目的 从安徽庐江汤池温泉中分离得到一株嗜热菌，通过分子生物学手段对其进行鉴定，研究其形态特征和生长特性，并对其产纤维素酶条件进行优化。研究可为其在今后的生物科学研究和工业应用方面提供一定的参考。方法 通过高温培养筛选分离又得到一株嗜热菌，测定其 16S rDNA 基因序列，经过比对序列和构建系统发育树及菌体和菌落形态的观察确定其分类学地位，并研究其生长特性，通过研究接种龄、发酵培养基初始 pH、接种量、发酵温度、转速和发酵时间等因素对产纤维素酶的影响，初步优化产纤维素酶的条件。结果 从庐江汤池温泉水中又筛选分离得到一株嗜热菌，将其命名为 LJTC-2。该菌为革兰氏阳性菌，呈杆状，属于地芽孢杆菌属；最高耐受 73°C，最适生长pH为 7.0 左右。菌株 LJTC-2 产纤维素酶的最佳条件初步确定为：接种龄为 36 h，发酵培养基初始pH6.0，接种量 2%，发酵温度为 60°C，转速为 180 r-min-1，发酵时间为 60 h，酶活力最高，为 183 mU.mL-1，比优化前提高了 17%。结论 LJTC-2 菌株是地衣芽孢杆菌，能耐受 73摄氏度高温，初步确定菌株 LJTC-2 在接种龄为 36 h、发酵培养基初始 pH6.0、接种量 2%，60°C、180 r.min-1 的条件下发酵60 h，纤维素酶酶活最高。
[Objective] One thermophilic bacterium was isolated from the hot spring in Tangchi, Lujiang, Anhui,and identified by molecular biological methods to study its morphological, physiological and growth characteristics,and the conditions of cellulase production were optimized. This study can provide reference for its biological science research and industrial application in the future. [Methods] Another thermophilic bacterium was isolated by high temperature culture, and its 16S rDNA gene sequence was determined. Its taxonomic status was determined by sequence alignment, phylogenetic tree construction and observation of cell and colony morphology. And its growth characteristics were studied. Through study of the effects of inoculum age, initial pH of fermentation medium, inoculum amount, fermentation temperature, rotation speed and fermentation time on cellulase production the cellulase production conditions were preliminarily optimized. [Results] Another thermophilic bacterium was isolated from the hot spring in Tangchi, Lujiang for the first time, which was named LJTC-2. The bacterium was Gram-positive and rod-shaped, belonging to Geobacillus. Its highest tolerance temperature was 73 °C and its optimum growth pH was about 7.0. The optimal fermentation conditions of LJTC-2 for cellulase production were determined as follows: inoculation age of 36 h, initial pH of fermentation medium of 6, inoculation amount of 2%, fermentation temperature of 60 °C, rotation speed of 180 r.min-1, fermentation time of 60 h. Under these conditions, the enzyme activity was 183 mU.mL-1, which was 17% higher than that before optimization. [Conclusion] The strain LJTC-2 was Geobacillus, and could tolerate high temperature of 73 °C. The results showed that LJTC-2 had the highest cellulase activity under the conditions of inoculation age of 36 h, initial pH of fermentation medium of 6, inoculation amount of 2%, 60°C , 180 .min-1 and fermentation time of 60 h.
