title: The influence of increasing media methanol concentration on sophorolipid biosynthesis from glycerol-based feedstocks.
abstract: Candida bombicola, a known producer of sophorolipids (SLs; glycolipid surfactants), was grown on glycerol and oleic acid with up to 1.5% (v/v) methanol in the fermentation growth media to assess the effects of methanol presence on SL synthesis and structural distribution. Increasing methanol concentrations had little effect on the growth of the organism resulting in average cell dry weights (CDW; after SL separation) of 20.8 ± 0.7 g/l between 0 and 1.5% methanol. However, increasing methanol concentrations decreased SL production by 56% (from 12.7 to 5.6 g/l at 1.5% methanol) which translated to SL yields on a cellular basis of between 0.60 g SL/g cells (in the absence of methanol) to 0.27 g SL/g cells (in the presence of 1.5% methanol). LC/MS revealed that increased methanol concentrations also resulted in larger concentrations (up to 20 mol%) of free acid SLs but had little effect on the ratios of diacetylated SL lactones synthesized with palmitic acid (4 mol%), linoleic acid (3 mol%), oleic acid (80 mol%), and stearic acid (13 mol%) as the hydrophobic moieties.
authors.affiliation: US Department of Agriculture, Fats, Oils and Animal Coproducts Research Unit, Agricultural Research Service, Eastern Regional Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038, USA. Rick.Ashby@ars.usda.gov
authors.forename: Richard D
authors.initials: RD
authors.lastname: Ashby
authors.forename: Daniel K Y
authors.initials: DK
authors.lastname: Solaiman
mesh_terms: D018533:Biomass; D002175:Candida / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D005990:Glycerol / Q000378:metabolism*; D050356:Lipid Metabolism; D000432:Methanol / Q000378:metabolism*; D013501:Surface-Active Agents / Q000378:metabolism*
chemical_list: D003470:Culture Media; D013501:Surface-Active Agents; D005990:Glycerol; D000432:Methanol