一株产褐藻酸多糖的海洋假单胞细菌Pseudomonas sp. QDA的筛选和鉴定

Screening of an Alginate-Producing Marine Bacterium Pseudomonas sp. Strain QDA and its Characterization

根据已获褐藻酸多糖生物合成基因簇中褐藻胶裂解酶基因 (alg L )的序列设计特异性引物 ,利用 PCR技术从海洋微生物中筛选到 1株能够分泌胞外多糖的细菌。采用形态学观察和 1 6Sr D-NA序列分析鉴定该菌株 ,结果为假单胞属细菌 ,命名为 Pseudomonassp.QDA;系统发育树显示该菌株与 P.putida亲缘关系最近。菌株产生的胞外多糖可被褐藻胶裂解酶 (Alg L)降解 ,并在紫外 2 34nm处检测到特征性吸收 ,初步证明含有褐藻酸多糖。

Based on the DNA sequence of a novel alginate lyase gene (algL) that was cloned from a marine environmental DNA library, specific primer pairs were designed and used in PCR screening of an alginate-producing marine bacterium. With the method of phenotype observation and sequence analysis of the 16S rDNA, a marine bacterium was identified as some Pseudomonas that was most closely related to P.putida in the phylogenetic tree. The deacetylated exocellular polysaccharides could be degraded by a defined alginate lyase (AlgL) and the scanning graph of the digested mixture showed a characteristic absorption at 234nm, which suggested the existence of alginate.