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

A high performance thermostable α-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), NH₄Cl, pH and incubation time using a central composite design (CCD) under response surface methodology (RSM). The optimum values 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 maximum stability at 70°C and pH value of 4. The rate constant, K_m and maximum reaction rate, V_max were 18. 79 g/l and 15. 85 g/l·min, respectively.