固定化木质素降解菌对园林废弃物堆肥的影响

Effect of immobilized lignin-degrading bacteria on green waste composting

【目的】以生物质炭和米糠为载体,将木质素降解菌No.11通过固定化的方式制备促进园林废弃物堆肥腐熟的固体菌剂。【方法】通过单因素试验探究接菌量(5%、10%、15%、20%、25%)、保护剂体积分数(0、4%、8%、12%、16%、20%)、含水率(5%、10%、15%、20%、25%)的优化范围,再通过正交试验在该范围内寻找固体菌剂的最佳制备条件。以市售常见有效微生物复合菌(EM菌)菌剂为对比,将制得的菌剂添加到园林废弃物堆肥中,探究其对木质素、纤维素降解和相关酶活力的影响。【结果】木质素降解菌No.11的最佳固定化条件为:接菌量10%、保护剂体积分数8%、含水率15%,制得的菌剂中有效活菌数达1.26×1011 CFU·g−1。园林废弃物堆肥中添加自制菌剂后木质素降解相关酶(漆酶、锰过氧化物酶、木质素过氧化物酶)的活力均得到提高。与添加EM菌相比,木质素降解率提高8.69%;与不添加菌剂相比,木质素降解率提高23.91%,纤维素降解率提高8.34%,堆肥产品达到腐熟标准。【结论】通过固定化木质素降解菌制备的固体菌剂,其有效活菌数符合GB 20287−2006《农用微生物菌剂》的相关要求,将菌剂添加到园林废弃物堆肥中可提高木质素和纤维素降解率,促进堆肥产品腐熟。

[Objective]The purpose of this research is to prepare a kind of solid microbial inoculant to promote green waste composting by immobilizing lignin-degrading bacteria No.11,with biochar-rice bran as a carrier.[Method]Through single factor experiment,the optimal range of inoculation amount(5%,10%,15%,20%,25%),volume fraction of protective agent(0,4%,8%,12%,16%,20%)and water content(5%,10%,15%,20%,25%)were explored,and the best preparation conditions of solid microbial inoculant were found by orthogonal test.Taking a common commercially available microbial inoculant(EM)as an example,the microbial agent was added to the composting process of green waste to explore its effects on lignin and cellulose degradation and related enzyme activities.[Result]The optimal immobilization conditions of lignindegrading bacteria No.11 were as follows:10%inoculation amount,8%protectant volume fraction and 15%water content.The amount of the effective living bacteria in the prepared fungus reached 1.26×1011 CFU·g−1.Enzyme activities related to lignin degradation(laccase,manganese peroxidase,and lignin peroxidase)were promoted after adding self-made microbial inoculant.Lignin degradation rate increased by 8.69%compared with the addition of EM bacteria.Compared with the control(without inoculant),the degradation rate of lignin and cellulose increased by 23.91%and 8.34%,respectively,and the compost products reached the maturity standard.[Conclusion]The number of effective viable bacteria of the solid microbial inoculant prepared by immobilizing lignin-degrading bacteria complies with the requirements in Microbial Inoculants in Agriculture(GB 20287−2006).Adding the inoculant to green waste compost can improve the degradation rate of lignin and cellulose and promote the maturity of compost products.