Abstract: Soybean phytoesterase (SPE) was used to immobilize on nitrocellulose membrane (NCM) in this study. Through the parameters optimization of enzyme dosage, glutaraldehyde (GA) concentration, bovine serum albumin (BSA) concentration, pH value and temperature, the method of NCM immobilizing SPE was established: adding 20μl enzyme, 2μl 0.05% GA and 15 μl 0.5% BSA into test tube, then supperadding 0.03 mol/L pH 7.0 PBS buffer to 100μl, immobilizing for 8 h at 4 ℃. Comparing the characteristics between immobilized enzyme and free enzyme, the results showed that the optimum reaction temperature of immobilized enzyme is 35 ℃, 5 ℃ higher than that of free enzyme. The optimum pH value is 8.0, 0.5 higher than that of free enzyme; The sensitivity of immobilized enzyme to four pesticides (dichlorvos, methomyl, omethoate and monocrotophos) is better than that of free enzyme. So, it can be conclude that the immobilized enzyme is more suitable for rapid detection of pesticide.

Key words: soybean phytoesterase, immobilization, detection of pesticides residue