Penicillin production with Penicillium chrysogenum is conducted under which oxygen regime?
-
AAerobic fermentation (oxygen supplied actively)
-
BStrict anaerobic fermentation (no oxygen)
-
CAerobic fermentation followed by anaerobic finishing
-
DAnaerobic fermentation followed by aerobic finishing
-
EMicroaerophilic static culture with no aeration control
Answer
Correct Answer: Aerobic fermentation (oxygen supplied actively)
Explanation
Introduction / Context:Penicillin biosynthesis is highly oxygen-dependent. Industrial fermenters supply substantial aeration and agitation to meet oxygen transfer requirements and maintain metabolic activity for high titers of penicillin G or V under fed-batch conditions.
Given Data / Assumptions:
- Organism is strictly aerobic for production.
- Viscous broths and pellet morphology can limit oxygen transfer.
Concept / Approach:Aeration and agitation are engineered to maintain dissolved oxygen above a minimum setpoint (often 20–40% of air saturation), avoiding oxygen limitation that depresses antibiotic formation. Consequently, aerobic fermentation is essential; anaerobic conditions would halt production and shift metabolism undesirably.
Step-by-Step Solution:
Recall Penicillium chrysogenum requires oxygen for both growth and penicillin formation.Identify the correct oxygen regime: aerobic.Select “Aerobic fermentation”.Verification / Alternative check:Standard penicillin plant designs feature spargers, high kLa, and antifoam systems to support sustained aeration.
Why Other Options Are Wrong:
- Anaerobic or two-step regimes are not used for penicillin formation.
- Microaerophilic static culture is inadequate for industrial titers.
Common Pitfalls:Underestimating the oxygen demand of high-cell-density fungal cultures producing secondary metabolites.
Final Answer:Aerobic fermentation (oxygen supplied actively)