一株高产酯酶中度嗜盐菌的分离、鉴定及酯酶部分酶学性质的研究

利用平板筛选法从盐场卤水池中筛选到一株高效降解Tween 20的中度嗜盐菌DF-B6菌株。通过形态学、生理生化及16S rDNA序列分析确定该菌株为Idiomarina属的成员。底物特异性实验确定DF-B6菌株分泌的脂裂解酶为酯酶, 而非脂肪酶。在含8% NaCl的0.05 mol/L Tris-HCl (pH 8.0)缓冲液中, 50°C条件下作用, 酶活性最高。当反应液中金属离子浓度为10 mmol/L时, Mg2+、Ca2+和Mn2+对酶活有激活作用, 而Zn2+、Fe3+和Cu2+则对酶反应有抑制作用。

Isolation and Characterization of a Moderately Halophilic Bacterium High-producing Esterase

A moderately halophilic bacterium strain DF-B6 capable of degrading Tween 20 was isolated from solar saltern by plate method. Based on the phenotype, physiological and biochemical characteristics, and the phylogenetic analysis of 16S rDNA sequence, strain DF-B6 was identified as Idiomarina. The substrate specificity test showed that the lipolytic enzyme from strain DF-B6 was an esterase, and not a lipase. The maximum esterase activity was observed in 8% NaCl concentration at 50°C, pH 8.0. The effect of various divalent cations was studied on the activity of esterase from Idiomarina sp. DF-B6 at the concentration of 10 mmol/L, Mg2+, Ca2+ and Mn2+enhanced the esterase activity, while Zn2+, Fe3+ and Cu2+ inhibited its activity.