Penicillin fermentation — events in the first (growth) phase of Penicillium chrysogenum During the initial growth phase of Penicillium chrysogenum in penicillin fermentation, which combination of observations is characteristic?

Introduction / Context:
Industrial penicillin production follows a multi-phase fermentation profile. Understanding physiological events in each phase helps optimize aeration, feeding, and timing for maximal antibiotic titers.

Given Data / Assumptions:

• Phase examined: the first (trophophase) of P. chrysogenum growth.
• Medium: complex, often containing corn steep liquor with lactic acid and nitrogenous sources.
• Process: aerobic, with controlled pH and aeration.

Concept / Approach:

In the initial phase, rapid mycelial growth predominates. Organic acids present (e.g., lactic acid) are assimilated, which can influence pH trends. Nitrogen metabolism and deamination can release ammonia, affecting pH upward over time. These biochemical events set the stage for the subsequent production (idiophase), where penicillin biosynthesis is maximized.

Step-by-Step Solution:

Verification / Alternative check:

Fermentation profiles documented in classic penicillin literature describe an early growth-focused phase with organic acid uptake and measurable ammonia in broth, followed by a production phase where secondary metabolism (penicillin) increases.

Why Other Options Are Wrong:

Option e is incorrect because lactic acid is typically consumed from the medium; the organism does not produce lactic acid in this aerobic filamentous fungal process.

Common Pitfalls:

Assuming antibiotic synthesis peaks during the first phase; in fact, maximum penicillin formation aligns more with the second (production) phase once biomass has been established.

Final Answer:

All of the above