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.
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
Richard D
RD
Ashby
Daniel K Y
DK
Solaiman
Thomas A
TA
Foglia
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