title: Isolation of sophorose during sophorolipid production and studies of its stability in aqueous alkali: epimerisation of sophorose to 2-O-β-D-glucopyranosyl-D-mannose.
abstract: NMR and anion exchange chromatography analysis of the waste streams generated during the commercial production of sophorolipids by the yeast Candida bombicola identified the presence of small but significant quantities (1% w/v) of free sophorose. Sophorose, a valuable disaccharide, was isolated from the aqueous wastes using a simple extraction procedure and was purified by chromatography on a carbon celite column providing easy access to large quantities of the disaccharide. Experiments were undertaken to identify the origin of sophorose and it is likely that acetylated sophorose derivatives were produced by an enzyme catalysed hydrolysis of the glucosyl-lipid bond of sophorolipids; the acetylated sophorose derivatives then undergo hydrolysis to release the parent disaccharide. Treatment of sophorose with aqueous alkali at elevated temperatures (0.1M NaOH at 50 °C) resulted in C2-epimerisation of the terminal reducing sugar and its conversion to the corresponding 2-O-β-D-glucopyranosyl-D-mannose which was isolated and characterised. In aqueous alkaline solution β-(1,2)-linked glycosidic bonds do not undergo either hydrolysis or peeling reactions.
authors.affiliation: Department of Chemical Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom.
authors.forename: Ammar
authors.initials: A
authors.lastname: Al-Jasim
authors.affiliation: Department of Chemical Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom.
authors.forename: Mark
authors.initials: M
authors.lastname: Davis
authors.affiliation: Croda Biotechnology, Foundary Lane, Ditton, Widnes, Cheshire WA8 8UB, United Kingdom.
authors.forename: Douglas
authors.initials: D
authors.lastname: Cossar
authors.affiliation: Croda Biotechnology, Foundary Lane, Ditton, Widnes, Cheshire WA8 8UB, United Kingdom.
authors.forename: Timothy
authors.initials: T
authors.lastname: Miller
authors.affiliation: Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Humphreys
authors.affiliation: Department of Chemical Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom. Electronic address: a.p.laws@hud.ac.uk.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Laws
mesh_terms: D000107:Acetylation; D002852:Chromatography, Ion Exchange; D005936:Glucans / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008055:Lipids / Q000096:biosynthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000737:chemistry / Q000302:isolation & purification*; D015394:Molecular Structure; D062065:Wastewater / Q000737:chemistry*
chemical_list: D005936:Glucans; D008055:Lipids; D008358:Mannose; D062065:Wastewater; C003328:sophorose
keywords: 2-O-β-d-glucopyranosyl-d-mannose; Sophorolipids; Sophorose; β-(1,2)-linked disaccharides