降解纤维素嗜热菌的分离及纤维素酶性质分析

Isolation of cellulose-degradation thermophilic bacteria and character of cellulase

从福州永泰温泉分离到1株降解纤维素嗜热菌,通过形态特征和16S rDNA序列鉴定,将其命名为地芽孢杆菌(Geobacillussp.)TC-S8.采用3,5-二硝基水杨酸显色法(DNS法)对菌株TC-S8产胞外纤维素酶的发酵条件及酶性质进行研究.在培养基的初始pH为6.5,温度为60℃,装液量20%,接种量2%,摇床转速为120 r.min-1的条件下培养36 h,菌株TC-S8产酶量达到最大(229 mU.mL-1).其分泌的纤维素酶最适作用温度为60-70℃,最适pH为7.0.纤维素酶降解产物主要为葡萄糖,并有少量纤维二糖.

A cellulose-degradation thermophilic bacteria was isolated from hotsprings of Yongtai County in Fuzhou,which was named as Geobacillus sp.TC-S8 by identification of morphological characteristics and 16S rDNA sequence.Ferment condition and character of the extracellular cellulase of Geobacillus sp.TC-S8 were analyzed with 3,5-dinitrosalicylic acid.The enzyme yield of strain TC-S8 reached its peak（229 mU·mL^-1） after culturing 36 h at the conditions of initial pH of culture medium was 6.5,temperature was 60 ℃,broth content was 20%,inoculum was 2% and rotation speed was 120 r·min^-1.The optimum temperature of the cellulase excreted by strain TC-S8 was 60-70 ℃ and the optimum pH was 7.0.The degradation products were mainly glucose and a little cellobiose.