摘要
采用生物强化方法强化水稻秸秆好氧水解过程,并研究绿色木霉及添加量(占总料液质量分数3％、5％、7％和9％)对其发酵特性的影响.好氧水解阶段生物强化时间为24h,随后在35℃条件下进行厌氧发酵产甲烷潜力测试试验.结果表明,与对照组相比,添加绿色木霉进行生物强化各组的木质纤维素降解率、挥发性脂肪酸(VFAs)产量及产气率均有不同程度的提高,VFAs均以乙酸为主.利用Modified Gompertz对累积产甲烷量进行拟合,拟合结果较好,绿色木霉添加量为3％、5％、7％、9％的各预处理试验组累积产甲烷量分别为198.28、211.351、228.44、234.78 mL/g,比CK对照组产甲烷量分别提高18.89％、26.72％、36.96％、40.76％,添加7％绿色木霉组的综合效果最好,在此条件下半纤维素、纤维素、木质素降解率分别为36.86％、31.57％、7.43％,甲烷产量较CK组提高36.96％.好氧水解过程中优势菌群为厚壁菌门(Firmicutes)、绿弯菌门(Chloroflexi)、变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)等,其中厚壁菌门(Firmicutes)相对丰度随水解时间的延长而减少,绿弯菌门(Chloroflexi)和拟杆菌门(Bacteroidetes)相对丰度增加,表明添加菌剂能够改变菌群结构,促进好氧水解反应的进行.
Abstract
The aerobic hydrolysis process of rice straw was enhanced by biological reinforcement method,and the effects of green Trichoderma and its addition amount(3％,5％,7％,and 9％of the total feed mass fraction)on its fermentation characteristics were studied.The biological enhancement time in the aerobic hydrolysis reactor was 24 h,followed by anaerobic fermentation methane production potential testing under 35℃ conditions.The results showed that compared with the control group,the addition of Trichoderma viride for biological enhancement resulted in varying degrees of improvement in the degradation rate of lignocellulose,production of volatile fatty acids(VFAs),and gas production rate in each group,with acetic acid being the main component of VFAs.The cumulative methane production was fitted by using Modified Gompertz,and the fitting results were good.The cumulative methane production of each pre-treatment experimental group with 3％,5％,7％,and 9％addition of Trichoderma viride was 198.28 mL/g,211.351 mL/g,228.44 mL/g,and 234.78 mL/g,respectively.Compared with that of the CK control group,the methane production was increased by 18.89％,26.72％,36.96％,and 40.76％,respectively.The results showed that the comprehensive effect of adding 7％Trichoderma viride was the best.Under these conditions,the degradation rates of hemicellulose,cellulose and lignin were 36.86％,31.57％,and 7.43％,respectively,and the methane production was increased by 36.96％.The dominant bacterial communities during aerobic hydrolysis were Firmicutes,Chloroflexi,Proteobacteria,and Bacteroidetes.Among them,the relative abundance of Firmicutes was decreased with the prolongation of hydrolysis time,while the relative abundance of Chloroflexi and Bacteroidetes was increased,indicating that the addition of microbial agents could change the structure of bacterial communities and promote the progress of aerobic hydrolysis reaction.
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