CONTROL OF LIPASE-MEDIATED GLYCEROLYSIS REACTIONS WITH BUTTEROIL IN DUAL LIQUID-PHASE MEDIA DEVOID OF ORGANIC-SOLVENT

Factors affecting the progress of glycerolysis reactions with butteroil mediated by two lipase preparations (from Pseudomonas sp.) in dual liquid phase mixtures devoid of solvent were evaluated. Within the range of parameters evaluated, the conditions best supporting the formation of monoacylglycerols (MAG) were 35-degrees-C, 2.5-4.8% water in glycerol, and 0.33-0.44 g of glycerol/g of butteroil (equivalent to a molar ratio of acyl groups to glycerol of 0.66-0.85). Under these conditions, percent yields of MAG formation from butteroil were 50-55% (mass fraction) relative to the other acylglycerol species and fatty acids accumulated. Little interaction was observed between these critical parameters. At temperatures greater than 35-degrees-C, up to a 50 % reduction in yield of MAG was noted. Temperature shift experiments indicated that MAG and other acylglycerol components were interconvertible. Incubation of reactive mixtures at 35-degrees-C after a prior incubation at 52-degrees-C restored the yield of MAG from about 25% to the near-maximal levels of 50-55 %. The effect of this temperature shift was manifest as a net and reversible interconversion of MAG and 1,3-DAG, and changes in other acylglycerol components did not take place. Temperature control of reaction equilibria was not attributable to changes in availability of water.