Production and optimization of α-amylase from thermo-halophilic bacteria isolated from different local marine environments

Abstract

Amylases are among the most important enzymes which are of great significance for biotechnology and have almost completely replaced chemical hydrolysis of starch in the starch processing industry. The present study was concerned with the production and optimization of extracellular α-amylase from Bacillus sp. NRC22017. The effect of various fermentation conditions on α-amylase production through shake-flask culture was investigated. Bacterial strain produces α-amylase was isolated from water in Wadi El-Natron. Based on microbiological, biochemical tests, and 16S rRNA gene sequences, the isolate was identified as Bacillus sp. NRC22017 and was later used for further studies. Maximum yield of α-amylase is 15.15 ± 0.47 U/ml from Bacillus sp. NRC22017; this strain is characterized with high temperature and high salinity in cultivated culture, and achieved maximum yield of α-amylase at pH 6.0 with inoculum size of 500 μl at 45 °C and aerobically incubation period of 72 h. The optimum volume of the fermentation medium was found to be 20 ml in 100 ml Erlenmeyer flask; the best starch and meat extract plus peptone concentration that provided the highest enzyme production from Bacillus sp. NRC22017 were found to be 2% and 1.05% (w/v) respectively. Enzyme production was higher after optimizing the production conditions as compared to the basal medium.