A biodegradable polyester resin was polymerized from N-benzyloxycarbonyl-L-glutamic acid and ethylene glycol. Rhizopus delemar lipase was used as a biocatalyst for the rupture of ester bonds during the hydrolysis studies. Depolymerization was observed to follow a Michaelis-Menten mechanism, with the maximum rate of monomer formation dP/dt(max) = 1.12 x 10(-8) mol/s and the rate constant K-m x 2.03 x 10(-4) mol. Subject to initial conditions described by the most probable distribution and Michaelis-Menten-type depolymerization rate expressions, population density distribution dynamics of the polymeric molecules that formed the resin were explicitly described using a deterministic approach.