Lipid oxidation processes in bulk, micelle, O/W emulsion and micoencapuslated systems were obser ved. Oxidation of lipid in O/W emulsion and micoencapuslated systems proceeded more slowly for the smaller oil-droplets. Models for describing the characteristics in the processes were proposed based on the kinetic equation of autocatalytic type. Alkyl glycosides were synthesized through -glucosidase-catalyzed condensation in an aqueous-organic biphasic system, and esters consisting hydrophilic and hydrophobic moieties were also synthesized through lipase-catalyzed condensation in a microaqueous organic solvent system. Models which describe physicochemical phenomena occurring in the systems were proposed, and the factors affecting the product yields were quantitatively analyzed based on the models.