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Abstract

A moderately halophilic g+, rod shaped, spore-forming isolated from saline soil from Karaj, Iran, produced extracellular amylase when cultivated aerobically in medium containing starch, peptone, beef extract and NaCl. The maximum amylase production was secreted in the presence of 15% (w/v) Na2SO4. The isolate was capable of producing amylase in the presence of NaCl 10% (w/v), NaCH3COO 15% (w/v), or KCl 5% (w/v), with the results NaCl>NaCH3COO> KCl. Amylase production was not detected when ammonium nitrate, potassium nitrate, sodium nitrate or sodium citrate were used, although bacterial growth occurred. Potential of different carbohydrates in the amylase production was in the order: dextrin > starch > maltose > lactose > sucrose > glucose. Various carbon sources induced enzyme production. 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 7.8 and 50°C respectively. The bacterium was g+, non–motile, oxidase ?, catalase +, aerobic Bacillus. Starch, casein, and gelatin were hydrolyzed. Nitrate and nitrite reduction were negative. The isolate grows well in media containing 0.5 to 24% (w/v) salt. Following the criteria of "Bergey’s Manual of Systematic Bacteriology", the isolate was identified as a Bacillus sp. strain MA. Further investigation is underway.

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