Introduction: The industrial use of microbes and production of enzymes is a core topic for B.Pharm students, covering microbial fermentation, bioreactor design, upstream and downstream processing, and enzyme applications in pharmaceuticals. Understanding strain improvement, recombinant expression, immobilization techniques, enzyme assays, purification methods and regulatory principles (GMP, GRAS organisms) is essential for drug development, biocatalysis and quality-controlled enzyme manufacture. Key industrial enzymes include amylases, proteases, lipases and cellulases, used for synthesis, formulation and diagnostics. Practical skills in optimizing temperature, pH, aeration, agitation and stabilizers ensure high yield and activity. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary difference between submerged fermentation (SmF) and solid-state fermentation (SSF)?
- SmF uses free-flowing liquid medium while SSF uses solid substrate with low moisture
- SmF is used only for fungi and SSF only for bacteria
- SSF requires continuous stirring while SmF is static
- SSF always produces higher purity enzymes than SmF
Correct Answer: SmF uses free-flowing liquid medium while SSF uses solid substrate with low moisture
Q2. Which organism is commonly classified as GRAS and widely used for industrial enzyme production?
- Escherichia coli
- Saccharomyces cerevisiae
- Pseudomonas aeruginosa
- Bacillus cereus
Correct Answer: Saccharomyces cerevisiae
Q3. Which parameter most directly affects oxygen transfer rates in aerobic bioreactors?
- Medium osmolarity
- kLa (volumetric mass transfer coefficient)
- Buffer concentration
- Light intensity
Correct Answer: kLa (volumetric mass transfer coefficient)
Q4. Immobilization of enzymes is mainly used to achieve which advantage?
- Increase molecular weight of enzymes
- Enhance enzyme reuse and stability
- Convert enzymes to antibiotics
- Eliminate need for cofactors
Correct Answer: Enhance enzyme reuse and stability
Q5. Which method is a covalent immobilization technique for enzymes?
- Physical adsorption on activated carbon
- Covalent binding to activated agarose
- Entrapment in calcium alginate beads
- Cross-flow ultrafiltration concentration
Correct Answer: Covalent binding to activated agarose
Q6. In downstream processing of enzymes, which step typically precedes chromatographic purification?
- Product formulation
- Cell harvest and primary separation
- Lyophilization of final product
- Regulatory submission
Correct Answer: Cell harvest and primary separation
Q7. Which enzyme class does amylase belong to according to EC classification?
- Oxidoreductases
- Transferases
- Hydrolases
- Isomerases
Correct Answer: Hydrolases
Q8. For recombinant production of human insulin, which host is commonly used to obtain high yields quickly?
- Escherichia coli
- Penicillium chrysogenum
- Human cell lines only
- Clostridium botulinum
Correct Answer: Escherichia coli
Q9. Which technique is best for concentrating crude enzyme solutions before chromatography?
- Ion exchange chromatography
- Ultrafiltration
- Thin layer chromatography
- Direct lyophilization without concentration
Correct Answer: Ultrafiltration
Q10. What is a common stabilizer used to preserve enzyme activity during storage?
- SDS (sodium dodecyl sulfate)
- Glycerol
- Mercuric chloride
- Acetone
Correct Answer: Glycerol
Q11. Which of the following is a primary metabolite often produced in industrial fermentation?
- Antibiotics
- Vitamins
- Organic acids like citric acid
- Secondary alkaloids
Correct Answer: Organic acids like citric acid
Q12. What is one major regulatory concern when producing enzymes for pharmaceutical use?
- Color of the fermentation broth
- Endotoxin levels and GMP compliance
- Using non-sterile water for fermentation
- Adding antibiotics to final product
Correct Answer: Endotoxin levels and GMP compliance
Q13. Which purification technique exploits specific binding between an enzyme and a ligand?
- Ion-exchange chromatography
- Size-exclusion chromatography
- Affinity chromatography
- Precipitation with ammonium sulfate only
Correct Answer: Affinity chromatography
Q14. A low Km value for an enzyme indicates what about its substrate affinity?
- Low affinity for substrate
- High affinity for substrate
- Low catalytic turnover
- Non-specific binding
Correct Answer: High affinity for substrate
Q15. Which of the following is a common method to improve microbial strains for higher enzyme yield?
- Adaptive laboratory evolution and genetic engineering
- Using lower-quality substrate
- Reducing oxygen supply intentionally
- Avoiding selection pressure
Correct Answer: Adaptive laboratory evolution and genetic engineering
Q16. Cross-linked enzyme aggregates (CLEAs) are an example of which immobilization approach?
- Adsorption
- Entrapment
- Carrier-free cross-linking
- Simple dialysis
Correct Answer: Carrier-free cross-linking
Q17. Which physical parameter is most critical to control for thermostable enzymes from thermophiles?
- Light exposure
- Temperature
- Magnetic field
- pH only at 2.0
Correct Answer: Temperature
Q18. In an industrial stirred-tank bioreactor, increasing agitation primarily improves which of the following?
- Antibiotic resistance
- Heat generation only
- Mass transfer and mixing
- Product color
Correct Answer: Mass transfer and mixing
Q19. Which cofactor is commonly required by dehydrogenase enzymes?
- NAD+ or NADP+
- PMSF
- EDTA
- SDS
Correct Answer: NAD+ or NADP+
Q20. Which enzyme assay parameter indicates enzyme purity?
- Total protein concentration only
- Specific activity (activity per mg protein)
- pH of the assay buffer only
- Colorimetric readout without normalization
Correct Answer: Specific activity (activity per mg protein)
Q21. What is the main disadvantage of using Escherichia coli for secreting eukaryotic enzymes?
- It secretes too many glycosylated proteins
- Limited secretion pathways and lack of eukaryotic glycosylation
- Excessive production of complex polysaccharides
- It cannot grow in bioreactors
Correct Answer: Limited secretion pathways and lack of eukaryotic glycosylation
Q22. Which of the following inhibitors competes with substrate for the active site?
- Non-competitive inhibitor
- Uncompetitive inhibitor
- Competitive inhibitor
- Allosteric activator
Correct Answer: Competitive inhibitor
Q23. Which downstream step is used to remove cell debris after fermentation?
- Filtration or centrifugation
- Affinity chromatography
- Ion exchange equilibration
- Spray drying
Correct Answer: Filtration or centrifugation
Q24. Why are thermostable enzymes advantageous in industrial processes?
- Higher reaction rates and greater process stability at elevated temperatures
- They require refrigeration
- They denature easily, allowing single-use applications
- They always eliminate the need for cofactors
Correct Answer: Higher reaction rates and greater process stability at elevated temperatures
Q25. Which analytical method is commonly used to estimate molecular weight and purity of enzymes?
- SDS-PAGE
- pH titration only
- ELISA without standards
- Optical density at 260 nm
Correct Answer: SDS-PAGE
Q26. Which of the following is a common precipitant used for enzyme fractionation?
- Ammonium sulfate
- Benzene
- Hydrochloric acid
- Methanol at 100°C
Correct Answer: Ammonium sulfate
Q27. What is the role of foaming control (antifoam) in aerobic fermentations?
- To increase foam for better oxygen transfer
- To suppress foam formation and prevent contamination or overflow
- To sterilize the medium
- To act as a carbon source
Correct Answer: To suppress foam formation and prevent contamination or overflow
Q28. Which host is preferred when correct glycosylation of therapeutic enzymes is required?
- Escherichia coli
- Saccharomyces cerevisiae or mammalian cells
- Bacillus subtilis always
- Thermus aquaticus
Correct Answer: Saccharomyces cerevisiae or mammalian cells
Q29. Which statement best describes downstream processing cost impact in enzyme manufacturing?
- Downstream processing is usually negligible in overall cost
- Downstream processing can account for a large fraction of total production cost
- Upstream costs always exceed downstream by tenfold
- Packaging determines the majority of cost
Correct Answer: Downstream processing can account for a large fraction of total production cost
Q30. What is the most important reason for using aseptic technique during industrial fermentation?
- To increase evaporation
- To prevent contamination that reduces yield and product quality
- To change pH automatically
- To color the final product
Correct Answer: To prevent contamination that reduces yield and product quality
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
Mail- Sachin@pharmacyfreak.com