Continuous enzymatic esterification of glycerol with (poly)unsaturated fatty acids in a packed-bed reactor

Enzymatic synthesis of mono-, di-, and triacyglycerols from (poly)unsaturat ed fatty acids (linoleic, oleic, and conjugated linoleic acids) has been st udied as a solvent-free reaction in a packed-bed reactor containing an immo bilized lipase from Mucor miehei The extents of the esterification reaction s of interest are primarily determined by the molar ratio of glycerol to fa tty acid because the presence of excess glycerol as a immiscible phase is r esponsible for reducing the activity of the water produced by the esterific ation reactions. For molar ratios of fatty acid to glycerol of less than 1. 5, the percentage of the fatty acid esterified decreases quasi-linearly wit h an increase in this molar ratio. By appropriate manipulation of the fluid-residence time, one can control th e relative proportions of the various acylglycerols in the effluent stream. At the outlet of the reactor, one observes excellent spontaneous separatio n of the glycerol and acylglycerol/fatty acid phases. At 50 degrees C and a fluid residence time of 1 hour, as much as 90% of the fatty acid can be es terified when the molar ratio of fatty acid to glycerol is 0.33 or less. (C ) 2000 John Wiley & Sons, Inc.