| Title | Overexpression and characterization of a novel cold-adapted and salt-tolerant GH1 β-glucosidase from the marine bacterium Alteromonas sp. L82 |
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| Author | Jingjing Sun1,2, Wei Wang1,2, Congyu Yao1,2,3, Fangqun Dai1,2, Xiangjie Zhu1,2,3, Junzhong Liu1,2, and Jianhua Hao1,2,4* |
| Address | 1Key Laboratory of Sustainable Development of Polar Fishery, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences Qingdao 266071, P. R. China, 2Laboratory for Marine Drugs and Bioproducts, Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology Qingdao 266071, P. R. China, 3Shanghai Ocean University, Shanghai 201306, P. R. China, 4Jiangsu Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resource, Lianyungang 222005, P. R. China |
| Bibliography | Journal of Microbiology, 56(9),656–664, 2018, |
| DOI | 10.1007/s12275-018-8018-2 |
| Key Words | β-glucosidase, marine, Alteromonas, cold adaptation, salt tolerance |
| Abstract | A novel gene (bgl) encoding a cold-adapted β-glucosidase was cloned from the marine bacterium Alteromonas sp. L82. Based on sequence analysis and its putative catalytic conserved region, Bgl belonged to the glycoside hydrolase family 1. Bgl was overexpressed in E. coli and purified by Ni2+ affinity chromatography. The purified recombinant β- glucosidase showed maximum activity at temperatures between 25°C to 45°C and over the pH range 6 to 8. The enzyme lost activity quickly after incubation at 40°C. Therefore, recombinant β-glucosidase appears to be a cold-adapted enzyme. The addition of reducing agent doubled its activity and 2 M NaCl did not influence its activity. Recombinant β-glucosidase was also tolerant of 700 mM glucose and some organic solvents. Bgl had a Km of 0.55 mM, a Vmax of 83.6 U/mg, a kcat of 74.3 s-1 and kcat/Km of 135.1 at 40°C, pH 7 with 4-nitrophenyl-β-D-glucopyranoside as a substrate. These properties indicate Bgl may be an interesting candidate for biotechnological and industrial applications. |