有机废物厌氧发酵生物合成己酸研究进展

RESEARCH PROGRESS ON CAPROIC ACID PRODUCTION FROM ORGANIC WASTE BY ANAEROBIC FERMENTATION

厌氧发酵处理有机废物并合成高价值羧酸盐的技术日趋成熟。尤其是己酸作为产物之一,因其附加值高,易于分离,用途广泛,越来越受到关注。微生物合成己酸需要电子供体及受体。详细介绍了乙醇、乙酸分别作为电子供体、受体合成己酸的机理——逆β氧化反应,总结合成己酸底物以及影响合成的因素(温度、pH值、水力停留时间、竞争路径、氢气分压、底物比例、氮源等)。目前采用科氏梭菌以乙醇为电子供体来合成己酸的技术较成熟,探索了利用乳酸为电子供体合成己酸的代谢机理,并指出开发乳酸转化合成己酸的技术可成为未来发展方向。

High-value carboxylate synthesis during organic waste treatment via anaerobic fermentation technology has become more and more mature.Especially,as one of the final products,caproic acid gained much more attentions,because of its high added-value,easy separation and wide utilization.As the electron donors and acceptors were both required for caproic acid synthesis by microorganisms,in this paper,we firstly introduced the mechanism of caproic acid biosynthesis(the reverseβ-oxidation pathway)with using ethanol and acetic acid as the electron donor and acceptor,respectively.Moreover,metabolic substrates and fermentation influencing factors(temperature,pH,HRT,competitive pathways,hydrogen partial pressure,substrates ratio and nitrogen sources)were summarized.Currently,caproic acid production by Clostridium kluyveri with using ethanol as the electron donor was quite mature.Further,we explored the metabolic mechanism of caproic acid synthesis with using lactic acid as electron donor,and developing the fermentation technology of caproic acid production from lactic acid were considered as a promising direction in the future.