Sodium bis (2 - ethylhexyl polyoxyalkylene) sulfosuccinates (SEPES) were prepared and used to form the reversed micelles in isooctane. Taking the hydrolysis of olive oil as a model reaction

the effects of average polymerization number ( n) of ethylene oxide and water content on the activity and stability of lipase in the reversed micelles were investigated. It was found that the activity

the apparent turnover number

and the deactivation rate coefficient of lipase in the reversed micelles formed by SEPES at n=2.0 in isooctane were respectively 2.2

2.1 and 0.39 times

more than those in AOT/isooctane reversed micelles

while the apparent Michaelis constants of lipase in the two systems were of little differ-