以从海南三亚近海海水中采集的样品为研究对象,利用平板筛选法筛到一株产酯酶的中度嗜盐菌菌株LYG1-1。通过形态学、生理生化及16S rRNA 序列分析,发现该菌株为革兰氏阴性菌,其最适生长温度为30℃,最适生长pH 为7.5,最适NaCl浓度为10%。16S rRNA基因序列分析显示,菌株LYG1-1与Halomonas salina 亲缘性最近,16S rRNA基因序列相似性为99.72%。在含10%NaCl的0.05mol·L-1 Tris-HCl(pH 8.0)缓冲液中,45℃条件下作用,酶活性最高,40℃处理24h仍保持83%的活性。金属离子浓度为5mmol·L-1时, Ca2+、Mg2+对菌株LYG1-1酶活具有明显的激活作用, Hg2+表现出强烈的抑制作用。%Using plate screening method, a moderately halophilic strain LYG1-1 was isolated from seawater sample offshore of Sanya. According to physiological and biochemical characterizations, 16S rRNA sequences and phylogenetic analysis, cells were Gram-negative. It grew best at 30℃, pH 7.5 and with the presence of 10%NaCl. Phylogenetic analysis based on 16S rRNA gene sequence showed that it belonged to the genus Halomonas, having the highest similarity (99.72%) with Halomonas salina. The maximum esterase activity was observed at 45℃, pH 8.0. The effects of various divalent cations were studied based on the activity of esterase from Halomonas sp. The concentrations of 5 mmol·L-1 Mg2+and Ca2+enhanced the esterase activity of LYG1-1, while the presence of Hg2+strongly inhibited its activity.
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