一株瘤胃源产纤维素酶菌株的筛选、鉴定及其酶学特性研究

摘要

A strain with high yield cellulase was screened from rumen fluid of Tibetan cattle, and identified by morphological observation, physiological and biochemical experiments and molecular biological techniques, and its enzymatic characteristics were preliminarily studied. The results showed that a strain N30 with high yield cellulase was screened, and identified as Paenibacillus lautus. The highest cellulase activity was 15.6 U/ml by fermentation for 72 h. The optimum reaction temperature of the cellulase was 55 ℃, and the relative enzyme activity of the cellulase was higher than 80％ between 10 ℃ and 35 ℃. The optimum reaction pH was 4.5, and the relative enzyme activity of the cellulase was more than 60％ at pH 3.5 to 9.0. The metal ions Ag2+, K+, Mg2+, Fe2+, Zn2+, Co+ could promote the cellulase activity, while metal ions Cu2+ could inhibit the cellulase activity.%该研究从西藏黄牛瘤胃液中筛选一株高产纤维素酶的菌株,通过形态观察、生理生化试验和分子生物学技术对其进行鉴定,并对其酶学特性进行初步研究.结果表明,筛选获得一株高产纤维素酶的菌株N30,并被鉴定为灿烂类芽孢杆菌(Paenibacillus lautus),其发酵72 h时,纤维素酶活力最高,为15.6 U/mL.该纤维素酶的最适反应温度为55 ℃,在10～35 ℃之间保持较高的酶活力,相对酶活力>80％;最适反应pH值为4.5,在pH 3.5～9.0时相对酶活>60％;金属离子Ag2+、K+、Mg2+、Fe2+、Zn2+、Co+对纤维素酶活力有促进作用,而金属离子Cu2+对纤维素酶活力有抑制作用.