Laothanachareon Thanaporn, Kanchanasuta Suwimon, Mhuanthong Wuttichai, Phalakornkule Chantaraporn, Pisutpaisal Nipon, Champreda Verawat
Enzyme Technology Laboratory, Bioresources Technology Unit, National Center for Genetic Engineering and Biotechnology, Thailand Science Park, Khlong Luang, Pathum Thani 12120, Thailand.
The Joint Graduate School for Energy and Environment (JGSEE), King Mongkut's University of Technology Thonburi, Thungkru, Bangkok 10140, Thailand.
J Environ Manage. 2014 Nov 1;144:143-51. doi: 10.1016/j.jenvman.2014.05.019. Epub 2014 Jun 16.
Dark fermentation is an attractive process for generation of biohydrogen, which involves complex microbial processes on decomposition of organic wastes and subsequent conversion of metabolic intermediates to hydrogen. The microbes present in an upflow anaerobic sludge blanket (UASB) reactor for waste water treatment were tested for application in batch dark fermentation of food waste at varying ratios of feedstock to heat-treated microbial inoculum (F/M) of 1-8 (g TVS/g TVS). Biohydrogen yields between 0.39 and 2.68 mol H2/mol hexose were obtained, indicating that the yields were highly dependent on the starting F/M ratio. The highest H2 purity of 66% was obtained from the first 8 h of fermentation at the F/M ratio of 2, whereas the highest H2 production was obtained after 35 h of fermentation at the F/M ratio of 5. Tagged 16S rRNA gene pyrosequencing showed that the seed culture comprised largely of uncultured bacteria with various Proteobacteria, Bacteroidetes, and Firmicutes, while the starting food waste contained mainly lactic acid bacteria. Enrichment of Firmicutes, particularly Clostridia and lactic acid bacteria occurred within 8 h of the dark fermentation and the H2 producing microcosm at 35 h was dominated >80% by Clostridium spp. The major H2 producer was identified as a Clostridial strain related to Clostridium frigidicarnis. This work demonstrated the adaption of the microbial community during the dark fermentation of complex food waste and revealed the major roles of Clostridia in both substrate degradation and biohydrogen production.
暗发酵是一种颇具吸引力的生物制氢过程，它涉及有机废物分解以及随后代谢中间体转化为氢气的复杂微生物过程。对用于废水处理的上流式厌氧污泥床（UASB）反应器中的微生物进行了测试，以考察其在不同原料与热处理微生物接种物比例（F/M）为1 - 8（克挥发性悬浮固体/克挥发性悬浮固体）的食物垃圾分批暗发酵中的应用。生物氢产量在0.39至2.68摩尔氢气/摩尔己糖之间，这表明产量高度依赖于起始F/M比例。在F/M比例为2时，发酵的前8小时获得了最高66%的氢气纯度，而在F/M比例为5时，发酵35小时后获得了最高的氢气产量。标记的16S rRNA基因焦磷酸测序表明，种子培养物主要由各种变形菌门、拟杆菌门和厚壁菌门的未培养细菌组成，而起始食物垃圾主要含有乳酸菌。在暗发酵的8小时内厚壁菌门，特别是梭菌属和乳酸菌得以富集，在35小时时产氢微观世界中超过80%由梭菌属主导。主要的产氢菌被鉴定为与嗜冷肉梭菌相关的梭菌菌株。这项工作证明了在复杂食物垃圾暗发酵过程中微生物群落的适应性，并揭示了梭菌属在底物降解和生物制氢中的主要作用。
