Interpreting microbial growth and metabolite curves in Penicillium culture

Steps:

• Identify curve X as the decreasing line, representing substrate depletion.
• Identify curve Y as the steadily increasing line, representing product accumulation.
• Identify curve Z as the sigmoidal growth curve, representing biomass increase.
• Match to biological roles: sugar depletes, penicillin forms, fungus grows.

Why C is correct:

• In fungal fermentation, substrate (sugar) decreases (X) as biomass (Penicillium) grows (Z) and product (penicillin) accumulates (Y), per microbial kinetics.

Why the others are wrong:

• A: Misassigns decreasing X to product, ignoring penicillin's accumulation.
• B: Confuses biomass Y with product, as fungus growth plateaus differently.
• D: Swaps Y and Z, mismatching product rise with fungal growth pattern.

Final answer: C