Abstract
The pathways of short-chain fatty acid (SCFA; acetate, propionate, and butyrate) formation from glucose were determined for the human fecal microbial communities of two subjects. The pathways were identified by radioisotope analysis of the SCFA and CO2 obtained after incubation of fecal suspensions with glucose under 20% CO2 with [1-14C]glucose, [3,4-14C]glucose, or 14CO2. Acetate was chemically degraded to learn the labeling of the methyl and carboxyl carbons. The labeling of CO2 and acetate showed that the major route of glucose catabolism was the Embden-Meyerhof-Parnas pathway, with production of CO2 from pyruvate carboxyl carbon. Labeling of the methyl and carboxyl carbons of acetate by 14CO2 or [3,4-14C]glucose proved that acetate was formed from CO2 by the Wood-Ljungdahl pathway. CO2 reduction accounted for about one-third of the acetate formed by suspensions from subject 1 and about one-fourth of the acetate formed by suspensions from subject 2. Propionate was formed by a CO2 fixation pathway, and butyrate was formed by classical routes of acetyl-S coenzyme A condensation. The amount of CO2 formed from [1-14C] glucose and acetate labeling patterns obtained with the other 14C precursors indicated that the Entner-Doudoroff, transketolase-transaldolase, and heterolactic pathways were not significant. Fermentation of cabbage cellulose by subject 1 followed the same pathways as were used for glucose. The results with suspensions from subject 2 suggested that some radioactive acetate was formed from the C-3 of glucose by the Bifidobacterium pathway.
Full Text
The Full Text of this article is available as a PDF (169.1 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Ehrlich G. G., Goerlitz D. F., Bourell J. H., Eisen G. V., Godsy E. M. Liquid chromatographic procedure for fermentation product analysis in the identification of anaerobic bacteria. Appl Environ Microbiol. 1981 Nov;42(5):878–885. doi: 10.1128/aem.42.5.878-885.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kruh J. Effects of sodium butyrate, a new pharmacological agent, on cells in culture. Mol Cell Biochem. 1982 Feb 5;42(2):65–82. doi: 10.1007/BF00222695. [DOI] [PubMed] [Google Scholar]
- Lajoie S. F., Bank S., Miller T. L., Wolin M. J. Acetate production from hydrogen and [13C]carbon dioxide by the microflora of human feces. Appl Environ Microbiol. 1988 Nov;54(11):2723–2727. doi: 10.1128/aem.54.11.2723-2727.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Miller T. L., Wolin M. J. A serum bottle modification of the Hungate technique for cultivating obligate anaerobes. Appl Microbiol. 1974 May;27(5):985–987. doi: 10.1128/am.27.5.985-987.1974. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moore W. E., Moore L. H. Intestinal floras of populations that have a high risk of colon cancer. Appl Environ Microbiol. 1995 Sep;61(9):3202–3207. doi: 10.1128/aem.61.9.3202-3207.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pavlostathis S. G., Miller T. L., Wolin M. J. Fermentation of Insoluble Cellulose by Continuous Cultures of Ruminococcus albus. Appl Environ Microbiol. 1988 Nov;54(11):2655–2659. doi: 10.1128/aem.54.11.2655-2659.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Roediger W. E. Utilization of nutrients by isolated epithelial cells of the rat colon. Gastroenterology. 1982 Aug;83(2):424–429. [PubMed] [Google Scholar]
- Royall D., Wolever T. M., Jeejeebhoy K. N. Clinical significance of colonic fermentation. Am J Gastroenterol. 1990 Oct;85(10):1307–1312. [PubMed] [Google Scholar]
- Tanaka Y., Bush K. K., Eguchi T., Ikekawa N., Taguchi T., Kobayashi Y., Higgins P. J. Effects of 1,25-dihydroxyvitamin D3 and its analogs on butyrate-induced differentiation of HT-29 human colonic carcinoma cells and on the reversal of the differentiated phenotype. Arch Biochem Biophys. 1990 Feb 1;276(2):415–423. doi: 10.1016/0003-9861(90)90740-p. [DOI] [PubMed] [Google Scholar]
- WOLFE R. S., O'KANE D. J. Cofactors of the carbon dioxide exchange reaction of Clostridium butyricum. J Biol Chem. 1955 Aug;215(2):637–643. [PubMed] [Google Scholar]
- Weaver G. A., Krause J. A., Miller T. L., Wolin M. J. Constancy of glucose and starch fermentations by two different human faecal microbial communities. Gut. 1989 Jan;30(1):19–25. doi: 10.1136/gut.30.1.19. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weaver G. A., Krause J. A., Miller T. L., Wolin M. J. Cornstarch fermentation by the colonic microbial community yields more butyrate than does cabbage fiber fermentation; cornstarch fermentation rates correlate negatively with methanogenesis. Am J Clin Nutr. 1992 Jan;55(1):70–77. doi: 10.1093/ajcn/55.1.70. [DOI] [PubMed] [Google Scholar]
- Weaver G. A., Krause J. A., Miller T. L., Wolin M. J. Incidence of methanogenic bacteria in a sigmoidoscopy population: an association of methanogenic bacteria and diverticulosis. Gut. 1986 Jun;27(6):698–704. doi: 10.1136/gut.27.6.698. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weaver G. A., Krause J. A., Miller T. L., Wolin M. J. Short chain fatty acid distributions of enema samples from a sigmoidoscopy population: an association of high acetate and low butyrate ratios with adenomatous polyps and colon cancer. Gut. 1988 Nov;29(11):1539–1543. doi: 10.1136/gut.29.11.1539. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wolever T. M., Spadafora P., Eshuis H. Interaction between colonic acetate and propionate in humans. Am J Clin Nutr. 1991 Mar;53(3):681–687. doi: 10.1093/ajcn/53.3.681. [DOI] [PubMed] [Google Scholar]
- Wolin M. J., Miller T. L. Bacterial strains from human feces that reduce CO2 to acetic acid. Appl Environ Microbiol. 1993 Nov;59(11):3551–3556. doi: 10.1128/aem.59.11.3551-3556.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]