一株产纤维素酶细菌的分离鉴定及酶学特性研究

摘要

A cellulase-producing bacteria strain JJ-3 with high activity was isolated from the soil containing rotted leaves, which was identified asKlebsiella oxytoca based on the 16S rRNA sequence analysis. The optimal enzyme-producing conditions of strain JJ-3 was investigated and was as follows:filter paper as carbon source, peptone as nitrogen source, pH8.0, three-day fermentation. And the fermentation culture had higher FPase activity under neutral and alkaline conditions, with 118.7 U/mL(pH7.0), 167.8 U/mL(pH8.0), 120 U/mL(pH9.0). The results of enzymatic characterization showed that the optimal pH and temperature for enzyme reaction was 7.0 and 40℃, respectively. FPase was sensitive to temperature, while it kept good stability during the pH7.0 to 8.0. This study suggested that the cellulase from strain JJ-3 meets the request of neutral and alkaline cellulase.%从采集的含腐烂树叶的土壤中，筛选到1株产纤维素酶能力较高的菌株JJ-3，经16S rRNA基因序列分析，鉴定该菌株为产酸克雷伯氏杆菌（Klebsiella oxytoca）。产酶条件及酶学特性研究表明：以滤纸为碳源、蛋白胨为氮源、初始pH为8.0的培养基中发酵3 d更利于纤维素酶的合成；菌株发酵液在中性和碱性条件下均有较高的滤纸酶活力，分别可达118.7 U/mL（pH7.0），167.8 U/mL（pH8.0）和120 U/mL（pH9.0）；所产纤维素酶的最适酶反应pH为7.0，最适酶反应温度为40℃，对温度比较敏感，在pH7.0-8.0的范围内具有较好的稳定性，能满足中性和碱性纤维素酶的要求。