Comparative study of kinetic and interfacial properties of a novel Rhizopus oryzae lipase and ROL29

¹ Laboratoire de biochimie, ENIS, Route de Soukra, “BPW”, 3038 Sfax –Tunisia
² Unité de service commun pour la recherche scientifique, FSS, Route de Soukra, Km 3.5 ; BP 802, 3038 Sfax-Tunisia

^* riadh_fss@yahoo.fr

Abstract

We compared several kinetic and interfacial properties of a lipase from a novel strain of Rhizopus oryzae (ROL_w) with ROL29 lipase. In contrast to ROL29, ROL_w was able to hydrolyze triolein emulsion in the absence of any additive, like bovine serum albumin (BSA). Furthermore, unlike Rhizopus oryzae lipase (ROL29), kinetic study of ROL_w lipase shows linear dependency when using tributyrin emulsion as substrate. ROL_w can tolerate, more efficiently than ROL29, the accumulation of long-chain free fatty acids at the interface when olive oil emulsion was used as substrate. The critical surface pressure π_c of penetration into phosphatidyl choline from egg yolk films was found to be 23 mN/m with ROL_w, in contrast to a value of 10 mN/m obtained with ROL29. The effect of calcium ion and synthetic detergent on the two lipases was studied. In contrast to ROL29, ROL_w was activated in the presence of 100 lmoles TX-100. No significant difference on the two lipase activity was observed in presence or absence of calcium ion.