Question

Growth curve was studied using bacteria to produce microbial protein.

Normally bacteria require media components for its growth. One of the major component is valine. 500 kg of valine was added to fermentation medium in a bioreactor to perform growth studies. The concentration of cells in 500 L of

3

medium was found to be 500 kg/m . Calculate the percentage of nitrogen in

bacteria.

Answer 1

500 Kg of valine was given to produce 500 Kg/m3 of bacteria

500 L converted to m3 unit

500 x 1000 cm3= 500,000 cm3= 500,000 (0.01)3 m3= 500,000 x 10-6m3   = 0.5 m3

500 kg of microbe is produced in 1 m3 then in 500 L or 0.5 m3 it will be half 250 kg

250 kg organism is produced from 500 Kg valine

50 % is the yield with respect to valine

as whole organism is produced from valine (molecular weight 121 ) media so Nitrogen (atomic weight 14) contributes 11% of valine similarly nitrogen is 11% with respect to valine in organism

with respect to total valine it is half the conc i.e. 5.5% as half mass valine is coverted to organism mass