Optimization of the fermentation conditions and partial characterization for acido-thermophilic α-amylase from Aspergillus niger NCIM 548

摘要

A high performance thermostable a-amylase at low pH values has been synthesized. Sugarcane bagasse was hydrolyzed in a dilute acid solution and utilized as carbon source for the growth of Aspergillus niger strain NCIM 548. Glucose, xylose and arabinose with the ratio of 1.0 : 0.9 :0.3 (w/w/w) were detected in the hydrolyzate by HPLC analysis. Optimization of the fermentation conditions for α-amylase production was performed by varying four influential parameters such as Sugarcane bagasse hydrolyzate (SBH), NH_4Cl, pH and incubation time using a central composite design (CCD) under response surface methodology (RSM). The optimμMvalues of SBH, NH4Cl, pH and incubation time were 20.49, 2.34 g/l, 5.65 and 76.67 h, respectively. The acido-thermophilic enzyme showed maximμMstability at 70℃ and pH value of 4. The rate constant, K_m and maximμMreaction rate, V_(max) were 18.79 g/l and 15.85 g/l·min, respectively.