Klebsiella sp.B-36的分离鉴定及产脂肪酶特性研究

Study on Isolation and Identification of a Klebsiella sp.B-36 and Properties of Lipase

从郑州西郊采集的土壤样品中筛选到一株产耐高温酸性脂肪酶菌株B-36,根据其形态、生理生化特征及16S rDNA序列分析初步鉴定为克雷伯氏菌(Klebsiella sp.)。对该菌株产脂肪酶特性研究结果表明:该酶的适宜作用温度为60℃,适宜pH 4.0,该酶在60℃热处理70 min酶活力可保持在80%以上,说明该酶具有良好的热稳定性。同时,该酶在酸性环境中静置1 h后还保持70%以上的酶活力,说明该酶在酸性条件下较稳定。金属离子Mg2+、Ca2+、Na+以及EDTA对酶有明显的激活作用,Fe3+、Cu2+及Zn2+对酶有抑制作用,K+对酶几乎没有影响。

A strain B -36 producing thermostable acidic lipase was isolated from soils of the western suburb in Zhengzhou. According to its morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis,the strain was identified as Klebsiella sp. After taking research on the enzymatic properties of the strain B -36 producing lipase, the results showed that the optimum enzyme reaction temperature was 60 ℃, with pH 4.0; the enzyme activity could be maintained at 80% or more after being heating treated for 70 min at 60 ℃, which could be a evidence of good thermal stability. Meanwhile, the enzyme activity was still maintained at more than 70% after handled in an acidic environment for i h, indicating that the enzyme was stable under acidic conditions. The metal ions of Mg2 ＋, Ca2 ＋ , Na ＋ and EDTA significantly enhanced the lipase＇s activity, whereas Fe3 ＋ , Cu2 ＋ and Zn2 ＋ reduced the lipase activity, K ＋ had little effect.