title: Gene expression of enzymes involved in utilization of xylooligosaccharides byLactobacillusstrains.
abstract: Prebiotics are defined as food components that confer health benefits on the host through modulation of the microbiota. Xylooligosaccharides (XOS) are non-digestible oligosaccharides that have recently received increasing attention as potential prebiotic candidates. XOS are sugar oligomers composed of 1,4-linked xylopyranosyl backbone and are obtained by either chemical or, more commonly, enzymatic hydrolysis of xylan polysaccharides, extracted from the plant cell wall. The bifidogenic effect of XOS was demonstrated by both in vitro studies and small-scale in vivo human studies. Some intestinal bacterial strains are able to grow on XOS, yet numerous studies have demonstrated that the ability to utilize these oligosaccharides varies considerably among these bacteria. The aim of this study is to investigate the ability of several strainsLactobacillusto use XOS. FifteenLactobacillusstrains, allifiated toL. plantarum,L. brevisandL. sakei, were studied. Screening procedure was performed for the ability of the strains to utilize XOS as an alternative carbon source. Only some of them utilize XOS. The growth kinetics show the presence of two lag phases, indicating that these bacteria utilize probably some monosaccharides present in the used XOS. XOS were fermented with high specificity byBifidobacteriastrains, butLactobacillidid not metabolize XOS efficiently.
authors.affiliation: Faculty of Biology, Sofia University , Sofia, Bulgaria.
authors.forename: Ananieva
authors.initials: A
authors.lastname: Maria
authors.affiliation: Faculty of Biology, Sofia University , Sofia, Bulgaria.
authors.forename: Tzenova
authors.initials: T
authors.lastname: Margarita
authors.affiliation: Faculty of Biology, Plovdiv University , Plovdiv , Bulgaria.
authors.forename: Iliev
authors.initials: I
authors.lastname: IIlia
authors.affiliation: Faculty of Biology, Sofia University , Sofia, Bulgaria.
authors.forename: Ivanova
authors.initials: I
authors.lastname: Iskra
keywords: Lactobacillus; XOS; gene expression; xylooligosaccharides