Bioprocessing of penicillin MCQs With Answer

Introduction: Bioprocessing of Penicillin MCQs With Answer

This collection of multiple-choice questions is designed for M.Pharm students studying Bioprocess Engineering and Technology. The quiz focuses on the microbiology, fermentation strategies, biochemistry of penicillin biosynthesis, upstream process control (oxygen transfer, nutrient limitation, morphology), downstream recovery (clarification, extraction, salt formation) and analytical & regulatory considerations. Questions emphasize mechanistic understanding, common industrial practices (fed‑batch strategies, precursor feeding) and critical process parameters that influence yield and quality. Use these MCQs for exam preparation, classroom revision or self-assessment to build a deeper, application-oriented grasp of penicillin bioprocessing beyond superficial facts.

Q1. Which organism is classically used for industrial penicillin production?

• Penicillium chrysogenum
• Aspergillus niger
• Streptomyces griseus
• Escherichia coli

Correct Answer: Penicillium chrysogenum

Q2. Penicillin is best classified as which type of microbial metabolite?

• Primary metabolite
• Secondary metabolite
• Structural metabolite
• Energy metabolite

Correct Answer: Secondary metabolite

Q3. Which precursor is commonly supplied to direct biosynthesis toward benzylpenicillin (penicillin G)?

• Aminoadipic acid
• Phenylacetic acid
• Benzoic acid
• Acetic acid

Correct Answer: Phenylacetic acid

Q4. Which pair of enzymes is directly involved in the formation of the penicillin nucleus?

• ACV synthetase and isopenicillin N synthase (IPNS)
• Penicillin acylase and beta‑lactamase
• Polyketide synthase and nonribosomal peptide synthetase
• Transaminase and dehydrogenase

Correct Answer: ACV synthetase and isopenicillin N synthase (IPNS)

Q5. Which fermentation mode is most commonly employed industrially to maximize penicillin yields while controlling precursor levels?

• Continuous culture (chemostat)
• Batch culture without feeding
• Fed‑batch culture with precursor feeding
• Semi‑continuous culture with periodic harvests

Correct Answer: Fed‑batch culture with precursor feeding

Q6. Which nitrogen source is classically used in penicillin fermentation media to support high productivity?

• Corn steep liquor
• Sodium nitrate only
• Ammonium chloride only
• Yeast extract-free media

Correct Answer: Corn steep liquor

Q7. What fungal morphology is generally preferred in industrial penicillin fermentations to reduce broth viscosity and improve mass transfer?

• Highly branched dispersed mycelium
• Heterogeneous clumps
• Compact pellet form
• Single spores predominance

Correct Answer: Compact pellet form

Q8. Which process parameter is most critical for achieving high penicillin productivity due to its effect on oxygen-dependent biosynthetic enzymes?

• Dissolved oxygen / oxygen transfer rate (kLa)
• Broth color
• Incubation time only
• Magnetic stirring speed in shaker flasks

Correct Answer: Dissolved oxygen / oxygen transfer rate (kLa)

Q9. During the production phase of penicillin fermentation, the pH is typically maintained around which range?

• pH 3.0–4.0
• pH 6.0–6.5
• pH 8.5–9.0
• pH 10.0–11.0

Correct Answer: pH 6.0–6.5

Q10. Excessive addition of silicone antifoam during penicillin fermentation most directly causes which issue?

• Increased product titer by stimulating biosynthesis
• Decreased oxygen transfer and lower productivity
• Complete sterilization of the culture
• Precipitation of penicillin

Correct Answer: Decreased oxygen transfer and lower productivity

Q11. What is the usual primary clarification step to remove fungal biomass before downstream extraction of penicillin?

• High‑speed centrifugation or continuous centrifugation
• Membrane ultrafiltration as the only step
• Lyophilization of whole broth
• Direct crystallization from whole broth

Correct Answer: High‑speed centrifugation or continuous centrifugation

Q12. Which downstream unit operation is commonly used to recover penicillin from clarified broth after acidification?

• Liquid‑liquid solvent extraction
• Gas chromatography
• Direct lyophilization
• Gel electrophoresis

Correct Answer: Liquid‑liquid solvent extraction

Q13. Conversion of benzylpenicillin to its commonly used injectable form is typically performed by forming which salt?

• Sodium salt
• Calcium salt
• Magnesium salt
• Ammonium salt only

Correct Answer: Sodium salt

Q14. For precise and routine quantification of penicillin concentration in process samples, which analytical technique is preferred in industry?

• High‑performance liquid chromatography (HPLC)
• Simple colorimetric paper test
• Gram staining
• Thin‑layer chromatography only

Correct Answer: High‑performance liquid chromatography (HPLC)

Q15. A common metabolic factor that represses penicillin biosynthesis when present in excess is:

• High dissolved oxygen
• High glucose concentration (catabolite repression)
• Low temperature
• Presence of phenylacetic acid precursor

Correct Answer: High glucose concentration (catabolite repression)

Q16. Production of penicillin is typically induced when which nutrient becomes limiting, shifting the culture into the idiophase?

• Nitrogen limitation
• Excess carbon source
• Excess oxygen
• High phosphate concentration

Correct Answer: Nitrogen limitation

Q17. The role of phenylacetic acid in penicillin G biosynthesis is best described as:

• A carbon source for growth only
• The specific side‑chain (acyl) precursor for benzylpenicillin
• An enzyme inhibitor that halts production
• The primary nitrogen source

Correct Answer: The specific side‑chain (acyl) precursor for benzylpenicillin

Q18. Historically, industrial strain improvement of penicillin producers relied mainly on which approach?

• Directed recombinant gene replacement exclusively
• Random classical mutagenesis and selection
• CRISPR gene drives in production fermenters
• Natural outgrowth without intervention

Correct Answer: Random classical mutagenesis and selection

Q19. Which process modification is most likely to increase final penicillin titre during a production run?

• Continuous high glucose feed throughout the run
• Fed‑batch feeding of the acyl side‑chain precursor at controlled rates
• Complete removal of oxygen during production phase
• Rapid heating to 40–45 °C in mid‑run

Correct Answer: Fed‑batch feeding of the acyl side‑chain precursor at controlled rates

Q20. At which fermentation phase is penicillin concentration typically maximal?

• Exponential growth (trophophase)
• Late stationary / idiophase (production phase)
• Initial lag phase
• Immediately after inoculation

Correct Answer: Late stationary / idiophase (production phase)

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