生物滴滤塔共代谢降解间二甲苯的性能及微生物群落分析

Performance and microbial evolution of m-xylene co-metabolic biodegradation in a biotrickling filter

为发挥混合污染物之间的协同作用,引入甲苯,与间二甲苯形成共代谢降解体系,从而促进间二甲苯的生物降解性能,对比分析了二者在不同质量浓度配比下的相互作用关系,以及反应器内微生物群落结构和功能变化。甲苯进气质量浓度约为250 mg/m^(3),甲苯与间二甲苯进气质量浓度比分别为1∶1、1∶2、1∶4和1∶6。结果表明,当二者质量浓度比例为1∶1、1∶2和1∶4时,甲苯能够作为生长基质,促进微生物生长与积累,提高生物滴滤反应器内物种丰度及代谢活性,产生共代谢作用,质量浓度比例为1∶2时共代谢作用最明显。二者质量浓度比例为1∶6时,结果正相反,甲苯抑制间二甲苯的生物降解。在整个生物降解过程中,变形菌门均为第一优势菌门。产生共代谢作用时,伯克氏菌属和分枝杆菌属的丰度增加,尤其是伯克氏菌属占比从7.11%最高增加到21.94%。基因代谢功能预测结果表明,一级代谢通路中的新陈代谢和二级代谢子功能中的氨基酸代谢等基因丰度的增加促进共代谢作用的产生。

To construct a co-metabolic system and enhance the biodegradation of m-xylene in a biotrickling filter,the interaction between m-xylene and toluene under varying mixing ratios was explored.The performance and microbial community structure and function were analyzed in this study.The inlet concentration of toluene was maintained at about 250 mg/m^(3),and the ratios of toluene and m-xylene were 1∶1,1∶2,1∶4,and 1∶6.The results indicated that compared with the performance of single m-xylene removal,the biodegradation was improved when toluene and m-xylene were mixed with the ratios of 1∶1,1∶2,and 1∶4,especially when the radio was 1∶2,the removal efficiency(RE)of m-xylene was increased from 87.22%to 96.61%,and biodegradation was inhibited when the ratio was 1:6.The changes in biomass showed that toluene was used as a growth substrate,providing carbon and energy sources for microorganisms,promoting the growth of microorganisms and the formation of biofilms,and thus stimulating the generation of microbial co-metabolism.In the process of co-metabolism,the abundance of microorganisms was increased and the microbial degradation ability was improved.In the whole biodegradation process,bacteria played an important role and Proteobacteria were the most dominant phylum,which was capable of efficiently removing m-xylene and toluene.At the genus level of bacteria,the abundance of Burkholderia and Mycobacterium increased during co-metabolism,especially Burkholderia increased from 7.11%to 21.94%.The PICRUSt(Phylogenetic Investigation of Communities by Reconstruction of Unobserved States)showed that among the primary metabolic pathways,the functional genes of Metabolism accounted for more than 50%and increased rapidly during the co-metabolism process,ranking second with a growth rate of 19.86%.Among the secondary metabolic pathways,the functional genes of Amino Acid Metabolism accounted for the largest proportion,followed by Carbohydrate Metabolism,and Xenobiotics Biodegradation and Metabolism,which were favorable for co-metabolic biodegradation of m-xylene.