18S rDNA和ITS相结合鉴定一株盐生海芦笋内生真菌的研究

Identification of a Halophilic Endophytic Fungus Isolated from Salicornia bigelovii

对分离自盐生海芦笋的一株代号为Salicorn 8的真菌进行鉴定,提取基因组DNA后分别PCR扩增18S rDNA和ITS区域,基因测序并进行同源性分析,构建ITS基因系统发育树,结合形态学分析,将该菌鉴定为木贼镰刀菌(Fusarium equiseti)。

In the current study,high-xylanase-producing strain was screened from different soil samples by transparent circle method,using xylan as the only carbon source in medium.The cultural condition for xylanase production by strain L10608 was optimized and the hydrolysis property of the enzyme was further investigated.The results indicated that the optimum fermentation medium contained a carbon source of water-insoluble xylan（80 mesh） of 25 g/L,compound nitrogen source of soya peptone of 25 g/L and yeast extract of 5 g/L,initial pH 6.0,cultural temperature 40 ℃,rotational speed of 200 r/min,surfactant polysorbate 80 of 4 g/L.Under the optimized condition,the enzyme activity reached 1074.8 U/mL.The xylanase utilized all birch wood xylan,beech wood xylan and oat xylan as the substrate,exhibiting that xylanase produced by L10608 was endo-xylanase with xylobiose and xylotriose as the major hydrates.These results showed that strain L10608 could hopefully be used for industrial production of functional xyloolygosaccharides.