微生物燃料电池阳极微生物群落对乳酸-丙酸-乳酸底物转换的响应特征

Response of microbial fuel cell anodic microbial communities to substrate switch of lactate-propionatelactate

摘要:

摘要:【目的】为探讨底物波动对微生物燃料电池(MFC)产电效能和阳极微生物群落的影响，【方法】依次以乳酸-丙酸-乳酸为底物，应用不依赖于培养的微生物分子生态学技术，解析单室MFC 启动及底物替换过程中阳极微生物群落的动态学响应特征。【结果】底物的更换过程降低了MFC的产电效能，当改变为新底物后，MFC需要较长的产电恢复期。同时，底物的转换改变了阳极微生物群落结构，Anaeromusa spp.、Pseudomonas spp．以及Thiobacillus thioparus对乳酸底物具有很好的响应，随着乳酸底物的投加而富集;丙酸底物对Dechloromonas spp.和Comamonas testosteroni等类群表现出较强的选择作用;而产电微生物Geobacter spp.由于利用乳酸、丙酸的共同代谢产物乙酸为底物而被逐渐富集，是多种底物替换过程的重叠种群。【结论】本研究表明，MFC的阳极微生物群落组成与投加的底物有较强的对应性，为了减缓底物波动对MFC产电过程的影响，应尽量采用混合有机底物，以提供宽泛的营养生态位，提高种群的功能重叠性。

Abstract:

Abstract:［Objective］To study the effect of substrates variation on the electricity production of microbial fuel cell (MFC) and anodic microbial communities．［Methods］An MFC was started up and operated by feeding in turn with lactate，then with propionate and finally with lactate． The anodic microbial communities were monitored by using cultureindependent microbial molecular ecological techniques．［Results］The switch of substrates markedly affected the power efficiency of MFC. It required relatively long time to recover the electricity generation capability as the substrate was switched． The substrates switch also changed the microbial community structure． Anaeromusa spp.，Pseudomonas spp．and Thiobacillus thioparus were dominated with lactate fed because they were enriched in the presence of lactate． When propionate was supplied as sole substrate，Dechloromonas spp. and Comamonas testosterone were selected． The electricityproducing bacteria，Geobacter spp． ，were enriched by acetate from either lactate or propionate degradation． Hence，Geobacter spp． was an overlapping microbial population in the presence of the two different substrates.［Conclusion］A well correspondence between substrate and anodic microbial community was observed in MFC with switching substrates. To reduce the effect of substrate fluctuation on the MFC electricity production，more complex organic substrate should be provided as broader nutrients which could improve the functional overlap of populations and MFC stability．