Fermentation is a core bioprocess in pharmaceutics, covering principles and general requirements essential for B. Pharm students. Understanding microbial metabolism, substrate specificity, oxygen transfer, aeration and agitation, pH and temperature control, inoculum development, sterility, and bioreactor design enables efficient production of pharmaceuticals, enzymes, antibiotics and metabolites. Key concepts include batch, fed‑batch and continuous modes, yield, productivity, downstream processing and quality control. Practical knowledge of monitoring parameters, contamination prevention, scale‑up and aseptic techniques bridges theory with industry practice. This concise, keyword‑rich guide emphasizes fermentation principles, process parameters and regulatory considerations. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which parameter is most critical for aerobic fermentation to ensure sufficient oxygen supply?
- pH control
- Oxygen transfer rate
- Sterilization time
- Inoculum age
Correct Answer: Oxygen transfer rate
Q2. In fermentation, which growth phase is characterized by rapid cell division and exponential increase in biomass?
- Lag phase
- Stationary phase
- Death phase
- Log phase
Correct Answer: Log phase
Q3. Which cultivation mode allows continuous feed of fresh medium and removal of culture to maintain steady state?
- Batch fermentation
- Fed-batch fermentation
- Continuous fermentation (chemostat)
- Solid-state fermentation
Correct Answer: Continuous fermentation (chemostat)
Q4. What is the main purpose of an inoculum in a fermentation process?
- To sterilize the bioreactor
- To introduce a defined active culture for predictable growth
- To adjust pH
- To remove metabolic byproducts
Correct Answer: To introduce a defined active culture for predictable growth
Q5. Which factor directly affects microbial enzyme activity and fermentation rate?
- Ambient light intensity
- pH and temperature
- Color of medium
- Size of fermentation vessel label
Correct Answer: pH and temperature
Q6. What is a common indicator used to estimate biomass concentration in microbial cultures?
- Optical density at 600 nm (OD600)
- Refractive index
- pH meter reading
- Conductivity
Correct Answer: Optical density at 600 nm (OD600)
Q7. Which sterilization method is most commonly used for fermenter media and equipment in pharmaceutical fermentation?
- Gamma irradiation
- Autoclaving (moist heat)
- Dry heat at 160°C
- Ultraviolet light
Correct Answer: Autoclaving (moist heat)
Q8. In fed-batch fermentation, why is substrate fed gradually instead of all at once?
- To speed up sterilization
- To prevent substrate inhibition and control growth rate
- To increase evaporation
- To reduce aeration needs
Correct Answer: To prevent substrate inhibition and control growth rate
Q9. Which measurement best indicates dissolved oxygen availability in a bioreactor?
- pO2 probe reading in culture broth
- CO2 solubility
- Optical density
- Redox potential of sterilized medium
Correct Answer: pO2 probe reading in culture broth
Q10. What is the role of agitation in fermentation?
- To cool the incubator only
- To mix medium, improve oxygen transfer and maintain homogeneity
- To sterilize the air supply
- To feed the inoculum
Correct Answer: To mix medium, improve oxygen transfer and maintain homogeneity
Q11. Which organism type is commonly used for recombinant protein production in pharma fermentation?
- Saccharomyces cerevisiae
- Escherichia coli
- Penicillium chrysogenum
- Both Escherichia coli and Saccharomyces cerevisiae
Correct Answer: Both Escherichia coli and Saccharomyces cerevisiae
Q12. What does yield in fermentation usually refer to?
- Volume of culture per liter of air
- Amount of product formed per unit substrate consumed
- Duration of fermentation
- Inoculum viability percentage
Correct Answer: Amount of product formed per unit substrate consumed
Q13. Which parameter is most important to control to prevent contamination during fermentation?
- Medium color
- Sterility and aseptic technique
- Length of tubing labels
- Ambient noise level
Correct Answer: Sterility and aseptic technique
Q14. What is downstream processing in fermentation?
- Preparing the inoculum
- Steps for product recovery and purification after fermentation
- Controlling pH during growth
- Calibration of pH electrode
Correct Answer: Steps for product recovery and purification after fermentation
Q15. Which kinetic model describes microbial growth rate proportional to biomass concentration?
- Zero-order kinetics
- First-order kinetics
- Monod model
- Henderson-Hasselbalch equation
Correct Answer: Monod model
Q16. What is a primary metabolite in fermentation?
- A compound produced only during stationary phase
- A metabolite essential for growth produced during active growth
- An antibiotic produced in secondary metabolism
- A contaminant from medium components
Correct Answer: A metabolite essential for growth produced during active growth
Q17. Which control strategy helps maintain pH in a bioreactor?
- Manual stirring only
- Automatic addition of acid or alkali based on pH probe
- Changing the vessel color
- Increasing inoculum size
Correct Answer: Automatic addition of acid or alkali based on pH probe
Q18. What is the most common unit for reporting dissolved oxygen in fermentation?
- mg L-1 or % saturation
- Degrees Celsius
- Optical density units
- CFU per mL
Correct Answer: mg L-1 or % saturation
Q19. Which factor is a primary cause of foam formation in aerated fermentations?
- Excessive inoculum volume
- Proteinaceous compounds and vigorous aeration
- Low medium pH only
- Sterile conditions
Correct Answer: Proteinaceous compounds and vigorous aeration
Q20. In scale-up of fermentation, which dimensionless number is important for maintaining similar mixing and mass transfer?
- Piston efficiency number
- Reynolds number
- Boiling point
- ISO code
Correct Answer: Reynolds number
Q21. What is the main advantage of continuous fermentation over batch fermentation?
- Easier sterilization
- Higher productivity and steady state operation
- No need for monitoring
- Lower risk of contamination
Correct Answer: Higher productivity and steady state operation
Q22. Which assay is commonly used to estimate viable cell count in a fermentation culture?
- Gram staining
- Colony forming units by plate count
- pH titration
- Refractive index
Correct Answer: Colony forming units by plate count
Q23. What is metabolic overflow in fermentation?
- When cells cease metabolism entirely
- Excess substrate leads to formation of byproducts like acetate
- Complete conversion of substrate to product
- Leakage of medium from vessel
Correct Answer: Excess substrate leads to formation of byproducts like acetate
Q24. Which component of medium provides nitrogen for microbial growth?
- Carbon source like glucose
- Nitrogen source like ammonium salts or peptone
- Trace metals only
- Antifoam agents
Correct Answer: Nitrogen source like ammonium salts or peptone
Q25. Which technique is used to monitor contamination during fermentation without opening the vessel?
- Regular plating only
- Microscopic observation through sampling port
- Sterility cannot be monitored
- Bioreactor inline sensors and periodic sampling under aseptic conditions
Correct Answer: Bioreactor inline sensors and periodic sampling under aseptic conditions
Q26. What is the function of an antifoam agent in fermentation?
- Promote foam formation
- Suppress and collapse foam to prevent overflow and gas transfer issues
- Act as carbon source
- Sterilize the medium
Correct Answer: Suppress and collapse foam to prevent overflow and gas transfer issues
Q27. Which of the following is a secondary metabolite typically produced in stationary phase?
- Biomass
- Antibiotics like penicillin
- Glucose
- Ribosomal RNA
Correct Answer: Antibiotics like penicillin
Q28. What does specific productivity (qP) represent in fermentation?
- Total product per batch
- Rate of product formation per unit biomass
- Volume of medium per liter of air
- Number of viable cells
Correct Answer: Rate of product formation per unit biomass
Q29. Which gas is commonly measured to assess metabolic activity in aerobic fermentations?
- Helium
- Carbon dioxide evolution rate (CER)
- Argon
- Ozone
Correct Answer: Carbon dioxide evolution rate (CER)
Q30. For regulatory compliance in pharmaceutical fermentation, which documentation is essential?
- Batch records, SOPs and validation reports
- Only email communications
- Informal lab notes without signatures
- Marketing brochures
Correct Answer: Batch records, SOPs and validation reports
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