Development of an integrated process involving palm industry co-products for monoglyceride/diglyceride emulsifier synthesis: Use of palm cake and fiber for lipase production and palm fatty-acid distillate as raw material

Abstract

In the present study, monoglycerides (MAG) and diglycerides (DAG) were produced by an enzymatic esterification reaction of palm fatty-acid distillate (PFAD) (co-product) with glycerol, using a dry fermented solid (DFS) with lipase activity obtained by solid-state fermentation in palm cake and fiber (co-products) in an integrated process. The reaction using DFS as biocatalyst was optimized by a central composite rotatable design. MAG and DAG yields of 25% and 40% were obtained, respectively, in a reaction with molar ratio of 2:1 (glycerol: PFAD), 9.6 wt% water content, and 20 wt% DFS at 50 °C after 48 h. MAG and DAG synthesis using the commercial biocatalyst Lipozyme® RM-IM (immobilized lipase from Rhizomucor miehei) was also evaluated. The highest MAG and DAG yields in reactions with Lipozyme RM-IM were attained in a molar ratio of 1:1 (glycerol: PFAD), 3 wt% enzyme at 50 °C after 10 h (MAG and DAG yields of 27.9% and 53.05%, respectively). Results obtained with DFS and Lipozyme RM-IM were close to the WHO (World Health Organization) guidelines, in which these mixtures must contain at least 70% MAG + DAG and a minimum of 30% MAG.