Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8326615 | International Journal of Biological Macromolecules | 2018 | 7 Pages |
Abstract
An agar-degrading bacterium, strain BN3, was isolated from a coastal soil sample collected in Taiwan Strait, China and identified to be a novel species of the genus Microbulbifer. The gene (N3-1) encoding for a novel β-agarase from the isolate was cloned and sequenced. It encoded a mature protein with 274 amino acids and a calculated molecular mass of 34.3â¯kDa. The deduced amino acid sequence manifested sequence similarity (61-84% identity) to characterized β-agarases in the glycoside hydrolase family 16. The recombinant agarase was hyper-produced extracellularly using Pichia pastoris as the host. After induction in a shake flask for 96â¯h, the yield of recombinant N3-1 protein reached 0.406â¯mg/mL, and the enzyme activity attained 502.1â¯U/mL. The enzyme purified by ion exchange chromatography displayed a specific activity of 6447â¯U/mg at pHâ¯6.0 and 50â¯Â°C. The optimal pH and temperature for agarase activity were approximately 6 and 50â¯Â°C, respectively. The pattern of agarose hydrolysis showed that the enzyme was an endo-type β-agarase, capable of hydrolyzing agarose and Gracilaria lemaneiformis, with neoagarobiose and neoagarotetraose as the final main products.
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Biochemistry
Authors
Ren-Kuan Li, Zeng Chen, Xi-Juan Ying, Tzi Bun Ng, Xiu-Yun Ye,