Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 2/21/2007
Publication Date: 5/13/2007
Citation: Ashby, R.D., Solaiman, D., Foglia, T.A., Zerkowski, J.A., Marmer, W.N. 2007. Biosynthesis of Sophorolipids and Rhamnolipids from Lipid-based Substrates [abstract]. Annual Meeting and Expo of the American Oil Chemists' Society. p. 32.
Technical Abstract: Biosurfactants are surface-active molecules that are derived from living organisms. Because of their "green" origins, biosurfactants provide a number of application advantages over their synthetic counterparts, including biocompatibility, biodegradability and low toxicity. In fact, to date numerous applications are known for many biosurfactants, including applications in the pharmaceutical, cosmetic, food, agricultural and home product industries as well as in enhanced oil recovery. Presently, the major drawback to the use of biosurfactants is production costs. As such, research in our lab has concentrated on lowering production costs by utilizing low-cost agricultural feedstocks, including triacylglycerols, free fatty acids, fatty acid esters, glycerol (crude and refined) and soy molasses to fermentatively produce microbial glycolipid surfactants (sophorolipids, SL; and rhamnolipids, RL). Maximum productivities of SL (~100 g/L) were realized with the yeast, Candida bombicola, when grown in the presence of glucose and oleic acid. This SL product was made up of greater than 90% diacetylated lactones. In contrast, by using crude glycerol (biodiesel coproduct) or fatty acid esters, the lactone content of the SL decreased to 40%, thus changing the surface-active properties of the SL. In addition, we have discovered a non-pathogenic Pseudomonas strain capable of synthesizing a mono-rhamnolipid species containing dimeric hydroxy-acyl chains of 10- and 12-carbon lengths. Success in utilizing these low-cost agro-materials as substrates for high-level synthesis will reduce the production costs of the biosurfactants and provide a method to control the chemical structure and surface-active properties of the molecules.