Submitted to: American Oil Chemists' Society Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2004
Publication Date: 10/11/2004
Citation: Ashby, R.D., Nunez, A., Solaiman, D., Foglia, T.A. 2004. Production and structural variability of sophorolipids derived from the fermentation of renewable resources [abstract]. American Oil Chemists' Society Meeting. p. 29.
Technical Abstract: Sophorolipids (SL) are extracellular glycolipids produced by a number of Candida species through fermentation of renewable resources. They consist of a disaccharide, sophorose (2-O-beta-D-glucopyranosyl-beta-D-glucopyranose) bound to a hydroxy fatty acid moiety through the omega-1 or omega carbon. The fatty acid (FA) can be free or lactonized to carbon 4' of the disaccharide. These molecules have been applied as bio-based surfactants and as additives in the cosmetic and lubricant industries. Candida bombicola is the most studied organism for SL production due to its high productivity. Whether derived from glucose alone or from a co-feeding strategy with triacylglycerols (TAGs) or FAs, SL yields from C. bombicola exceeded 50 g/L in batch culture and in some instances reached close to 100 g/L. The structural variability of the SL was dictated by the lipidic co-substrate. Liquid Chromatography (LC) with Atmospheric Pressure Chemical Ionization - Mass Spectrometry (APCI-MS) revealed that FAs of carbon chain length 16 and/or 18 were present in all SLs with C18:1delta9 (omega-1 linkage) predominating in a lactonic conformation. The FA chain length and degree of unsaturation was conferred by the content of the TAG or FA. In addition, we showed that glycerol is a viable substrate for SL synthesis resulting in 99% lactonic SL. However, the use of crude glycerol (derived from biodiesel production) resulted in the production of SLs in predominantly free acid and methyl ester form (75%, vs 25% in lactonic form) in good yield (~60 g/L). Recently, we explored the use of fats, oils and their derivatives as substrates for the synthesis of SL containing a C22:0 FA by Rhodotorula bogoriensis. The production of large quantities of SL and the capability to control their molecular structure will provide an economically feasible production process, an additional outlet for renewable resources and new targeted applications for these molecules.