title: Modification of colonic fermentation by bifidobacteria and pH in vitro. Impact on lactose metabolism, short-chain fatty acid, and lactate production.
abstract: Colonic fermentation plays an important role in the prevention of lactose intolerance and intestinal disorders. The objectives of this study were to evaluate whether supplementation with bifidobacteria modify colonic fermentation of lactose and short-chain fatty acid production and to assess influence of the pH in an in vitro continuous culture system. There was a significantly greater reduction in lactose concentrations at pH 6.7 than that at either pH 6.2 or pH 5.7, accompanied by the highest beta-galactosidase activity and D-lactate production. Bifidus supplementation reduced lactose and D-lactate concentrations and increased acetate production at pH 6.7. The study demonstrates that lactose is rapidly metabolized by colonic bacteria and lactose fermentation in vitro is pH dependent with a maximum rate at pH 6.7. Bifidobacteria supplementation may have the potential to improve lactose fermentation and to manipulate SCFA and lactate production.
authors.affiliation: Department of Pediatrics, University of Iowa Hospitals and Clinics, Iowa City 52242, USA.
authors.forename: T
authors.initials: T
authors.lastname: Jiang
authors.forename: D A
authors.initials: DA
authors.lastname: Savaiano
mesh_terms: D000328:Adult; D001644:Bifidobacterium / Q000378:metabolism*; D003106:Colon / Q000378:metabolism / Q000382:microbiology*; D004063:Digestion / Q000502:physiology; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D005243:Feces / Q000737:chemistry; D005285:Fermentation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D019344:Lactic Acid / Q000096:biosynthesis; D007785:Lactose / Q000378:metabolism*; D008297:Male
chemical_list: D005232:Fatty Acids, Volatile; D019344:Lactic Acid; D007785:Lactose