Enzyme salting-out. The solubility of cellulase enzyme in a buffered extract of Trichoderma viride cells is determined in the laboratory as a function of ammonium sulfate concentration. At (NH4)2SO4 concentrations of 1,8, 2,2, and 2,5 M, the solubilities are 44, 0,58, and 0,07 mg L, respectively. T. viride cells produced by fermentation are homogenised to generate 800 litres of buffered extract containing 25 mg L1 of soluble cellulase. Cellulase is precipitated by adding (NH4)2SO4 to the extract to give a concentration of 2,0 M and a final solution volume of 930 L.

a. Estimate the mass of the enzyme recovered.

b. What is the yield or percentage recovery of cellulase in this precipitation process?

c. The residual cellulase in solution is treated for further precipitation. Assuming negligible volume change for the second increment in salt content, estimate the concentration of (NH4)2SO4 required to recover 90% of the residual cellulase.