Optimization of synergistic parameters for thermostable cellulase activity of Aspergillus heteromorphus using response surface methodology

This study was undertaken to find out the optimum reaction conditions, i.e. pH, temperature, enzyme and substrate concentration for the thermostable cellulase enzyme activity of Aspergillus heteromorphus using response surface methodology (RSM). Estimated optimum conditions for cellulase enzyme were found as: pH 4.8, temperature 60 °C, crude enzyme/substrate concentration ratio was 4:6. The maximum enzymatic activity calculated was observed 13.05 U/ml against the predicted value 11.26 U/ml. Cellulase system of A. heteromorphus is thermostable retaining 60.0% of residual activity after 1 h of pre-incubation at 90 °C when assay is carried out at same temperature. Value of correlation coefficient (R2 0.9977) and significant value for model p < 0.0001 indicated validity of model fitness and adequate for optimization.