Question

under continuous culture which of the following condition is applicable?

(a) μmax < D

(b) μmax > D

(c) μmax = D

(d) μmax = 0

This question was addressed to me by my school principal while I was bunking the class.

The doubt is from Continuous Culture topic in section Microbial Growth Kinetics of Bioprocess Engineering

Answer 1

Right choice is (b) μmax > D

For explanation: The net change in cell concentration over a time period may be expressed as:

dx/dt = growth – output

dx/dt = μx – Dx

Under steady-state conditions, the cell concentration remains constant, thus dx/dt = 0 and:

μx = Dx

μ = D

Under steady-state conditions the specific growth rate is controlled by the dilution rate. Under batch culture conditions an organism will grow at its maximum specific growth rate and, therefore, it is obvious that a continuous culture may be operated only at dilution rates below the maximum specific growth rate. Thus, within certain limits the dilution rate may be used to control the growth rate of the culture.