title: Synthesis of prebiotic galactooligosaccharides using whole cells of a novel strain, Bifidobacterium bifidum NCIMB 41171.
abstract: A novel strain of Bifidobacterium bifidum NCIMB 41171, isolated from a faecal sample from a healthy human volunteer and able to express beta-galactosidase activity, was used in synthesis reactions for the production of galactooligosaccharide from lactose. The beta-galactosidase activity of whole bifidobacterial cells showed an optimum activity at pH 6.8-7.0 and 40 degrees C. The transgalactosylation activity of the B. bifidum cells from 50% (w/w) lactose resulted in a galactooligosaccharide mixture (20% w/w) comprising (w/w): 25% disaccharides, 35% trisaccharides, 25% tetrasaccharides and 15% pentasaccharides. Using different initial lactose concentrations, the conversion rate to galactooligosaccharides was maximum (35%) when 55% (w/w) lactose was used. In fermentation experiments, B. bifidum showed an increased preference towards the produced galactooligosaccharide mixture, displaying higher growth rate and short-chain fatty acid production when compared with commercially available oligosaccharides.
authors.affiliation: School of Food Biosciences, The University of Reading, Whiteknights, UK. G.Tzortzis@reading.ac.uk
authors.forename: George
authors.initials: G
authors.lastname: Tzortzis
authors.forename: Athanasios K
authors.initials: AK
authors.lastname: Goulas
authors.forename: Glenn R
authors.initials: GR
authors.lastname: Gibson
mesh_terms: D001644:Bifidobacterium / Q000201:enzymology* / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005260:Female; D005285:Fermentation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007785:Lactose / Q000378:metabolism; D009844:Oligosaccharides / Q000096:biosynthesis / Q000378:metabolism*; D013696:Temperature; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D009844:Oligosaccharides; D001616:beta-Galactosidase; D007785:Lactose