Methods of producing compositions comprising hydrophilic sophorolipids
The subject invention provides materials and methods for producing high-HLB sophorolipid-based compositions and/or for increasing the water solubility of sophorolipid compositions. More specifically, the subject invention provides for the production and post-fermentation alteration of SLP molecules, which can be used for formulating a variety of useful compositions.
1 . A method for producing a sophorolipid composition with an HLB of 9 or greater, the method comprising:
obtaining a yeast fermentation product comprising a mixture of hydrophilic SLP molecules comprising non-acetylated linear SLP, and hydrophobic SLP molecules comprising lactonic SLP and mono-and di-acetylated linear SLP, said mixture being produced by cultivating a SLP-producing microorganism;
functionalizing the hydrophobic SLP molecules by converting them into hydrophilic molecules to produce a hydrophilic SLP fraction comprising only hydrophilic SLP molecules, wherein the hydrophobic SLP molecules are converted to hydrophilic SLP molecules by mixing the hydrophobic SLP molecules with a base;
producing a purified hydrophobic SLP fraction; and
mixing the hydrophilic SLP fraction with the purified hydrophobic SLP fraction at a ratio of hydrophilic SLP molecules to purified hydrophobic SLP molecules between 60:40 to 75:25.
2 . The method of claim 1 , wherein producing the purified hydrophobic SLP fraction comprises allowing a second yeast fermentation product to sit undisturbed for 12 to 24 hours, wherein a layer substantially comprising hydrophobic SLP molecules settles to the bottom of the second yeast fermentation product,
wherein the settled layer is harvested to obtain a crude hydrophobic SLP fraction comprising residual yeast cells, glucose, fatty acids, and/or fermentation broth, in addition to the hydrophobic SLP molecules, and
the crude hydrophobic SLP fraction is treated to remove the residual yeast cells, glucose, fatty acids, and/or fermentation broth, thereby producing the purified hydrophobic SLP fraction.
3 . The method of claim 1 , wherein the SLP-producing microorganism is Starmerella bombicola.
4 . The method of claim 1 , wherein converting the hydrophobic SLP molecules into hydrophilic SLP molecules modifies a functional property of the sophorolipid composition selected from HLB, solubility, foaming, detergency, emulsification, demulsification, and wettability alteration.
5 . The method of claim 4 , wherein the functional property is HLB.
6 . The method of claim 4 , wherein the functional property is water solubility, and wherein the water solubility is increased.
7 . The method of claim 1 , wherein the base facilitates alkali-mediated l actone bond breakage of lactonic SLP molecules and/or alkali-mediated deacetylation of lactonic and/or linear SLP molecules.
8 . The method of claim 4 , wherein the water solubility of the hydrophobic SLP fraction is increased by mixing the fraction with an organic amine selected from ethanolamine, triethanolamine, propylamine, and isopropylamine.