一株高产木聚糖酶菌株的筛选鉴定及酶学特性研究

摘要

The strain RX-9 producing high xylanase was screened through preliminary screening and shake flask,based on enriched medium with xylan as the sole carbon source.The strain RX-9 had more than 99％ homology to Enterobacter,and was ascribed to Enterobacter sp.named as Enterbacter RX-9 by the colony morphology,physiological and biochemical analysis of experiment and genetic analysis of 16s rRNA sequence.The enzymatic properties of xylanase produced by the strain RX-9 was studied,and found that the enzyme activity was still 2310.03 U/mL kept at 100 ℃ for 30 min,and The xylanase activity was above 3200 U/mL when pH was 7.5～9.5.The results showed that the xylanase had good thermal stability and pH stability.%以木聚糖为唯一碳源,在富集培养基的基础上,通过初筛和摇瓶复筛,筛选到一株高产木聚糖酶的菌株RX-9,对菌株RX-9进行菌落形态、生理生化实验及16S rRNA序列遗传分析,该菌株的序列与Enterbacter(肠杆菌属)的多株菌具有99％以上的同源性,将该菌株归属为肠杆菌属(Enterbacter),命名为Enterbacter RX-9.对菌株所产木聚糖酶的酶学特性进行研究,发现该菌株所产的木聚糖酶在100℃下保温30 min,其酶活力仍达到2310.03 U/mL;当pH在7.5 ～9.5之间,木聚糖酶的活性基本稳定在3200 U/mL以上,表明该酶具有较好的热稳定性和pH稳定性.