PROTEIN SOIL RELEASE USING PROTEASE AS MONITORED WITH A QUARTZ-CRYSTAL MICROBALANCE

Detergency is a complex procedure comprising both chemical and mechani cal processes. In order to fully understand the chemical process, it i s necessary to uncover its basic steps by setting up a simplified mode ling system. In this study, we attempt to find the key to the detergen cy mechanism by revealing the adsorption of enzymes and surfactants on to proteins and the degradation and subsequent release of the proteins using a quartz crystal microbalance (QCM) measurement that can quanti fy minute weight changes in water over time. We first examine three di fferent proteins-gelatin, ovalbumin (OvA), and keratin. The frequency change of a QCM is traced for the release of solid protein by Nagarse( R) from the surface of a gold electrode. As observed in former studies of dissolved protein, the synergistic effects are confirmed for relea se by protease/nonionic surfactants, i.e., C-12(EO)(7) and C-16(EO)(7) . Adding anionic surfactants-sodium dodecylbenzene-sulfonate (DBS) or sodium dodecylsulfonate (SDS)-enhances the release rate at near the cr itical micelle concentrations. The amount of adsorption of the enzyme to gelatin increases in the presence of anionic or nonionic surfactant s.