Short chain fatty acid esters synthesis by commercial lipases in low-watersystems and by resting microbial cells in aqueous medium

Thirteen commercial lipases in hexane and seventeen bacterial cell suspensi ons in aqueous media were screened for the production of ethyl valerate and ethyl butyrate. The highest esterifying activity was obtained with commerc ial Pancrealipase (Biozymes Inc.) and Candida rugosa lipase (Amano Enzyme L td) and with bacterial cell suspension from Pseudomonas fragi CRDA 446. Com mercial enzymes gave molar conversion yield of 68% over 24 h as compared to 17% with whole cells in aqueous medium. However, a comparison of both sour ces of biocatalyst i.e. whole microbial cells and commercial lipases, based on the amount of ester produced per g of protein for a complete reaction, indicated similar activities.