Question

Tetrahymena thermophila protozoa have a minimum doubling time of 6.5 hours when grown using bacteria as the limiting substrate. The yield of protozoal biomass is 0.33 g per g of bacteria and the substrate constant is 12 mg/ L. The protozoa are cultured at steady state in a chemostat using a feed stream containing 10 g 1 of nonviable bacteria. What is the maximum dilution rate for operation of the chemostat?

Answer 1

Doubling time is given as ,

T_d= 6.5 , We know that

Dilution rate= $\frac{F}{V}$ , here F=Volumetric flow rate, V= Volume

and under case of limiting substrate

$\mu_{max}= \frac{0.693}{T_d}$

And in case of limiting substrate, $\mu_{max}=D$ here, D= Dilution rate

so,

$D=\frac{0.693}{T_d}$

$D=\frac{0.693}{6.5}$

D= 0.1066 $hr^{-1}$ , This is dilution rate