产低温纤维素酶菌株的分离鉴定及产酶特征研究

Screening,Identification of a Cold-active Cellulase Strain and Characterization of Its Cellulose Production

自东帕米尔高原布伦口湖群湿地10 cm草甸中分离到一株高酶活低温纤维素酶产生菌BLKC2,经16S rDNA序列鉴定为枯草芽孢杆菌(Bacillus subtilis)。BLKC2在10℃低温条件下保持繁殖能力,在20℃,pH 7.0条件下发酵72 h,酶活力达到最大值28.7 U/mL。酶学特性显示,BLKC2分泌的粗酶最适催化温度为30℃,对热敏感,最适反应pH8.0左右,在pH 7.0～9.0的偏碱性环境中酶活力较稳定,Mn^(2+)、Zn^(2+)、Mg^(2+)对酶反应有明显激活作用,而Fe^(3+)、Cu^(2+)则抑制了酶反应。

A strain BLKC2 producing cold active cellulase was isolated from 10 cm depth under the sur face layer at Bulunkou lakes group alpine wetland.It was identified as Bacillus subtilis by16S rDNA sequence analysis.Strain BLKC2 could still reproduce at 10 ℃.The results of cellulose producing research showed that the optimum temperature was 20 ℃,the optimum pH value was 7.0.Under this condition,the highest cellulose activity reached 28.7 U/mL in fermentation for 72 h.Enzymatic properties showed that the optimum reaction temperature was 30 ℃,but thermal stability of the enzyme was relatively poor.The enzyme showed the highest activity at pH 8.0,and the kept its satisfactory stability at pH 7.0-9.0.Mn^2+,Zn^2+,Mg^2+ were the activators and Fe^3+,Cu^2+ were the inhaibitiors of the enzyme.