有机负荷对杂交狼尾草和牛粪混合发酵系统内微生物群落的影响

Effect of OLRs on the Microorganism Community of Co-Digestion of Hybrid Pennisetum and Cow Manure

选取杂交狼尾草和牛粪为原料,研究有机负荷和原料配比对混合原料发酵系统内微生物群落组成的影响。研究结果表明,属水平上系统内优势细菌有梭菌属(Clostridum)、普雷沃菌属(Prevotella)、互养棍状菌属(Syntrophorhabdus)、假单胞菌属(Pseudomonas)和噬蛋白质菌属(Proteiniphilum)等;优势产甲烷古菌有甲烷丝菌属(Methanothrix)和甲烷蝇菌属(Methanolinea)等。当系统有机负荷低于4.5 g VS/(L·d)(GC31)或5.0 g VS/(L·d)(GC11)时,贡献系统内丙酸和丁酸累积的梭菌属等细菌菌属平均相对丰度为0.53%,而参与丙酸/丁酸转化细菌菌属的平均相对丰度为1.27%,有助于丙酸和丁酸转化;同时,假单胞菌属和噬蛋白质菌属等贡献系统氨氮积累的菌属丰度较低,此时甲烷丝菌属是优势产甲烷菌属,乙酸型产甲烷途径是主要的转化途径。随着有机负荷升至5.0 g VS/(L·d)或5.5 g VS/(L·d)时,贡献丙酸和丁酸累积的细菌菌属的相对丰度升高了240%,而参与丙酸/丁酸转化细菌菌属丰度降低了90%,导致系统内丙酸和丁酸浓度增加;此时与系统中氨氮浓度升高有关的假单胞菌属和噬蛋白质菌属丰度增加了210%;同时乙酸营养型产甲烷菌属丰度降低,与系统中乙酸浓度增加有关。由此可见,原料配比和有机负荷可影响系统内微生物群落组成结构,迚而影响系统产气性能。

The effects of organic loading rates(OLRs)and raw material ratio on microbial community composition in the co-digestion system were studied by selecting hybrid pennisetum and cow manure as raw materials.The results showed that the dominant bacteria in the system at the genus level included Clostridum,Prevotella,Syntrophorhabdus,Pseudomonas,Proteiniphilum,etc.;and the dominant archaea included Methanothrix and Methanolinea,etc.When the OLRs was less than 4.5 g VS/(L·d)(GC31)or 5.0 g VS/(L·d)(GC11),the average relative abundance of the genus in the system was 0.53%,contribute to the accumulation of propionic acid and butyric acid.While the abundance of the genus participating in propionic acid and butyric acid conversion was 1.27%,which contributes to the conversion of propionic acid and butyric acid.Meanwhile,the relative abundance of the genus contributing to the accumulation of total ammonia nitrogen(TAN)was low,and the genus Methanothrix was the dominant methanogens,suggesting that the acetic acid-type methanogenic pathway was the main conversion pathway.As the OLRs increased to 5.0 g VS/(L·d)or 5.5 g VS/(L·d),the relative abundance of the genus contributing to the accumulation of propionic acid and butyric acid increased by 240%,while the abundance of the genus participating in propionic acid and butyric acid conversion decreased by 90%,leading to an increase in the concentrations of propionic acid and butyric acid in the system.Correspondingly,the relative abundance of the genus Pseudomonas and Proteiniphilum increased by 210%,which contributing to the TAN accumulation.Meanwhile,the abundance of acetic acid-type methanogens decreased,which was related to the increase of acetic acid concentration.It can be seen that the ratio of raw materials and organic load can affect the composition of microbial community in the co-digestion system,thereby affects the biogas yield of the system.