Isolation of a novel cold-adapted amylase-producing bacterium and study of its enzyme production conditions
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A novel cold-adapted amylase-producing bacterium was isolated from seawater collected from Gaogong island of Jiangsu Province, China. The isolate was identified based on its phenotypes, biochemical test, and 16 S rRNA gene sequence as Pseudoalteromonas arctica and named GS230. The optimal activity temperature of isolate GS230 amylase was 30°C, and the activity decreased dramatically at temperatures above 40°C. Compared with the amylase from mesophiles and thermophiles, the cold-adapted amylase showed higher enzyme activity at low temperature and a greater degree of heat sensitivity at temperatures higher than 40°C. Ca2+ showed a significant effect on maintaining the activity of the enzyme. The α-amylase could have important applications in the food industry. A number of factors affecting the production of the extracellular amylase were investigated. Soluble starch and beef extract were the most promising carbon and nitrogen sources, respectively. When the strain was cultured at 20°C, pH 8.0 for 24 h, the amylase activity peaked at 780.4 U/ml.
KeywordsScreening Identification Cold-adapted amylase Pseudoalteromonas arctica Production
This work was financially supported by National Natural Science Foundation of China (40746030), Natural Science Foundation of the Science and Technology Department of Jiangshu (BE200830094), Natural Science Foundation of the Science and Technology Department of Lianyungang City (CG0714), Natural Science Foundation of the Jiangsu Higher Education Institutions of China (08KJB550001).
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