窖泥优势拟杆菌纲微生物Petrimonas sulfuriphila的分离及其功能解析

目的]筛选窖泥中尚未被纯培养的高丰度拟杆菌纲微生物,并在纯培养菌株层面和共培养层面探究其生理代谢特征及生态学功能。方法]采用传代培养提高窖泥拟杆菌纲微生物的相对丰度,在此基础上进行筛菌实验,并通过发酵实验解析主体拟杆菌的代谢特征及其与主体己酸菌的相互作用关系。结果]成功筛选到Petrimonas sulfuriphila LBM11005,该菌的主要代谢产物为乙酸和丙酸,且葡萄糖能促进该菌的生长。无论是否存在底物竞争效应,P. sulfuriphila LBM11005均能与窖泥主体己酸菌Caproicibacterium sp. LBM19010在代谢物水平上发生相互作用,表现为后者可以利用前者的代谢产物丙酸进行碳链延伸,产生新的奇数碳脂肪酸——戊酸和庚酸。结论]探明了窖泥主体拟杆菌纲微生物P. sulfuriphila LBM11005的基本生理代谢特征,且该菌与主体己酸菌相互作用,贡献于更长碳链奇数碳脂肪酸的合成。

Isolation and functional analysis of the dominant Bacteroidia species Petrimonas sulfuriphila in pit mud

Objective]To isolate abundant uncultured Bacteroidia species from pit mud and analyze its physiological metabolism and ecological functions in the cases of pure culture and co-culture.Methods] The relative abundance of Bacteroidia species was improved by subculture.Pure Bacteroidia species were isolated with the agar dilution method,and the metabolic characteristics of the dominant Bacteroidia species and the interaction with the dominant caproate-producing bacteria were explored based on fermentation test.Results] Petrimonas sulfuriphila LBM11005 was screened out.Acetate and propionate were the main metabolites of this strain,and glucose promoted its growth.The metabolites ofLBM11005 interacted with those of Caproicibacterium sp.LBM19010,the dominant caproate-producing species in pit mud,regardless of substrate competition.To be specific,LBM19010 utilized propionate,the metabolite of LBM11005,for chain extension to produce odd-numbered carbon fatty acids of pentanoate and heptanoate.Conclusion] This study reveals the fundamental physiological and metabolic characteristics of P.sulfuriphila LBM11005,one of the dominant Bacteroidia species in pit mud.This strain interacts with the dominant caproate-producing bacterium to contribute to the synthesis of longer odd-numbered carbon fatty acids.