一株纤维素降解菌株筛选及在低温好氧堆肥起爆应用

Screening of a lignocellulose degradation psychrotrophs and application to starter of low temperature aerobic composting

为解决北方寒区冬季低温环境下秸秆好氧堆肥起温困难问题,从腐烂秸秆及土壤中筛选可在5℃低温环境下正常生长,且具有木质纤维素降解能力的微生物菌株,为获得低温秸秆好氧堆肥起爆菌剂奠定基础。研究使用刚果红染色法初筛,利用羧甲基纤维素酶(CMC)活性及滤纸崩解试验复筛,再鉴定获得的菌株,最后利用堆肥试验验证其起爆效果。试验筛选到一株耐冷纤维素降解菌LYG-01,其CMC酶活性为1.77 U·mL^(-1),鉴定该菌为Lelliottia sp.。响应面分析结果表明,pH为6.8,培养温度为24.2℃,接种量达到3.12%时,为该菌株最适培养条件。堆肥中处理组在第72小时即达到高温阶段阈值(50℃),此时对照组温度仅升高至37.2℃,处理组高温阶段时间相比对照组延长33%。处理组温度峰值60.2℃,而对照组峰值为58.7℃。据此,可判断该菌可用于制备低温秸秆好氧堆肥起爆菌剂。

In order to solve the problem of straw aerobic composting initiation at low temperatures in northern cold regions in winter,microbial strains were screened out from decomposing straw and soil that could grow normally at low temperatures of 5℃and have the ability to degrade lignocellulose to lay the groundwork for obtaining low temperature straw aerobic composting starter.The initial screening of strain was done using the Congo red staining method.The subsequent screening was done using the filter paper disintegration test and carboxymethyl cellulose(CMC)activity detection methods.The obtained strains were then identified,and the composting test was used to confirm their initiation effects.In this study,Lelliottia sp.was found to be a lignocellulose degradation psychrotrophs bacterium with a CMC enzyme activity of 1.77 U·mL^(-1).According to the findings of response surface analysis,the ideal culture conditions for this strain were pH 6.8,an incubation temperature of 24.2℃,and an inoculum size of 3.12%.The treatment group in the compost achieved the high temperature stage threshold(50℃)in the 72 nd h,whereas the control group's temperature was only 37.2℃ at that time.The treatment group also took 33%longer to reach the high temperature stage than the control group did.The treated group's peak temperature was 60.2℃,whereas the control group's peak temperature was 58.7℃.Therefore,it could be concluded that the bacteria could therefore be employed to create a low temperature straw aerobic composting starter.