Rates of production and utilization of lactate by microbial communities from the human colon

Alvaro Belenguer, Grietje Holtrop, Sylvia H. Duncan, Susan E. Anderson, A. Graham Calder, Harry J. Flint, Gerald E. Lobley

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Lactate metabolism was studied in mixed bacterial communities using single-stage continuous flow fermentors inoculated with faecal slurries from four different volunteers and run for 6 days at pH 5.5 and 6.0, using carbohydrates, mainly starch, as substrates. A continuous infusion of [U-13C]starch and l-[3-13C]lactate was performed on day 5 and a bolus injection of l-[3-13C]lactate plus dl-lactate on day 6. Short-chain fatty acids and lactate concentrations plus enrichments and numbers of lactate-producing and -utilizing bacteria on day 5 were measured. Faecal samples were also collected weekly over a 3-month period to inoculate 24-h batch culture incubation at pH 5.9 and 6.5 with carbohydrates alone or with 35 mmol L-1 lactate. In the fermentors, the potential lactate disposal rates were more than double the formation rates, and lactate concentrations usually remained below detection. Lactate formation was greater (P < 0.05) at the lower pH, with a similar tendency for utilization. Up to 20% of butyrate production was derived from lactate. In batch cultures, lactate was also efficiently used at both pH values, especially at 6.5, although volunteer and temporal variability existed. Under healthy gut environmental conditions, bacterial lactate disposal seems to exceed production markedly.

Original languageEnglish
Pages (from-to)107-119
Number of pages13
JournalFEMS Microbiology Ecology
Volume77
Issue number1
Early online date6 Apr 2011
DOIs
Publication statusPublished - Jul 2011

Keywords

  • colonic bacteria
  • human health
  • lactate metabolism
  • stable isotope
  • butyrate-producing bacteria
  • continuous culture system
  • human fecal bacteria
  • resistant starch
  • human feces
  • human gut
  • fermentation products
  • ulcerative colitis
  • PH
  • metabolism

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