一株海藻多糖降解菌的分离与鉴定

Isolation and identification of a seaweed polysaccharide degrading bacteria strain

【目的】从腐烂的褐藻中筛选一株海藻多糖降解菌,编号L206,分析其对不同多糖的降解能力。【方法】通过形态观察、生化单因子试验及16S r RNA基因鉴定细菌,DNS法测定海藻多糖降解酶活性等。【结果】海洋细菌L206,革兰氏阴性短杆菌,生长对数期为3-21 h,适宜生长的Na Cl质量浓度为0-3%(质量体积比);通过16S r RNA基因鉴定为白色噬琼胶菌(Agarivorans albus);L206被海带粉诱导至72 h时,综合复合酶活力达到最大,其中淀粉酶活力最高(28.17 U/m L),木聚糖酶次之(23.83 U/m L)。【结论】白色噬琼胶菌L206是一株多能型多糖降解菌,对褐藻多糖有特殊的降解能力,具有潜在开发价值。

[Objective] A bacterial strain,L206,which could degrade seaweed polysaccharides was isolated from the rotten brown algae.This research aims to analyze its ability to degrade different polysaccharides of seaweed.[Methods] The morphologic,biochemical and physiological characteristics and 16 S r RNA gene were analyzed to identify the taxonomic position of strain L206.Then the activity of seaweed polysaccharide degrading enzyme was measured by DNS.[Results] The bacterial strain was a Gram-negative short bacillus.Its logarithmic growth phase was 3-21 h,with Na Cl concentration range from 0 to 3%（W/V） for suitable growth.Phylogenetic analysis based on 16 S r RNA gene sequence comparisons indicated that the strain L206 was Agarivorans albus.The comprehensive enzyme activity reached maximum level after strain L206 was induced for 72 h by the powder of Laminaria japonica,amylase present the highest enzymatic activity（28.17 U/m L）,and followed by xylanase（23.83 U/m L）.[Conclusion] As a multi-functional polysaccharide-degrading bacterium,Agarivorans albus L206 shows a special ability to degrading brown algae polysaccharide and has a great development potential.