title: Purification and characterization of levansucrases from Bacillus amyloliquefaciens in intra- and extracellular forms useful for the synthesis of levan and fructooligosaccharides.
abstract: The intra- and extracellular levansucrase (LS) activities produced by Bacillus amyloliquefaciens were promoted by supplementing the sucrose medium with yeast and peptone as nitrogen sources. These activities were purified by polyethylene glycol (PEG) fractionation for the first time. PEGs of low molecular weight selectively fractionated the intracellular LS activity rather than the extracellular LS activity. Contrary to other LSs, B. amyloliquefaciens LSs exhibited high levan-forming activity over a wide range of sucrose concentrations. The optimum temperatures for the intra- (25-30 °C) and extracellular (40 °C) LS transfructosylation activities were lower than those for the hydrolytic activities (45-50 °C; 50 °C). In addition, the catalytic efficiency for the transfructosylation activity of intracellular LS was higher than that of extracellular LS. These differences between intra- and extracellular LSs reveal the occurrence of certain conformational changes to LS upon protein secretion and/or purification. This study is the first to highlight that B. amyloliquefaciens LSs synthesized a variety of FOSs from various saccharides, with lactose and maltose being the best fructosyl acceptors.
authors: Department of Food Science and Agricultural Chemistry, McGill University, Ste-Anne de Bellevue, Quebec, Canada.
authors: Feng
authors: F
authors: Tian
authors: Lotthida
authors: L
authors: Inthanavong
authors: Salwa
authors: S
authors: Karboune
mesh_terms: D001407:Bacillus / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D055162:Biocatalysis; D002241:Carbohydrates / Q000096:biosynthesis*; D005591:Chemical Fractionation / Q000379:methods*; D005110:Extracellular Space / Q000187:drug effects / Q000201:enzymology*; D005630:Fructans / Q000096:biosynthesis; D006602:Hexosyltransferases / Q000302:isolation & purification* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D042541:Intracellular Space / Q000187:drug effects / Q000201:enzymology*; D007700:Kinetics; D009844:Oligosaccharides / Q000096:biosynthesis; D011092:Polyethylene Glycols / Q000737:chemistry; D013379:Substrate Specificity; D013395:Sucrose / Q000494:pharmacology; D013696:Temperature
chemical_list: D002241:Carbohydrates; D005630:Fructans; D009844:Oligosaccharides; C116580:fructooligosaccharide; D011092:Polyethylene Glycols; D013395:Sucrose; C072599:levan; D006602:Hexosyltransferases; C021513:levansucrase