Production of Glyceryl Monostearate by Immobilized Candida Antarctica B Lipase in Organic Media

Abstract

Chemical methods of synthesizing monoglycerides (MGs) produce mixture of acylglycerols making the synthesis of MGs of a single fatty acid type not possible through this route. Lipases due to their selectivity and specificity offer a useful way of synthesizing highly purified single fatty acid containing monoglycerides. Glyceryl monostearate (GMS), a nonionic amphiphilic monoglyceride of glycerol and stearic acid is widely used as emulsifier in food, cosmetic, pharmaceutical and textile industry. In the present work, lipase mediated synthesis of GMS was explored using Novozym 435 and indigenously immobilized Candida antarctica B lipase. Direct esterification of glycerol and stearic acid was used as strategy and various parameters that influence synthesis of glyceryl monostearate such as molar ratio of substrates, enzyme load, reaction time and solvent polarity were systematically studied using Novozym 435 lipase. Esterification efficiency of indigenously immobilized Candida antarctica B lipase and Novozym 435 was compared for synthesis of GMS and indigenously immobilized Candida antarctica B lipase gave conversion competitive to Novozym 435. Indigenously immobilized Candida antarctica B lipase in the presence of homogenous substrate solution using tert-butyl alcohol as the reaction medium, resulted in exclusive production of monoglyceride without formation of diglyceride. Continuous production of GMS was also carried out in packed bed reactor and 94% conversion of stearic acid was achieved.