Abstract
We purified a novel, thermoactive pectate lyase (Pel), designated Pel 1 from the hyperpectinolytic mutant (CT1) of Penicillium occitanis using single-step, anion-exchange chromatography. The purified Pel 1 had a pl of 6.5 and a molecular mass of approximately 39 kDa as estimated by SDS-PAGE. The activity of Pel 1 was assayed in the presence of several divalent cations at different concentrations. Although we noted that the tested divalent cations are required for maximum activity, we found that none of them could substitute for the effects of 2 mM Ca2+. Using three different carbon sources, our results showed that the highest level of Pel 1 activity (434 U/ml) was obtained in a medium supplemented with apple pectin. With polygalacturonic acid, Pel1 exhibited a Km of 0.0199 mg/ml and a V-max of 17.19 mu mol/min/mg at pH 7.0. However, at pH 9.0. the K-m and V-max values were 0.0136 mg/ml and 19.23 mu mol/min/mg, respectively. The optimum temperature and pH value required for maximal enzymatic activity were found to be 60 degrees degrees C and pH 9.0. respectively. At this pH, the half-life time stability at 60 degrees C was measured to be 16.4 min. The novel Pel1 is very thermally stable and presents alkalophilic parameters; such features are rarely exhibited by fungal Pels. (c) 2011 Elsevier Ltd. All rights reserved.