Production and biochemical characterization of an alpha-amylase from the moderate halophile Halomonas meridiana

Extracellular amylase production by the moderate halophile Halomonas meridiana was optimized and the enzyme was characterized biochemically. The highest amylase production was achieved by growing H. meridiana cultures in media with 5% salts and starch, in the absence of glucose until the end of the exponential phase. The amylase exhibited maximal activity at pH 7.0, being relatively stable in alkaline conditions. Optimal temperature and salinity for activity were 37 degrees C and 10% NaCl, respectively. Moreover, activity at salinity as high as 30% salts was detected. Maltose and maltotriose were the main end products of starch hydrolysis, indicating an alpha-amylase activity.