解淀粉芽孢杆菌复合菌剂对玉米秸秆的降解作用及表征  

Analysis of the degradation of corn stalk fermented by complex bacteria composed of two Bacillus amyloliquefaciens strains

作　　者：李红亚[1] 李文[1] 李术娜[1] 王树香[1] 李猛[1] 田苗苗[1] 朱宝成[1] 

机构地区：[1]河北农业大学生命科学学院,河北保定071000

出　　处：《草业学报》2017年第6期153-167,共15页Acta Prataculturae Sinica

基　　金：河北省科技支撑计划项目(12226605);河北省教育厅科学技术研究项目(2011232)资助

摘　　要：为获得能提高秸秆饲草品质的微生物发酵菌剂,本研究在前期获得2株具有木质素和纤维素降解能力的解淀粉芽孢杆菌菌株的基础上,将两者混配成复合菌剂,考察复合菌剂对玉米秸秆的降解作用,并通过傅立叶红外光谱(FTIR)、核磁共振氢谱(1 H-NMR)、扫描电镜(SEM)及气质联用色谱(GC/MS)等技术对玉米秸秆的微观结构及降解产物进行表征。研究发现,复合菌剂可以有效降解玉米秸秆中的木质纤维素。在发酵24d时,玉米秸秆中木质素、纤维素和半纤维素的降解率分别达到48.4%,30.5%和41.4%。FTIR和1 H-NMR谱图中能观察到木质纤维素分子结构中主要连接共价键,如木质素单体间的β-O-4和β-β键、木质素与碳水化合物连接键以及碳水化合物中糖环内的价键等明显断裂,木质纤维素被部分降解;SEM扫描电镜图则显示发酵后秸秆的组织结构出现松散和破坏。发酵后秸秆中小分子物质的GC/MS分析结果显示,其中包含苯丙胺和苯丙酸等保留苯丙烷结构单元的木质素单体衍生物以及苄醇和苯甲酸酯类等木质素单体被进一步降解后的芳香族化合物。玉米秸秆中碳水化合物的GC/MS分析结果表明:复合菌剂可将玉米秸秆中的结构性多糖等大分子碳水化合物降解成葡萄糖、木糖、甘露糖及乳糖等还原性单糖。并利用这些还原性单糖生长代谢,进一步产生乙二醇、丙三醇及短链脂肪酸类等代谢产物。以上研究结果表明,解淀粉芽孢杆菌复合菌剂可有效降解玉米秸秆中的木质纤维素,在玉米秸秆饲草化利用中极具应用前景。In order to obtain a complex bacteria agent that can be used in the fermentation of corn stalk and improve its quality as silage,two Bacillus amyloliquefaciens strains with high lignocellulose-degrading ability were mixed to make a complex agent whose degradation effect could be studied.The microstructure and degradation products of corn stalk inoculated with the complex bacteria agent were analyzed using FTIR,1 H-NMR,SEM and GC/MS.Fermentation tests showed that the microbial agent efficiently degraded lignocellulose in corn straw.When the agent was inoculated for 24 days,the degradation rate of lignin,cellulose and hemicellulose reached 48.4%,30.5% and 41.4% respectively.FTIR and 1 H-NMR spectrum analysis showed that the main linking covalent bonds,such asβ-O-4andβ-βlinkages between the lignin monomers,the bonds connecting the lignin to cellulose and the carbohydrate bonds in lignocellulose's molecular structure,were all broken.The complete destruction of plant tissue structure was also observed with electron microscope scanning.GC/MS analysis of low-molecule substances in the fermented corn stalk showed that the lignin was degraded into small molecular aromatic compounds,including amphetamine and phenylpropionic acid,monomers produced by the depolymerization of lignin,and benzyl alcohol and benzoic acid esters,which are degradation products of lignin phenyl propane monomers.GC/MS analysis of carbohydrate degradation products showed that the complex bacteria could not only convert cellulose,hemicellulose and other macromolecule carbohydrates into reducing monosaccharides,such as glucose,xylose,mannose and galactose,but that it could also metabolize these monosaccharides into glycol,glycerol and short-chain fatty acids.In conclusion,these results show that the complex bacteria agent effectively degrades lignocellulose and could be widely used to convert corn stalk into high quality forage.

关 键 词：解淀粉芽孢杆菌 复合菌剂 玉米秸秆 降解 表征 

分 类 号：S816[农业科学—饲料科学]