Question

Fed-batch fermentation involves

• A. Continuous removal of culture
• B. No substrate addition
• C. Intermittent addition of substrate
• D. Only gas exchange

Hint:

Remember the three fermentation modes: \[ \boxed{\text{Batch}=\text{No feeding}} \] \[ \boxed{\text{Fed-Batch}=\text{Controlled substrate addition}} \] \[ \boxed{\text{Continuous}=\text{Continuous feeding and culture removal}} \] Fed-batch fermentation is widely used in industrial production of antibiotics, enzymes, and recombinant proteins.

Answer 1

The Correct Option is C

Concept: Fed-batch fermentation is a modified batch fermentation technique in which fresh nutrients are added to the bioreactor during cultivation without removing the culture medium. This allows better control of nutrient concentration, prevents substrate inhibition, and increases product yield.

Step 1: Understand fed-batch fermentation.
Initially, microorganisms grow in a limited amount of medium. As nutrients become depleted, fresh substrate is supplied gradually. \[ \boxed{\text{Batch Culture} +\text{Controlled Feeding} = \text{Fed-Batch Fermentation}} \]

Step 2: Advantages of fed-batch fermentation.
Fed-batch systems:
• Prevent substrate inhibition.
• Extend the exponential growth phase.
• Increase biomass and product yield.
• Improve process control.

Step 3: Eliminate incorrect options.

• Continuous removal of culture occurs in continuous fermentation.
• Batch fermentation involves no nutrient addition.
• Gas exchange alone does not define fed-batch operation.
• Fed-batch specifically involves intermittent or controlled substrate addition. Final Answer: \[ \boxed{Option (C) is correct \]