Question

In the fed-batch method the critical elements of the nutrient solution are added in which amount of concentrations at the beginning of the fermentation?

(a) Small

(b) Large

(c) Very large

(d) Little

The question was posed to me in unit test.

Origin of the question is Fed Batch Culture topic in chapter Microbial Growth Kinetics of Bioprocess Engineering

Answer 1

Right answer is (a) Small

To explain I would say: Fed-batch cultivation can provide the solution to substrate inhibition problem by slow feeding of nutrients to the bioreactor; however it can still not address the severe inhibition problem due to accumulating high product concentrations. The optimal design of fed-batch cultivation has to take in to account several factors in to consideration for example time to start the fresh nutrient feed (in the end or when the culture is exponentially growing) what should be the substrate concentration in the feed and its rate of addition and when to finish the nutrient feeding so that the highest concentration of product is produced and no unconverted substrate when the reactor is full.