The stability of Candida rugosa lipase coated with glutamic acid didodecyl ester ribitol amide was investigated taking esterification of lauryl alcohol and lauric acid in isooctane as a model reaction. At 30degreesC, the half-life of the activity of the coated lipase was ca 10h, the enzyme activity became less changed after 12h and the residual activity was 39% of the initial value. The coated lipase obeyed a first-order deactivation model with a deactivation energy of 29.9 J(.)mol(-1).