Vanwonterghem Inka, Jensen Paul D, Rabaey Korneel, Tyson Gene W
1] Advanced Water Management Centre (AWMC), The University of Queensland, St Lucia, QLD 4072, Australia [2] Australian Centre for Ecogenomics (ACE), School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia.
Advanced Water Management Centre (AWMC), The University of Queensland, St Lucia, QLD 4072, Australia.
Sci Rep. 2015 Feb 16;5:8496. doi: 10.1038/srep08496.
Anaerobic digestion is a widely used technology for waste stabilization and generation of biogas, and has recently emerged as a potentially important process for the production of high value volatile fatty acids (VFAs) and alcohols. Here, three reactors were seeded with inoculum from a stably performing methanogenic digester, and selective operating conditions (37°C and 55°C; 12 day and 4 day solids retention time) were applied to restrict methanogenesis while maintaining hydrolysis and fermentation. Replicated experiments performed at each set of operating conditions led to reproducible VFA production profiles which could be correlated with specific changes in microbial community composition. The mesophilic reactor at short solids retention time showed accumulation of propionate and acetate (42 ± 2% and 15 ± 6% of CODhydrolyzed, respectively), and dominance of Fibrobacter and Bacteroidales. Acetate accumulation (>50% of CODhydrolyzed) was also observed in the thermophilic reactors, which were dominated by Clostridium. Under all tested conditions, there was a shift from acetoclastic to hydrogenotrophic methanogenesis, and a reduction in methane production by >50% of CODhydrolyzed. Our results demonstrate that shortening the SRT and increasing the temperature are effective strategies for driving microbial communities towards controlled production of high levels of specific volatile fatty acids.
厌氧消化是一种广泛应用于废物稳定化和沼气生产的技术，最近已成为生产高价值挥发性脂肪酸（VFA）和醇类的潜在重要工艺。在此，三个反应器接种了来自稳定运行的产甲烷消化器的接种物，并应用了选择性操作条件（37°C和55°C；12天和4天的固体停留时间）来限制甲烷生成，同时维持水解和发酵。在每组操作条件下进行的重复实验产生了可重复的VFA生产曲线，这些曲线可与微生物群落组成的特定变化相关联。短固体停留时间的中温反应器显示出丙酸盐和乙酸盐的积累（分别占水解COD的42±2%和15±6%），以及纤维杆菌属和拟杆菌目的优势。在以梭菌属为主导的嗜热反应器中也观察到了乙酸盐的积累（>50%的水解COD）。在所有测试条件下，都发生了从乙酸裂解型甲烷生成到氢营养型甲烷生成的转变，并且甲烷产量减少了>50%的水解COD。我们的结果表明，缩短固体停留时间和提高温度是驱动微生物群落实现高水平特定挥发性脂肪酸可控生产的有效策略。
