Penicillin production with Penicillium chrysogenum is conducted under which oxygen regime?

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:

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)