Bacterial esterases are gaining the importance in pharmaceuticals and agrochemical industries due to their excellent biocatalytic properties and a wide range of applications. In the present study, a novel gene encoding an esterase (designated as Est-CR) was identified from shotgun metagenomic sequencing data of camel rumen (Camelus dromedarius) liquor. The open reading frame consisted of 1,224bp, which showed 84.03% sequence identity to Bacteroidales bacterium, corresponding to a protein of 407 amino acids and has a catalytic domain belonging to an esterase. Est-CR belonged to family V with GLSMG domain. The purified enzyme with a molecular mass of 62.64 kDa was checked on SDS-PAGE, and its expression was confirmed by western blotting. The enzyme was active and stable over a broad range of temperature (35–65 °C), displayed the maximum activity at 50 °C and pH 7.0. Individually all metal ions inhibited the enzyme activity, while in combination, K²⁺, Ca²⁺, Mg²⁺ and Mn²⁺ metal ions enhanced the enzyme activity. The detergents strongly inhibited the activity, while EDTA (10 mM) increased the activity of the Est-CR enzyme. The enzyme showed specificity to short-chain substrates and displayed an optimum activity against butyrate ester. This novel enzyme might serve as a promising candidate to meet some harsh industrial processes enzymatic needs.

细菌酯酶因其优异的生物催化性能和广泛的应用而在制药和农业化学工业中越来越重要。在本研究中，从骆驼瘤胃 ( Camelus dromedarius ) 酒的鸟枪法宏基因组测序数据中鉴定出一个编码酯酶的新基因（称为 Est-CR） 。开放阅读框由1,224bp组成，与拟杆菌属细菌的序列同一性为84.03%，对应于407个氨基酸的蛋白质并具有属于酯酶的催化结构域。Est-CR 属于 GLSMG 域的家族 V。在SDS-PAGE上检测分子量为62.64 kDa的纯化酶，并通过蛋白质印迹确认其表达。该酶在很宽的温度范围（35-65°C）内具有活性且稳定，在 50°C 和 pH 7.0 时表现出最大活性。所有金属离子单独抑制酶活性，而K ²⁺、Ca ²⁺、Mg ²⁺和Mn ^2+组合金属离子增强了酶的活性。去污剂强烈抑制活性，而 EDTA (10 mM) 增加 Est-CR 酶的活性。该酶对短链底物表现出特异性，并对丁酸酯表现出最佳活性。这种新型酶可能成为满足某些苛刻工业过程酶需求的有希望的候选者。