碳材料增强微生物种间电子传递强化餐厨垃圾厌氧消化产甲烷研究综述

Enhanced anaerobic digestion of food waste by carbon materials via mediating microorganisms interspecific electron transport

餐厨垃圾厌氧消化产甲烷是餐厨垃圾资源化、能源化利用的重要途径,但其有机物互营产甲烷过程易受微生物间接种间电子传递的低速瓶颈和低氢分压限制的影响,导致有机酸累积抑制、甲烷回收效率低,系统稳定性差。近年来大量研究表明,多种导电碳材料可通过介导互营微生物直接种间电子传递(DIET),大幅提高种间电子传递速率,并突破低氢分压限制,强化餐厨垃圾厌氧产甲烷。文章在梳理有机物厌氧消化微生物种间电子传递机理的基础上,总结了活性炭、生物炭、碳布、石墨等多种导电碳材料介导微生物DIET强化餐厨垃圾厌氧消化的最新研究进展,包括碳材料对互营细菌和产甲烷菌种间电子传递、产气滞后期及甲烷产量、有机酸代谢和系统稳定性、厌氧微生物群落结构动态演化的影响。尽管外源碳材料介导DIET强化餐厨垃圾厌氧消化的优异效果已被证实,但碳材料诱导互营微生物间DIET体系建立的机理尚未明确,而且碳材料如何在大型沼气工程中持续稳定发挥功效及其回收利用问题仍未有效解决。在未来的研究中,碳材料诱导下高效DIET功能菌群的构建机制及其工程化应用将是重点研究方向。

Currently,anaerobic digestion is the main way of energy recovery from food waste.However,in practice,volatile fatty acids(VFAs)syntrophic metabolism involved in anaerobic digestion of food waste is susceptible to the low-speed bottleneck of indirect interspecific electron transport between syntrophic community and the limitation of low hydrogen partial pressure,which will lead to VFAs inhibition,low methane recovery efficiency and poor process stability.Many previous researches reported that multiple conductive carbon materials could significantly enhance methane production from anaerobic digestion of food waste by improving interspecific electron transfer rate between syntrophic community via mediating direct interspecific electron transfer(DIET).This study summarized the mechanism of interspecific electron transfer between syntrophic community during anaerobic digestion and reviewed latest research progress concerning typical conductive carbon materials(activated carbon,biochar,carbon cloth,graphite,etc.)enhanced anaerobic digestion of food waste by mediating DIET focusing on effects of carbon materials on interspecific electron transfer between syntrophic community,lag phase of methane production and methane yield,VFAs conversion and anaerobic system stability,anaerobic microbial community dynamics,etc.The positive effects of carbon materials on anaerobic digestion of food waste in mediating DIET has been often reported,but the mechanism that carbon materials inducing the establishment of DIET system between syntrophic community is still not clear.Meanwhile,how carbon materials maintain stable efficacy in the large-scale biogas plant and the recycling problem are still not effectively solved.In the future,the mechanism of carbon materials inducing high-efficiency DIET functional communities and the large-scale engineering application of carbon material additives will be the key research directions.