Development And Application Of Lignin、Cellulose Degrading Solid Microbial Inoculant For Green Waste Composting

With the continuous expansion of green area in our country,the amount of green waste is increasing,and the recycling of waste has become an important link in the development of green undertakings.Aerobic composting is the main way to reuse green waste,but the high content of lignin and cellulose in green waste leads to problems such as slow progress and poor effects during the composting.At present,the problem is mainly solved by adding microbial inoculant.Compared with liquid microbial inoculant,solid microbial inoculant has the advantages of lower production cost and more conveniently preserved and transported.A lignin-degrading bacterium No.11 and a cellulose-degrading bacterium B4 were respectively prepared into solid microbial inoculant with different degradation function through single factor optimization and orthogonal test.The effect of solid microbial inoculants was tested by simulated composting test.The compound solid microbial inoculant、microbial inoculant No.11、microbial inoculant B4 and commercial microbial inoculant EM was added to green waste composting in the actual environment.The practical application effect of self-made solid microbial inoculant was explored.The main test results were as follows:（1）The optimal immobilization conditions of lignin-degrading solid microbial inoculant No.11 were as follows:with biochar-rice bran as a carrier,10%inoculation amount,8%prot-ectant volume fraction and 15%water content.The amount of the effective living bacteria in the prepared fungus reached 1.26×10¹¹CFU·g^-1and the storage time was more than 12 months.The test results of simulated composting showed that the addition of the inoculantcould incre-ase the enzymatic activities of laccase,manganese peroxidase and lignin peroxidase.Compared with commercial microbial inoculant,the degradation rate of lignin was increased by 8.69%.Compared with the control（without inoculant）,the degradation rate of lignin and cellulose was increased by 23.91%and 8.34%,respectively.（2）The optimal immobilization conditions of cellulose-degrading solid microbial inoculant B4were as follows:with wheat bran as a carrier,1 g/kg sucrose,2 g/kg peptone,10%inoculation amount and material-to-water ratio 1:0.9.Under these conditions,adding 12%sodium alginate as a protective agent.The amount of the effective living bacteria in the prepared fungus after drying reached 4.77×10¹⁰ CFU·g^-1,and the storage time was more than 6 months.The test results of simulated composting showed that the addition of the inoculant could make the cellulase activity value up to 18.24 U·g^-1.Compared with the control（without inoculant）,the degradation rate of cellulose was significantly improved.（3）Outdoor composting experitiments showed that the maximum temperature and average temperature of composting were increased by adding microbial inoculant.After adding self-made solid microbial inoculant No.11 and B4 to green waste composting,the degradation rate of lignin were 30.32%and 25.65%,respectively,and the degradation rate of cellulose were 37.02%and41.47%,respectively.The degradation rate of lignin reached 32.26%after adding compound microbial inoculant,which was better than two self-made solid microbial inoculant alone and commercial microbial inoculant EM.The cellulose degradation rate reached 43.80%,which was higher than the treatment with two self-made solid microbial inoculant alone.Compared with commercial microbial inoculant,the degradation rate of cellulose was no significant difference.At the end of composting,the contents of humic extract、fulvic acid and humic acid in the treatment with compound microbial inoculant were increased by 6.92 g/kg、3.58g/kg and 3.34g/kg respectively,which were higher than other treatments.