A Low-Temperature-Active Alkaline Pectate Lyase from Xanthomonas campestris ACCC 10048 with High Activity over a Wide pH Range

Alkaline pectate lyases are favorable for the textile industry. Here, we report the gene cloning and expression of a low-temperature-active alkaline pectate lyase (PL D) from Xanthomonas campestris ACCC 10048. Deduced PL D consists of a putative 27-residue signal peptide and a catalytic domain of 320 residues belonging to family PF09492. Recombinant PL D (r-PL D) produced in Escherichia coli was purified to electrophoretic homogeneity with a single step of Ni2+-NTA affinity chromatography and showed an apparent molecular weight of similar to 38 kDa. The pH and temperature optima of r-PL D were found to be 9.0 A degrees C and 30 A degrees C, respectively. Compared with its microbial counterparts, r-PL D had higher activity over a wide pH range (> 45 % of the maximum activity at pH 3.0-12.0) and at lower temperatures (> 35 % of activity even at 0 A degrees C). The K (m) and V (max) values of r-PL D for polygalacturonic acid were 4.9 g l(-1) and 30.1 mu mol min(-1) mg(-1), respectively. Compared with the commercial compound pectinase from Novozymes, r-PL D showed similar efficacy in reducing the intrinsic viscosity of polygalacturonic acid (35.1 % vs. 36.5 %) and in bioscouring of jute (10.25 % vs. 10.82 %). Thus, r-PL D is a valuable additive candidate for the textile industry.