Purification and characterization of thermostable pectate lyase with protopectinase activity from thermophilic Bacillus sp TS 47

A strain of thermophilic bacterium, Bacillus sp., with pectolytic activity has been isolated. It produced an extracellular endo-polygalacturonate trans-eliminase (PL, EC 4.2.2.1) when grown at 60 degreesC on a medium containing polygalacturonate (PGA). The PL was purified by hydrophobic, cation exchange, and size exclusion column chromatographies. The molecular mass of the enzyme was 50 kDa by SDS-PAGE. The isoelectric point of the enzyme was pH 5.3. The enzyme had a half-life of 13 and Ih at 65 and 70 degreesC, respectively, and showed optimal activity around at 70 degreesC and pH 8.0. It had protopectinase activity, besides PL activity, on lemon protopectin and cotton fibers. The first 20 amino acids sequence of the enzyme had significant similarity with that of PL from methophilic Bacillus subtilis, with 50% identity.