常温和低温纤维素降解菌的分离及其降解特性  

Isolation and Degradation Characteristics of Cellulose-degradation Bacteria at Room and Low Temperature

作　　者：孟建宇[1] 陈勿力吉玛 郭慧琴[1] 冯福应[1] 陈玉萍[1] MENG Jian-Yu;CHEN Wu-Li-Ji-Ma;GUO Hui-Qin;FENG Fu-Ying;CHEN Yu-Ping(College of Life Sciences,Inner Mongolia Agricultural University,Hohhot 010011,China)

机构地区：[1]内蒙古农业大学生命科学学院,呼和浩特010011

出　　处：《农业生物技术学报》2021年第1期73-84,共12页Journal of Agricultural Biotechnology

基　　金：国家自然科学基金(31460002);内蒙古自然科学基金(2018MS03042)。

摘　　要：寻找适合的纤维素降解菌是解决内蒙古等北方地区纤维素有效应用的关键。本研究采用富集培养和纯培养法对内蒙古西部地区的纤维素降解细菌进行分离并分析其降解特性,以期获得一些高效纤维素降解菌。基于16 S rDNA基因序列进行同源性比对以确定种属,用3,5-二硝基水杨酸(3,5-dinitrosalicylic acid,DNS)比色法测定纤维素酶活性,并对酶活较高的菌株进行产酶条件优化。结果表明:总共分离到59株纤维素降解细菌,包括分别在10℃下分离到的36株低温纤维素降解细菌和28℃下分离到的23株常温纤维素降解细菌;16 S rDNA序列分析显示5 9株菌分别属于α-变形菌纲(α-Proteobacteria)、γ-变形菌纲(γ-Proteobacteria)、β-变形菌纲(β-Proteobacteria)、拟杆菌门(Bacteroidetes)以及放线菌门(Actinobacteria)。其中,α-变形菌纲为常温纤维素降解细菌中第1优势菌群,β-变形菌纲和放线菌门为第2优势菌群;γ-变形菌纲为低温纤维素降解细菌中第1优势菌群,拟杆菌门为第2优势菌群。在属水平上,假苍白杆菌属(Pseudochrobactrum)为常温纤维素降解细菌中第1优势菌属,假单胞菌属(Pseudomonas)为第2优势菌属;假单胞菌属为低温纤维素降解细菌中第1优势菌属,鞘氨醇杆菌属(Sphingobacterium,)为第2优势菌属。菌株CB04 (属于纤维菌属(Cellulomonas))的羧甲基纤维素(carboxymethyl cellulose,CMC)酶活在所有菌株中最高,优化后的最佳产酶条件为:酵母提取物为氮源,培养时间为4 d,pH值为7,其CMC酶活可达114.6 U/mL,是极具开发潜力的纤维素酶生产菌菌株。本研究揭示了内蒙古西部地区可培养纤维素降解细菌的类群组成及其纤维素降解能力,为认识和利用纤维素降解菌提供理论依据和实践基础。Finding suitable cellulose degrading bacteria is the key to the effective application of cellulose in Inner Mongolia and other northern regions.In order to obtain some efficient cellulose-degrading bacteria,traditional isolation and enrichment culture technologies were used to isolate cellulose-degrading bacteria from the soil in western region of Inner Mongolia,and the degradation characteristics of cellulose-degradation bacteria were analyzed.A preliminary identification was based on analyzing the similarities of 16 S rDNA gene sequences of the isolates.Cellulase activity was determined by DNS(3,5-dinitrosalicylic acid) method.And the enzyme-producing conditions of the highest enzyme activity cellulase-producing strain was further optimized.The results showed that a total of 59 cellulolytic bacteria were isolated,including 36 cold-adapted cellulose-degrading bacteria isolated at 10 ℃ and 23 cellulose-degrading bacteria isolated at 28 ℃.The 16 S rDNA gene sequences indicated that these strains belonged to Alpha-Proteobacteria,Gamma-Proteobacteria,beta-Proteobacteria,Bacteroidetes,and Actinobacteria,respectively.Alpha-Proteobacteria was the first dominant group of room temperature cellulose-degrading bacteria,beta-Proteobacteria and Actinobacteria were the second dominant group.Gamma-Proteobacteria was the first dominant group of cold-adapted cellulose-degrading bacteria,Bacteroidetes was the second dominant group.At the genus level,Pseudochrobactrum was the first dominant genus of room temperature cellulose-degrading,while Pseudomonas was the second dominant genus,and Pseudomonas was the first dominant genus of cold-adapted cellulose degrading bacteria at low temperature,while Sphingobacterium was the second dominant genus.Among these strains,strain CB04(belonging to Cellulomonas) had the highest carboxymethyl cellulose(CMC) activity.After optimization,the optimal conditions for enzyme production were as follows:the yeast extract was nitrogen source,the culture time was 4 d,the pH value was 7,and the CMC enz

关 键 词：纤维素降解菌 分离 纤维素酶 优化 

分 类 号：S816[农业科学—饲料科学]