulation and prevents contamination by unwanted microbes.
Correct answer is: Low pH
Q.21 Which of the following is an example of a microbial starter used in industrial food fermentation?
Lactobacillus in yogurt
Escherichia coli in water
Streptococcus pneumoniae in cheese
Clostridium tetani in vinegar
Explanation - Lactobacillus species ferment lactose to lactic acid, acting as starter cultures in yogurt production.
Correct answer is: Lactobacillus in yogurt
Q.22 Industrial-scale enzyme production often prefers which fermentation method?
Submerged fermentation
Solid-state fermentation
Photofermentation
Batch culture without aeration
Explanation - Submerged fermentation allows better control of pH, temperature, and oxygen, making it suitable for large-scale enzyme production.
Correct answer is: Submerged fermentation
Q.23 Which microorganism is used for industrial production of vitamin B12?
Propionibacterium freudenreichii
Saccharomyces cerevisiae
Bacillus subtilis
Aspergillus niger
Explanation - Propionibacterium species produce vitamin B12 through fermentation, important for supplement production.
Correct answer is: Propionibacterium freudenreichii
Q.24 Which of the following is a major challenge in industrial microbiology?
Contamination control
Sunlight exposure
Color of fermenter
Soil pH
Explanation - Industrial fermentation requires strict aseptic conditions to prevent contamination, which can reduce yield or spoil products.
Correct answer is: Contamination control
Q.25 The term 'secondary metabolite' refers to:
Compounds not directly involved in growth
Primary nutrients
Energy molecules
Structural proteins
Explanation - Secondary metabolites, such as antibiotics, are produced after the growth phase and are not essential for basic microbial growth.
Correct answer is: Compounds not directly involved in growth