Li, Z.Jin, B.Zhang, H.Bai, Z.Xue, W.Li, H.2009-12-022009-12-022008Guocheng Gongcheng Xuebao, 2008; 8(4):768-7731009-606Xhttp://hdl.handle.net/2440/54211A newly isolated Bacillus gibsonii, designated as S-2 (CGMCC1215), was cultivated for production of alkaline pectinases utilizing sugar beet pulp as growth substrate. Purification of three alkaline endopolygalacturonases (endoPGs) from the crude pectinases extract was carried out by ultra-filtration, ammonium sulphate fractionation and ion-exchange chromatography, and their enzyme activities characterized. The three purified alkaline endoPGs, designated as S-I, S-II, and S-III, had a molecular weight about 38 kDa as determined by SDS-PAGE. The K<inf>m</inf> value and optimal temperature for optimal enzyme activities of S-I, S-II and S-III were 1.2 mg/mL and 60°C, 0.9 mg/mL and 55°C, 1.1 mg/mL and 60°C, respectively. Their best performances were given at an optimal pH 10.5, and sodium polygalacturonate was found to be the best substrate. The isoelectric points of S-I, S-II and S-III were 5.4, 7.4, and 8.2, respectively. Surfactants of Tween-80 and Tween-20 and metal ions such as Mg²⁺ and Ca²⁺ stimulated the activity of S-I, S-II and S-III, whereas S-III was inhibited by Ca²⁺, and Mn²⁺ and Zn²⁺ ions inhibited the activity of the three enzymes.enalkaline endopolygalacturonasesBacillus gibsoniipurificationenzyme activityJournal article00200838722-s2.0-5224908563241107