title: Hydrolysis of pullulan by entrapped pullulanase in Ca/alginate beads.
abstract: Pullulanase from Klebsiella pneumoniae was entrapped into calcium alginate beads. Its activity was estimated by the determination of number-average molar masses using two different methods: a colorimetric assay of reducing ends (REs) and a size-exclusion chromatography/multiangle light scattering/differential refractive index. The second method also provided weight-average molar masses of hydrolyzed pullulan and the quantity of maltotriose (DP3) and its multiples (DP6 and DP9) produced by the enzymatic treatment. The alginate beads showed a good retention of the loaded pullulanase (30%), and the system showed a downturn of hydrolysis kinetics in comparison with free pullulanase due to the limiting access of substrate-enzyme. On the contrary with the results obtained from free enzyme hydrolysis, for which a large distribution of pullulan fragments is observed during the treatment, the immobilized enzyme system has evidenced, during the enzymatic treatment, the coexistence of native or only slightly degraded pullulan chains together with maltotriose units. Complete hydrolysis of pullulan chains was achieved once diffused into the gel.
authors.affiliation: Normandie Université, Caen, France; Laboratoire Polymères Biopolymères Surfaces, Université de Rouen, F-76821 Mont Saint Aignan, France; CNRS UMR 6270 and FR3038, F-76821 Mont Saint Aignan, France.
authors.forename: Sarah Nawel
authors.initials: SN
authors.lastname: Gasmi
authors.forename: Christophe
authors.initials: C
authors.lastname: Rihouey
authors.forename: Luc
authors.initials: L
authors.lastname: Picton
authors.forename: Didier
authors.initials: D
authors.lastname: Le Cerf
mesh_terms: D000464:Alginates / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005936:Glucans / Q000378:metabolism*; D020723:Glucuronic Acid / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006603:Hexuronic Acids / Q000737:chemistry; D006868:Hydrolysis; D007700:Kinetics; D007709:Klebsiella / Q000201:enzymology; D008863:Microspheres; D008970:Molecular Weight; D012031:Refractometry; D014312:Trisaccharides / Q000737:chemistry
chemical_list: D000464:Alginates; D004800:Enzymes, Immobilized; D005936:Glucans; D006603:Hexuronic Acids; D014312:Trisaccharides; C008317:maltotriose; D020723:Glucuronic Acid; C009109:pullulan; D006026:Glycoside Hydrolases; C100181:pullulanase
keywords: calcium alginate beads; entrapped enzyme; hydrolysis process; kinetics; pullulan