Enzymatic strategies for solvent-free production of short and medium chain phytosteryl esters

Transesterification of phytosterols with short and medium chain fatty acids (MCFAs) ethyl esters and with tributyrin catalyzed by Candida rugosa and Pseudomonas stutzeri TL lipases in solvent-free medium was studied including the effects of temperature, fatty acid specificity, enzyme quantity, the residual activity of each lipase and reduced pressure. More than the 90% of the original phytosterols were transformed into their corresponding phystosteryl esters after 3-4h reaction at 50-60°C and at 100-350mbar. The product mixtures containing 40-50% (w/w) phystosteryl esters were then vacuum distilled to remove molar excess of SCFA and MCFA ethyl esters utilized in the enzymatic reaction. By this methodology, purities >95% in short and medium chain phytosteryl esters were finally obtained. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Funded by: Comunidad Autónoma de Madrid (ALIBIRD. Grant Number: S2009/AGR-1469 and Consolider-Ingenio FUN-C-FOOD. Grant Number: CSD2007-00063.Peer Reviewe