右旋糖酐酶产生菌的筛选及分类鉴定

Screening and identification of a dextranase yield fungus

从土壤中筛选出一株右旋糖酐酶产生菌(D5),可水解右旋糖酐产生单一产物——异麦芽三糖,为外切型异麦芽三糖水解酶产生菌。经分生孢子、分生孢子梗、菌落形态,色素颜色等形态学观察,分析其为黄绿青霉。对菌株的ITS rDNA序列进行克隆测序,与GenBank中已知菌的ITS rDNA比对,用Neighbor-joining方法构建聚类分析树状图,并用Bootstrap法对其评估,结果表明ITS序列的分子鉴定支持了基于形态特征的鉴定结果。该菌株的ITS与Penicillium daleae,Penicillium janthinellum菌株的ITS rDNA序列同源性最高。

An exo-isomaltotriodextranase yield strain was screened.It showed higher activity against alpha-（1,6） glucan and released isomaltotriose as main products from dextran 70000.After observation of morphology and color of the colony,morphology of conidiospores and conidiophores,the strain was preliminarily identified as Penicillium citreoviride.The ITS rDNA was cloned and sequenced,and then was compared with those available in the GenBank databases.The phylogenetic trees were derived with neighbor joining and analyzed with Bootstrapping.The results showed that the ITS sequence analysis supported the identification based on morphological characteristics of D5.D5 strain is close consanguinity to Penicillium daleae and Penicillium janthinellum.