一株苜蓿缩合单宁降解菌的筛选及其鉴定  

Screening and identification of a alfalfa condensed tannin-degrading bacterium

作　　者：何金环[1] 李京 芦朋飞 HE Jin-huan;LI Jing;LU Peng-fei

机构地区：[1]河南牧业经济学院食品与生物工程学院,河南郑州450046 [2]东北林业大学生命科学学院,黑龙江哈尔滨150040

出　　处：《饲料研究》2024年第13期94-98,共5页Feed Research

基　　金：河南省科技攻关项目(项目编号:242102110354、232102110124)。

摘　　要：研究旨在筛选鉴定缩合单宁降解菌,为缩合单宁生物降解提供微生物资源支持,并为扩大紫花苜蓿的利用提供参考。以苜蓿根部土壤为菌源,以缩合单宁为唯一碳源的耐受培养基筛选得到一株降解缩合单宁的菌株,对其进行形态学观察、生理生化特征测定、16S rDNA基因序列比对,测定生长曲线,观察菌种固态发酵紫花苜蓿的效果。结果显示:确定筛选出的菌株为Klebsiella sp.,命名为DN-2。菌株DN-2在肉汤培养基上约3 h进入对数期,24 h时菌液在600 nm的光密度(OD_(600 nm)值)为2.405;在含有缩合单宁的营养肉汤培养基上约4.5 h进入对数生长期,20 h达最大OD_(600 nm)值2.35,整体表现为菌株生长的迟缓期延长而稳定期缩短。正丁醇盐酸检测结果显示,菌株DN-2生长36 h对菌液中的缩合单宁降解率高达94.2%。DN-2菌株固态发酵苜蓿结果显示,发酵处理5 d时,缩合单宁降解率达59.73%,可见DN-2菌株对苜蓿中缩合单宁具有良好的降解效果。研究表明,菌株DN-2的筛选对于植物来源的缩合单宁的生物降解及微生物资源的开发具有一定的实践意义,并为苜蓿在动物生产中的扩大应用提供参考。The study aimed to screen and identify tannin-degrading bacteria to provide microbial resources for the biodegradation of condensed tannins and to potentially expand the utilization of alfalfa.A strain capable of degrading condensed tannins was isolated from alfalfa root soil using a tolerance medium with condensed tannins as the sole carbon source.The strain underwent morphological observation,physiological and biochemical characterization,and 16S rDNA gene sequence comparison.The growth curve of the tannin-degrading bacteria was determined,and the effect of the strain on solid-state fermentation of alfalfa was observed.The results showed that the isolated strain was identified as Klebsiella sp.,named DN-2.Strain DN-2 entered the logarithmic phase in about 3 hours on a broth culture medium and reached an optical density(OD_(600 nm) value)of 2.405 at 600 nm after 24 hours.In the nutrient broth medium containing condensed tannins,it entered the logarithmic growth phase in about 4.5 hours,reaching the maximum OD_(600 nm) value of 2.35 after 20 hours,overall showing an extended lag phase and a shortened stationary phase for the strain.n-Butanol hydrochloric acid detection results showed that the degradation rate of condensed tannins in the culture fluid by strain DN-2 after 36 hours of growth was as high as 94.2%.The solid-state fermentation of alfalfa by strain DN-2 showed a tannin degradation rate of 59.73%after five days of fermentation treatment,indicating that strain DN-2 had a good degradation effect on condensed tannins in alfalfa.The study indicates that the screening of strain DN-2 has practical significance for the biodegradation of plant-derived condensed tannins and the development of microbial resources,and provides references for expanding the application of alfalfa in animal production.

关 键 词：紫花苜蓿 缩合单宁降解菌 菌种固态发酵 

分 类 号：S816.7[农业科学—饲料科学]