Production of amylase by newly isolated moderate halophile, Halobacillus sp strain MA-2

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 MA2 in medium containing starch, peptone, beef extract, and NaCl. The maximum amylase production was secreted in the presence of 15% (w/v) Na2SO4 (3.2 U ml(-1)). The isolate was capable of producing amylase in the presence of NaCl, NaCH3COOH, or KCl, with the results NaCl>NaCH3COOH>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 bad no significant enhancement on amylase production (p < 0.05). The pH, temperature, and aeration optima for enzyme production were 7.8, 30 degreesC, and 200 rpm, respectively, while the optimum pH and temperature for enzyme activity was 7.5-8.5 and 50 degreesC, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.