Kinetics of monoglyceride synthesis catalyzed by a monoacylglycerol lipase (MGL) isolated from Pseudomonas sp. LP7315 was studied at 65 degreesC in a solvent-free two-phase system, in which fatty acid droplets were dispersed in a glycerol phase containing a small amount of water. The initial rate of the synthetic reaction depended on several factors: the amounts of fatty acid and glycerol, and the concentration of MGL in the glycerol phase. To analyze the effects of these factors, a kinetic model was developed based on the assumption that the adsorption equilibrium of MGL molecules at the interface between the two phases is the crucial factor For the synthetic reaction. The model was found to yield good approximations of the initial synthetic rate under various reaction conditions. The analysis suggests that the adsorption behavior of MGL onto the interface had a large effect on the initial rate of the monoglyceride synthesis.