Thermostable alpha-amylase production by an extreme thermophile Bacillus thermooleovorans.

Abstract

alpha-Amylase production by a newly isolated thermophile, Bacillus thermooleovorans, was studied under different cultivation conditions. The influence of various carbon and nitrogen sources on alpha-amylase production was quantified in batch fermentation in shake flasks. Starch and tryptone were observed to be the ideal carbon and nitrogen sources, respectively. Cultivation of the organism in a chemically defined medium consisting of glucose, riboflavin, cysteine, MgSO4, K2HPO4 and NaCl led to a near twofold increase in the production of alpha-amylase in comparison with that in the complex medium. The increase in enzyme production was achieved using vitamins and amino acids. When the organism was grown in a laboratory fermenter in the optimized complex medium, the noticeable effects were the near abolition of the lag phase, a 2.2-fold increase in enzyme production and a reduction in optimal production time from 12 to 4-5 h. Enhancement of amylase production was achieved under various cultivation conditions. Bacillus thermooleovorans produces a calcium-independent and thermostable amylase which can find use in starch saccharification.