摘要
A 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 about38kDa as determined by SDS-PAGE.The Km value and optimal temperature for optimal enzyme activities of S-I,S-II and S-III were1.2mg/mL and60℃,0.9mg/mL and55℃,1.1mg/mL and60℃,respectively.Their best performances were given at an optimal pH10.5,and sodium polygalacturonate was found to be the best substrate.The isoelectric points of S-I,S-II and S-III were5.4,7.4,and8.2,respectively.Surfactants of Tween-80and Tween-20and 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.
A 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 Km value and optimal temperature for optimal enzyme activities of S-Ⅰ, S-Ⅱ and S-Ⅲ were 1.2 mg/mL and 60 ℃, 0.9 mg/mL and 55 ℃, 1.1 mg/mL and 60 ℃, 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 Mg^2＋ and Ca^2＋ stimulated the activity of S-Ⅰ, S-Ⅱ and S-Ⅲ, whereas S-Ⅲ was inhibited by Ca^2＋, and Mn^2＋ and Zn^2＋ ions inhibited the activity of the three enzymes.
出处
《过程工程学报》
EI
CAS
CSCD
北大核心
2008年第4期768-773,共6页
The Chinese Journal of Process Engineering
基金
Beijing Municipal Commission of Education(No.20061D0502200295)
National Natural Science Foundation of China(No.30600082)
Australian Research Council International Linkage Fellowship(No.LX0560210)
关键词
净化方法
细菌
隔离方法
果胶酶
alkaline endopolygalacturonases
Bacillus gibsonii
purification
enzyme activity
