CONTROL OF LIPASE-MEDIATED GLYCEROLYSIS REACTIONS WITH BUTTEROIL IN SINGLE LIQUID-PHASE MEDIA WITH 2-METHYL-2-PROPANOL

Factors affecting the progress of glycerolysis reactions with butteroi l mediated by two lipase preparations (from Pseudomonas sp.) in single liquid phase mixtures containing 2-methyl-2-propanol were evaluated. Within the range of parameters evaluated, the conditions best supporti ng the formation of monoacylglycerols (MAG) were 25-40% butteroil subs trate, 10-20 mg of enzyme/mL of substrate mixture, 35-degrees-C, and 1 00-150 mg of glycerol/mL of substrate mixture (equivalent to a molar r atio of fatty acyl groups to glycerol of 0.61-0.76). Under these condi tions, the percent yield of MAG formation from butteroil was 50-60 % ( mass fraction) relative to the other acylglycerol species and fatty ac ids accumulated. These conditions were somewhat dependent on the sourc e of enzyme and probably related to the water content of the enzyme re agents. At temperatures greater than 35-degrees-C, and at the greatest levels of glycerol (150 mg/mL) used, a severe restriction of activity was noted, particularly for the lipase preparation with the lesser wa ter content. However, activity and percent yields of MAG could be rest ored to near-optimal levels by the simple addition of water of up to 1 % of the reaction volume. The ability of the chosen lipases to mediat e glycerolysis reactions with butteroil, and other oils, appears to be principally controlled by water availability in the reaction mixture.