Endoglucanase Production by Humicola insolens: Effect of Physiochemical Factors on Growth Kinetics and Thermodynamics

The effect of physiochemical factors on the productivity of endoglucanases by a local thermophillic fungal strain of Humicola insolens was investigated. Carboxymethylcellulase (CMCase) was produced under submerged fermentation and the effects of inoculum size temperature pH and substrate concentration on the growth kinetic parameters ( td Yp/x qp max qp(max) were determined. Optimal conditions for CMCase production were: inoculum density= 8% v/v (12.41mg cells mL-1) substrate (CMC) = 5% (w/v) pH = 5.0 temp = 45C. The extracellular CMCase and protein production under optimized conditions was 2.0 UmL-1 and 0.129 mg mL-1 respectively. Growth kinetic parameters were as follows: specific growth rate () = 0.046; td = 15.02 h; Yp/x = 0.0139 max = 0.0458 h-1 qp(max)= 0.0011 U h-1 mg-1 cell mass. The activation energy for the enzyme production Ea(p) was 108.69 kJ mol-1. Thermodynamic parameters i.e. 6H p 6G p and 6S p were 106.047 KJ mol-1 117.589 KJ mol-1 and -36.29 J mol-1K-1 respectively. The results are novel because it is the first report on kinetics and thermodynamics of CMCase production by H. insolens. Copyright 2014 Friends Science Publishers