Increased activity and stability of Candida rugosa lipase in reverse micelles formed by chemically modified AOT in isooctane

Sodium his (2-ethylhexyl polyoxyethylene) sulfosuccinates, which can be structurally viewed as chemically modified AOT (MAOT), were prepared and successfully used to form reverse micelles in isooctane. The activity and stability of Candida rugosa lipase (glycerol-ester hydrolase, EC 3.1.1.3) appreciably increased in the MAOT/isooctane reverse micellar system compared with the AOT/isooctane system taking the hydrolysis of olive oil as a model reaction. The best polymerization number of oxyethylene group was found to be 2.0, which corresponded to a maximum enzyme activity of twice that in the AOT/isooctane system. The half-life of lipase in the MAOT micellar system was twice that in the AOT micellar system. The optimal operational conditions remained unchanged. The Michaelis kinetics showed that the maximum reaction rate obviously increased in the MAOT micellar system compared with that in the AOT micellar system, while the change in the Michaelis constant was insignificant. (C) 2001 Society of Chemical Industry.