Extraction, separation and characterization of lipopeptides and phospholipids from corn steep water

Abstract

This is the first work about the fractionation, separation and identification of different bioactive compounds contained in a multifunctional biosurfactant extract, obtained from corn steep water through a liquid–liquid extraction with chloroform. In this extract, phospholipids (21%) were precipitated with acetone and identified by electrospray ionization mass spectrometry (ESI-MS/CID), detecting a characteristic signal at 758 m/z that corresponds with phosphatidylethanolamine and phosphatidylcholine. In this extract, major biomarkers at 879 and 933 m/z and small signals between 1000 and 1500 m/z were also detected, corresponding with lipopeptides (25%) with different molecular weights. For determining the amino acids and fatty acids of these lipopeptides, the biosurfactant extract, obtained from corn steep water, was subjected to acid hydrolysis. Subsequent, the fatty acids contained in the hydrolysate were extracted with ether and analyzed by gas chromatography–mass spectrometry (CG-MS), discovering the presence of C16 and C18 fatty acids. Additionally, the hydrolyzed peptides, solubilized in the aqueous phase, were analized using ESI-MS/MS/CID, identifying glutamic acid/glutamine, aspartic acid/asparagine, glycine, alanine, arginine, proline and leucine/isoleucine. Free fatty acids (49.1%) were also quantified by titration with KOH. Remarkably, all the compounds identified in this multifunctional biosurfactant have high interest for obtaining more compatible formulations in different industries.