降解未处理纤维素厌氧混合菌群的筛选及功能

Selection and function of an anaerobic microbial community with raw cellulose degradation ability

为获得高效稳定的原木质纤维素降解微生物,利用限制性培养手段,从瘤胃残渣中筛选出了可以体外培养、分解能力强且性能稳定的纤维素厌氧降解菌群FYG-2.该菌群在38.5℃,pH6.4～6.8条件下,5 d内可以使1.00 g滤纸完全崩解.转接30代,其降解性能仍保持稳定,且纤维素底物的灭菌与否均不影响其分解.以底物失重率、纤维素酶活和葡萄糖质量浓度为参数,考查了FYG-2对纤维素的分解特性:同预处理后的木质纤维素相比,FYG-2更易于降解天然木质纤维素.在初始接菌量为15%,培养3 d时,FYG-2的酶活最高(159.7 IU).从FYG-2中分离出7株纯菌,但其纤维素酶活均低于FYG-2.纯菌回接实验表明,混合菌群中的协同作用很可能存在于纤维素降解菌与非纤维素降解菌之间或存在于可培养微生物与不可培养微生物间.

An anaerobic microbial community cultured in vitro with efficient and stable ability of cellulose degradation was obtained from rumen residue by the techniques of restricted cultivation,which was named as FYG-2.The characteristics of FYG-2 for cellulose degradation were investigated by taking enzymic activity,gravimetry and glucose concentration as parameter.FYG-2 can hydrolyze 1.00 g filter paper completely within 5 d at the condition of 38.5 ℃ and pH6.4-6.8,and degrade both non-sterilized and sterilized substrate and its degradation ability keeps stable after 30 generations.It can degrade natural lignocellulosic materials more easily than pretreated one.The highest enzyme activity（159.7 IU） was obtained with 15 percents initial seed ratio and after 3 d cultivation.Seven pure cultures were separated from FYG-2,however,all their enzymic activities were far lower than FYG-2.This phenomenon demonstrated that strong synergy probably existed in the cellulose-degrading microorganisms and non-cellulose-degrading microorganisms or in the cultured microorganisms and uncultured microorganisms.