Optimization of the thermostable alkaline and Ca-dependent α-amylase production from Bacillus paralicheniformis by statistical modeling

Abstract

A novel amylolytic enzyme producing thermoalkaliphilic bacterium, the source of industrially used enzymes was isolated. Isolated strain was identified by morphological, physio-biochemical tests and the 16S rRNA gene sequence analysis. The optimal conditions of enzyme activity were determined. For higher α-amylase production, the variables such as yeast extract, starch, CaCl2, (NH4)2SO4, NaCl and MgSO4 in the α-amylase production medium, the temperature and pH were screened by Plackett–Burman design and optimised using response surface methodology (RSM). The optimal conditions were found to be 0.15 g/L for starch, 0.15 mg/L for CaCl2 and 60 °C for temperature. By using RSM model, amylase production increase was achieved sevenfold. It is showed that this method can be utilised to optimize α-amylase production in athermophilic bacteria such as Bacillus paralicheniformis. Keywords: α-amylase; Bacillus paralicheniformis; optimization; response surface methodology.