Bioforsk, Norwegian Institute for Agricultural and Environmental Research, Frederik A. Dahls vei 20, 1432 Ås ᅟ, Norway.
Department of Microbiology, Oslo University Hospital, P.O. Box 4950, Nydalen, 0424 Oslo, Norway.
Biotechnol Biofuels. 2014 Oct 14;7(1):146. doi: 10.1186/s13068-014-0146-2. eCollection 2014.
Biogas is a renewable energy carrier which is used for heat and power production or, in the form of purified methane, as a vehicle fuel. The formation of methane from organic materials is carried out by a mixed microbial community under anaerobic conditions. However, details about the microbes involved and their function are limited. In this study we compare the metagenomes of four parallel biogas reactors digesting a protein-rich substrate, relate microbiology to biogas performance, and observe differences in these reactors' microbial communities compared to the original inoculum culture.
The biogas process performance during the startup phase of four parallel continuous stirred tank reactors (designated R1, R2, R3, and R4) co-digesting fish waste and cow manure was studied. The microbial composition of the inoculum (day 0) and the four reactors at day 59 was studied and compared using 454 FLX Titanium pyrosequencing. In the inoculum and the reactor samples, the Bacteria Clostridium and Syntrophomonas were highly abundant, and the dominating methanogen was the hydrogenotrophic Methanoculleus. Syntrophic prokaryotes frequently found in biogas reactors with high concentrations of ammonium and volatile fatty acids were detected in all samples. The species Candidatus Cloacimonas acidaminovorans of the candidate phylum Cloacimonetes (WWE1) increased in all reactors and was the dominating bacterium at day 59. In particular, this bacterium showed a very high abundance in R1, which distinguished this reactor significantly from the other reactors in terms of microbial composition. Methane production and the reactor slurry characteristics were monitored in the digestion period. Generally all four reactors operated stably and showed rather similar characteristics. The average methane production in the reactors varied between 0.278 and 0.296 L gVS(-1), with the lowest production in R1.
This study showed that four parallel reactors co-digesting manure and fish waste silage operated stably during a startup phase. Several important Archaea and Bacteria degrading the protein-rich substrate were identified. In particular, microorganisms involved in syntrophic methane production seemed to be important. The detailed characterization of the microbial communities presented in this work may be useful for the operation of biogas plants degrading substrates with high concentrations of proteins.
沼气是一种可再生能源载体，可用于热能和动力生产，或以净化甲烷的形式作为车辆燃料。在厌氧条件下，由混合微生物群落将有机物质转化为甲烷。然而，有关涉及的微生物及其功能的详细信息有限。在这项研究中，我们比较了四个平行的沼气反应器消化富含蛋白质的底物的宏基因组，将微生物学与沼气性能相关联，并观察到这些反应器的微生物群落与原始接种物培养物相比存在差异。
研究了四个平行连续搅拌罐反应器（分别命名为 R1、R2、R3 和 R4）在共消化鱼废物和牛粪便的启动阶段的沼气工艺性能。使用 454 FLX Titanium 焦磷酸测序研究了接种物（第 0 天）和第 59 天的四个反应器的微生物组成，并进行了比较。在接种物和反应器样品中，细菌梭菌属和互营单胞菌属高度丰富，优势产甲烷菌是产氢甲烷菌甲烷微菌属。在所有样品中均检测到经常在含有高浓度铵和挥发性脂肪酸的沼气反应器中发现的共生原核生物。候选门 Cloacimonetes（WWE1）的候选属 Cloacimonas acidaminovorans 增加了所有反应器，并在第 59 天成为主要细菌。特别是，这种细菌在 R1 中的丰度非常高，这使得该反应器在微生物组成方面与其他反应器明显不同。在消化期间监测了甲烷产生和反应器浆液特性。一般来说，所有四个反应器都稳定运行，表现出相当相似的特征。反应器中甲烷的平均产量在 0.278 和 0.296 L gVS(-1) 之间变化，R1 中的产量最低。
本研究表明，四个共消化粪便和鱼废料青贮的平行反应器在启动阶段稳定运行。确定了几种降解富含蛋白质底物的重要古菌和细菌。特别是，参与协同产甲烷的微生物似乎很重要。本工作中提出的微生物群落的详细特征可能对降解高浓度蛋白质底物的沼气厂的运行有用。
