木质纤维素沼气体系中共培养菌群形成及适应性变化研究进展

Progress in the research of coculture consortia formation and adaptation changes in biomethanation system from lignocelluloses

木质纤维素沼气化是生物能源领域最具潜力的技术之一,需要各功能菌群的协同作用和调控.本文综述了水解菌群、丙酸和丁酸互营氧化菌群以及乙酸产甲烷中各类菌群的协同效能.在水解阶段,厌氧真菌与嗜氢甲烷菌、纤维素降解菌和耗氢菌形成互利菌群后,代谢途径发生改变,实现了NAD+的再生,提高了水解效率;水解菌与非水解菌通过功能互补、抑制解除方式发挥作用.丙酸和丁酸互营氧化菌群形成后,适应性变化主要体现在种间距离缩短,电子转移加快及相关基因表达水平提高等方面.高温、高乙酸及高氨氮条件下,乙酸互营氧化产甲烷途径增强,使代谢途径更加灵活.未来菌群研究可从群体感应信号和基因水平转移两方面展开:借助调控因子,结合基因和蛋白质组学等手段深入研究群体感应信号在功能菌群形成中的作用;在菌群的适应性机理方面,通过组学分析来揭示基因水平转移在菌群适应性变化及系统进化中的意义,以便为重塑菌群结构和功能改造提供理论支持.

Biomethanation from lignocellulosic materials is one of the most promising technology in the field of biomass energy,which involves syntrophic cooperation of function microorganisms.So this paper brief ly reviews f ibrolytic consortia,propionate and butyrate oxidizing consortia by syntrophic culture and various consortia during the acetotrophic methanogenesis process.During hydrolytic stage,mutual consortia formed between anaerobic fungi and hydrogenotrophic methanogens,or cellulolytic and H2-utilizing bacteria improve the efficiency of hydrolysis by altering metabolism pathway and then regenerating NAD＋;the fibrolytic and non-fibrolytic bacteria interact with each other by ways of function complementary and disinhibition.Moreover,adaptation changes are mainly ref lected on shortened interspecific distance,accelerated interspecific electron transfer and improved expression of related gene.Under the conditions of high temperature,high concentrations of acetate and ammonia nitrogen,methanogenesis by syntrophic acetate oxidation is enhanced,making the metabolism more flexible.Future studies are carried out in the following aspects.The role of quorum sensing signal on shaping function consortia should be further studied by means of regulatory factor combined with genomics and proteomics analysis.In the aspects of adaptation mechanism,the function of horizontal gene transfer on adaptation changes and systemic evolution should be investigated,which contributes to theoretical foundation in reshaping community structure and transforming microbial function.