influence of increasing media methanol concentration on sophorolipid biosynthesis from glycerol-based feedstocks

• Published in: Biotechnology letters Vol. 32; no. 10; pp. 1429 - 1437
• Main Authors: Ashby, Richard D, Solaiman, Daniel K.Y
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.10.2010; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: alternative fuels; Applied Microbiology; Biochemistry; Biological and medical sciences; Biomass; Biomedical and Life Sciences; Biosynthesis; Biotechnology; Candida; Candida - drug effects; Candida - growth & development; Candida - metabolism; Candida bombicola; cell growth; Cellular; chemical composition; culture media; Culture Media - chemistry; Drying; fatty acid methyl esters; Fermentation; Fundamental and applied biological sciences. Psychology; glycerol; Glycerol - metabolism; glycolipids; Glycosylation; Growth media; lactones; Life Sciences; Lipid Metabolism; Media; Methanol; Methanol - metabolism; Methods. Procedures. Technologies; Methyl alcohol; Microbial engineering. Fermentation and microbial culture technology; microbial physiology; Microbiology; Oleic acid; Organisms; Original Research Paper; renewable energy sources; Separation; sophorolipid; Surface-Active Agents - metabolism; surfactants; Yeast; Candida bombicola; Crude glycerol; Fermentation; Sophorolipids; Methanol; Yeast; Glycerol; Biosynthesis; Concentration; Glycolipid; Fungi; Candida; Fungi Imperfecti
• ISSN: 0141-5492; 1573-6776
• DOI: 10.1007/s10529-010-0310-0

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.