Optimisation of fungal glucoamylase production by Response Surface Methodology and characterisation of the purified enzyme

Abstract

A statistical approach was made for the production of glucoamylase by Aspergillus niger using wheat bran and green gram as fermentation medium. Box-Behnken design used to analyse the simultaneous impact of the substrate, hydration, inoculum volume, fermentation time and temperature, using a second-order polynomial. The experimental results were in good agreement with the proposed regression model with R2 = 0.9322 (p<0.05). The maximum yield (313 U/gds against the predicted value of 306 U/gds) was obtained using 12 gm substrate, 55% moisture, 1 gm sucrose and 0.05 gm tryptone. The purification and characterisation of the enzyme were also studied. Optimum thermal and pH stability was 60 °C and 5 respectively.