This research was conducted to optimise and stabilise cellulase and xylanase production by
Beauveria bassiana B14532. Optimisation for pH (4.0, 6.5 and 9.0) and temperature (30, 55 and
80oC) was attained by a response surface methodology (RSM) model to fit the data using central
composite design (CCD). Results indicated that B. bassiana B14532 recorded cellulase and xylanase
activity at 3.59 UmL-1 (144h) and 39 UmL-1 (120h) respectively. Optimum pH and temperature
which produced the highest cellulase (3.89 UmL-1) were 6.5 and 80oC respectively while highest
xylanase (41.01 UmL-1) was obtained from optimum pH 6.5 and temperature 55oC. Coefficients
of determination R2 were 0.93 (cellulase activities) and 0.98 (xylanase activities). Stability of the
cellulase and xylanase enzymes was investigated at the optimised pH values and temperatures for
120 min. Results showed that both enzymes decreased as reaction time increased by every 10 min.
Cellulase retained 88, 80, 74, 66 and 55% of its activity at pH 6.5, 80oC post incubation for 50 min,
while xylanase retained higher enzyme values at 93, 91, 83, 70, 65, 61 and 50% of its activity at pH
6.5, 55oC post incubation for 70 min.