玫瑰秸秆与牲畜粪污厌氧消化特性及微生物群落研究

Study on Anaerobic Digestion of Rose Straw Inoculated with Livestock Manure and Its Microbial Community

为了解玫瑰秸秆与猪、牛粪污在不同总固体(total solid,TS)含量厌氧消化中理化性质与微生物群落的动态变化,在常温条件下设置3种TS含量(3%、5%、7%)处理,对产甲烷量及厌氧消化系统的效率和稳定性进行分析,并结合定量荧光原位杂交技术(fluorescence in situ hybridization,FISH)对关键微生物类群进行测定。结果表明,3%TS处理产甲烷量最高且延滞期短(20 d),以挥发性固体(volatile solid,VS)计,75 d累计产甲烷量262.80 mL·g^(-1) VS,比5%TS、7%TS处理分别高16.14%和23.86%。挥发性脂肪酸(volatile fatty acids,VFAs)在3种TS处理中均表现出先上升后降低的趋势。对厌氧消化系统中微生物菌群的分析表明,在3种TS处理下古菌群落中的甲烷八叠球菌目(Methanosarcinales)均为正常产气阶段(30~75 d)目水平下优势菌群,其中5%TS处理试验结束时最高丰度为77.46%;而细菌群落中脱硫弧菌目(Desulfovibrionales)为目水平下优势菌群,在75 d时,脱硫弧菌目的细菌丰度在3%TS、5%TS处理下相较于开始时(0 d)分别下降8.36%和1.24%,而7%TS处理上升1.68%。综上所述,3%TS处理为最优条件,具有最大产气量和最短的延滞期,微生物菌群的组成相对稳定高效,3%TS处理的厌氧消化系统可以有效地提高玫瑰秸秆厌氧消化性能。

To understand the physiochemical properties of anaerobic digestion of rose straw inoculated with livestock manure under different total solid(TS)contents and the dynamic variations of microbial communities involved,methane production and stability of the anaerobic digestion systems were investigated at 3 different TS contents(3%,5%,7%)at room temperature and the composition of key microbial groups in these systems were identified using quantitative fluorescence in situ hybridization(FISH).The results showed that 3%TS treatment had a maximus methane production and a shortest delay period(20 d).Based on the volatile solid(VS),its cumulative methane production after 75 d was 262.80 mL·g^(-1) VS,being 16.14%and 23.86%higher than that of the 5%TS and 7%TS treatments,respectively.The volatile fatty acids(VFAs)contents produced in the anaerobic digestions with 3%,5%,and 7%TS contents increased in the early stage of the experiments and then gradually decreased to the end of the experiments.FISH analysis showed that under all TS contents,the Methanosarcinales were the dominant methanogens during the normal gas production period(30~75 d),accounting for 77.46%of the total methanogens in 5%TS content.The Desulfovibrionales were the dominant bacteria,at the end of the experiments(75 d),the abundance of Desulfovibrionales decreased by 8.36%and 1.24%with 3%and 5%TS contents respectively but increased by 1.68%with 7%TS content.In summary,3%TS was the optimal TS content for anaerobic digestion of rose straw,with maximum gas production,shortest delay period,and relatively stable and efficient microbial community composition,which could most effectively improve the anaerobic digestion performance of rose straw.