Abstract
Production of extracellular amylase was demonstrated under stress conditions of high temperature and high salinity in aerobically cultivated culture of a newly isolated moderately halophilic bacterium of spore-forming Halobacillus sp. strain MA-2 in medium containing starch, peptone, beef extract, and NaCl. The maximum amylase production was secreted in the presence of 15% (w/v) Na 2SO 4 (3.2 U ml −1). The isolate was capable of producing amylase in the presence of NaCl, NaCH 3COOH, or KCl, with the results NaCl>NaCH 3COOH>KCl. Maximum amylase activity was exhibited in the medium containing 5% (w/v) NaCl (2.4 U ml −1). Various carbon sources induced enzyme production. The potential of different carbohydrates in the amylase production was in the order: dextrin>starch>maltose>lactose>glucose>sucrose. In the presence of sodium arsenate (100 mM), maximum production of the enzyme was observed at 3.0 U ml −1. Copper sulfate (0.1 mM) decreased the amylase production considerately, while lead nitrate had no significant enhancement on amylase production ( p<0.05). The pH, temperature, and aeration optima for enzyme production were 7.8, 30 °C, and 200 rpm, respectively, while the optimum pH and temperature for enzyme activity was 7.5–8.5 and 50 °C, respectively.
Published Version
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