Industrial production of penicillin MCQs With Answer

Industrial production of penicillin is a vital subject for B.Pharm students, integrating microbiology, fermentation technology, and downstream processing. This concise overview emphasizes Penicillium chrysogenum strain selection and improvement, submerged fermentation in stirred-tank bioreactors, medium optimization (carbon/nitrogen sources, corn steep liquor, precursors like phenylacetic acid), aeration/agitation, kLa and oxygen transfer, antifoam control, and solvent extraction/crystallization for purification. It also covers fed-batch strategies, analytical methods (bioassay, HPLC), process scale-up, and quality assurance to maximize antibiotic yield. Mastering these keywords—penicillin production, fermentation, downstream processing, strain improvement, and penicillin G—will strengthen your practical and theoretical understanding. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary industrial organism used for commercial penicillin production?

• Penicillium chrysogenum
• Penicillium notatum
• Aspergillus niger
• Streptomyces griseus

Correct Answer: Penicillium chrysogenum

Q2. Which fermentation mode is most commonly used for large-scale penicillin manufacturing?

• Surface fermentation
• Solid-state fermentation
• Submerged (deep-tank) fermentation
• Photo-bioreactor fermentation

Correct Answer: Submerged (deep-tank) fermentation

Q3. Which precursor is added to produce penicillin G (benzylpenicillin) in industry?

• Phenylacetic acid
• Benzoic acid
• Acetic acid
• Phenylalanine

Correct Answer: Phenylacetic acid

Q4. Which nitrogen source is commonly used to enhance penicillin production?

• Corn steep liquor
• Ammonium nitrate
• Casein hydrolysate
• Soy peptone

Correct Answer: Corn steep liquor

Q5. Which carbon source is preferred to avoid catabolite repression in penicillin fermentation?

• Glucose
• Lactose
• Sucrose
• Maltose

Correct Answer: Lactose

Q6. What is the primary downstream recovery method used to separate penicillin from fermentation broth?

• Solvent extraction and crystallization
• Membrane ultrafiltration only
• Drying and direct milling
• Lyophilization without extraction

Correct Answer: Solvent extraction and crystallization

Q7. Which strategy most directly increases the volumetric oxygen transfer coefficient (kLa) in a bioreactor?

• Increase inoculum size
• Increase agitation and aeration
• Decrease temperature significantly
• Add more nitrogen source

Correct Answer: Increase agitation and aeration

Q8. Why is fed-batch operation commonly used in industrial penicillin fermentation?

• To maintain continuous product removal
• To control substrate concentration and enhance penicillin yield
• To enable phototrophic growth
• To prevent pellet formation

Correct Answer: To control substrate concentration and enhance penicillin yield

Q9. Which enzyme is used industrially to obtain 6-aminopenicillanic acid (6-APA) from penicillin G?

• Penicillin acylase
• Beta-lactamase
• Transaminase
• Acyl transferase

Correct Answer: Penicillin acylase

Q10. What is a typical fermentation temperature used for optimal penicillin production?

• 37 °C
• 30 °C
• 25 °C
• 15 °C

Correct Answer: 25 °C

Q11. What is the role of calcium carbonate (CaCO3) in many penicillin production media?

• Source of calcium for cell wall synthesis
• Buffering agent to maintain pH
• Primary carbon source
• Antifoam agent

Correct Answer: Buffering agent to maintain pH

Q12. What is a likely consequence of excessive agitation in penicillin fermentation?

• Improved pellet formation and higher yield
• Shear damage to mycelium reducing penicillin yield
• Lower dissolved oxygen
• Elimination of catabolite repression

Correct Answer: Shear damage to mycelium reducing penicillin yield

Q13. Which analytical method gives precise quantitative measurement of penicillin concentration in downstream processing?

• Microbiological zone of inhibition assay
• HPLC (High-performance liquid chromatography)
• Simple UV-visible colorimetric test
• Light microscopy

Correct Answer: HPLC (High-performance liquid chromatography)

Q14. How is foam typically controlled during large-scale penicillin fermentations?

• Increase aeration to burst foam
• Use antifoam agents
• Lower pH to acidic extremes
• Add phenylacetic acid as defoamer

Correct Answer: Use antifoam agents

Q15. Which mycelial morphology is generally associated with high penicillin productivity in submerged culture?

• Dispersed filamentous growth
• Pelleted mycelial morphology
• Biofilm on baffles
• Yeast-like budding

Correct Answer: Pelleted mycelial morphology

Q16. Which parameter is most critical for oxygen supply during scale-up of penicillin fermentation?

• pH control set point
• kLa (volumetric oxygen transfer coefficient)
• Seed culture age only
• Concentration of antifoam

Correct Answer: kLa (volumetric oxygen transfer coefficient)

Q17. What causes catabolite repression of penicillin biosynthesis?

• High dissolved oxygen levels
• High glucose concentration
• Low agitation speed
• Excessive antifoam

Correct Answer: High glucose concentration

Q18. Which observation most likely indicates microbial contamination in a penicillin fermenter?

• Clear broth with increased penicillin yield
• Increased turbidity and decreased penicillin yield
• Stable pH and unchanged yield
• Improved pellet uniformity and higher kLa

Correct Answer: Increased turbidity and decreased penicillin yield

Q19. What is the specific purpose of adding phenylacetic acid to the fermentation medium?

• pH buffering
• Source of nitrogen
• Provide the benzyl side chain precursor for penicillin G
• Act as an antifoam

Correct Answer: Provide the benzyl side chain precursor for penicillin G

Q20. Which compound is the core intermediate used to synthesize many semisynthetic penicillins?

• Penicillin G
• Phenylacetic acid
• 6-Aminopenicillanic acid (6-APA)
• Cephalosporin C

Correct Answer: 6-Aminopenicillanic acid (6-APA)

Q21. Which type of bioreactor is most commonly employed for industrial penicillin production?

• Packed-bed reactor
• Stirred-tank bioreactor
• Photobioreactor
• Fixed-film reactor

Correct Answer: Stirred-tank bioreactor

Q22. Which method has historically been used to improve penicillin-producing strains?

• Switching to solid-state fermentation only
• Mutagenesis and selection
• Eliminating corn steep liquor
• Using UV light without selection

Correct Answer: Mutagenesis and selection

Q23. Which organic solvent is commonly used for liquid-liquid extraction of penicillin from aqueous broth?

• Water
• Ethanol
• Butyl acetate
• Acetone

Correct Answer: Butyl acetate

Q24. When during the growth cycle is penicillin production (secondary metabolism) typically highest?

• Lag phase
• Exponential (log) phase
• Stationary phase
• Decline (death) phase

Correct Answer: Stationary phase

Q25. What is the role of dissolved oxygen in penicillin biosynthesis?

• Oxygen is not required for biosynthesis
• Oxygen is essential for enzymatic steps in penicillin biosynthesis
• Oxygen acts only as an antifoam
• Excess oxygen inhibits production by directly degrading penicillin

Correct Answer: Oxygen is essential for enzymatic steps in penicillin biosynthesis

Q26. Which pH is typically maintained during the production phase for optimal penicillin yield?

• pH 3.0
• pH 4.0
• pH 6.5
• pH 8.5

Correct Answer: pH 6.5

Q27. What is the likely effect of adding a large amount of glucose late in the fermentation?

• Increase penicillin production due to extra energy
• Decrease penicillin production due to catabolite repression
• No effect on penicillin levels
• Immediate conversion of penicillin to 6-APA

Correct Answer: Decrease penicillin production due to catabolite repression

Q28. What is the usual method to sterilize fermentation medium at industrial scale?

• Autoclaving (steam sterilization)
• UV irradiation only
• Chemical sterilization without heat
• Dry heat at 180 °C

Correct Answer: Autoclaving (steam sterilization)

Q29. Which quality control test measures biological potency of penicillin batches?

• Mass spectrometry for impurity profiling
• Microbiological bioassay (agar diffusion)
• Viscosity measurement
• Microscopic pellet count

Correct Answer: Microbiological bioassay (agar diffusion)

Q30. What term describes the amount of penicillin produced per unit volume per unit time (e.g., g/L·h)?

• Titer
• Yield coefficient
• Productivity (volumetric productivity)
• Specific growth rate

Correct Answer: Productivity (volumetric productivity)

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