title: Lactobacillus reuteri Strains Convert Starch and Maltodextrins into Homoexopolysaccharides Using an Extracellular and Cell-Associated 4,6-α-Glucanotransferase.
abstract: Exopolysaccharides (EPS) of lactic acid bacteria (LAB) are of interest for food applications. LAB are well-known to produce α-glucan from sucrose by extracellular glucansucrases. Various Lactobacillus reuteri strains also possess 4,6-α-glucanotransferase (4,6-α-GTase) enzymes. Purified 4,6-α-GTases (e.g., GtfB) were shown to act on starches (hydrolysates), cleaving α1→4 linkages and synthesizing α1→6 linkages, yielding isomalto-/maltopolysaccharides (IMMP). Here we report that also L. reuteri cells with these extracellular, cell-associated 4,6-α-GTases synthesize EPS (α-glucan) from starches (hydrolysates). NMR, SEC, and enzymatic hydrolysis of EPS synthesized by L. reuteri 121 cells showed that these have similar linkage specificities but generally are much bigger in size than IMMP produced by the GtfB enzyme. Various IMMP-like EPS are efficiently used as growth substrates by probiotic Bifidobacterium strains that possess amylopullulanase activity. IMMP-like EPS thus have potential prebiotic activity and may contribute to the application of probiotic L. reuteri strains grown on maltodextrins or starches as synbiotics.
authors.affiliation: Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen , Nijenborgh 7, 9747 AG Groningen, The Netherlands.|The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University , Wuxi 214122, China.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen , Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors.forename: Markus
authors.initials: M
authors.lastname: Böger
authors.affiliation: Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen , Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors.forename: Rachel Maria
authors.initials: RM
authors.lastname: van der Kaaij
authors.affiliation: Department of Polymer Chemistry, Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Albert Jan Jacob
authors.initials: AJ
authors.lastname: Woortman
authors.affiliation: Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen , Groningen, The Netherlands.
authors.forename: Tjaard
authors.initials: T
authors.lastname: Pijning
authors.affiliation: Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen , Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors.forename: Sander Sebastiaan
authors.initials: SS
authors.lastname: van Leeuwen
authors.affiliation: Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen , Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors.forename: Alicia Lammerts
authors.initials: AL
authors.lastname: van Bueren
authors.affiliation: Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen , Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors.forename: Lubbert
authors.initials: L
authors.lastname: Dijkhuizen
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D055162:Biocatalysis; D001711:Biotransformation; D006004:Glycogen Debranching Enzyme System / Q000737:chemistry / Q000378:metabolism*; D052200:Limosilactobacillus reuteri / Q000201:enzymology* / Q000378:metabolism; D015394:Molecular Structure; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D013213:Starch / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D006004:Glycogen Debranching Enzyme System; D011134:Polysaccharides; C008315:maltodextrin; D013213:Starch; C020569:4 alpha-glucanotransferase
keywords: 4,6-α-glucanotransferase; Lactobacillus reuteri; exopolysaccharides; starch; synbiotics