The use of fatty acid esters to enhance free acid sophorolipid synthesis.
Fatty acid esters were prepared by transesterification of soy oil with methanol (methyl-soyate, Me-Soy), ethanol (ethyl-soyate, Et-Soy) and propanol (propyl-soyate, Pro-Soy) and used with glycerol as fermentation substrates to enhance production of free-acid sophorolipids (SLs). Fed-batch fermentations of Candida bombicola resulted in SL yields of 46 +/- 4 g/l, 42 +/- 7 g/l and 18 +/- 6 g/l from Me-Soy, Et-Soy, and Pro-Soy, respectively. Liquid chromatography with atmospheric pressure ionization mass spectrometry (LC/API-MS) showed that Me-Soy resulted in 71% open-chain SLs with 59% of those molecules remaining esterified at the carboxyl end of the fatty acids. Et-Soy and Pro-Soy resulted in 43% and 80% open-chain free-acid SLs, respectively (containing linoleic acid and oleic acid as the principal fatty acid species linked to the sophorose sugar at the omega-1 position), with no evidence of residual esterification.
Ashby
Richard D
RD
Fats, Oils and Animal Coproducts Research Unit, US Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA. rashby@errc.ars.usda.gov
Solaiman
Daniel K Y
DK
Foglia
Thomas A
TA
D000438:Alcohols / Q000737:chemistry*; D002175:Candida / Q000145:classification / Q000378:metabolism*; D018929:Cell Culture Techniques / Q000379:methods*; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008055:Lipids / Q000096:biosynthesis* / Q000737:chemistry; D013024:Soybean Oil / Q000737:chemistry*; D013045:Species Specificity
D000438:Alcohols; D003470:Culture Media; D005227:Fatty Acids; D008055:Lipids; D013024:Soybean Oil