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

Abstract:

[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.