Isolation, identification and metabolism of a Veillonella strain in human gut

Abstract:

[Objective] To isolate and identify lactate-utilizing bacteria from human gut, and investigate thier metabolic traits of lactate. [Methods] We used Hungate roll tube technique to isolate anaerobic bacteria with lactate as substrate, and then identified the strain based on morphologies, biochemical reaction and 16S rRNA gene. Then, in vitro fermentation system was used to assess the metabolic traits of lactate and its cross-feeding with lactic acid bacteria. [Results] We verified that lactate was generally utilized by human microflora. We obtained a lactate-utilizing bacterium, belonging to Veillonella, that efficiently consumed more than 50 mmol/L lactate within 24 h, and mainly generated acetate and propionate. Furthermore, it ameliorated the lactate accumulation when co-cultured with lactic acid bacteria Enterococcus. [Conclusion] Our results suggest that this strain could be used as potential probiotics with lactic acid bacteria to cooperate the dynamics of lactate in the hind gut.

Key words:Lactate-utilizing bacteria, Veillonella, Hind gut, Cross-feeding