title: Production of cyclodextrins in a fluidized-bed reactor using cyclodextrin-glycosyl-transferase.
abstract: Cyclodextrin-glycosyl-transferase (EC2.4.1.19), produced by Wacker (Munich, Germany), was purified by biospecific affinity chromatography with beta-cyclodextrin (beta-CD) as ligand, and immobilized into controlled pore silica particles (0.42 mm). This immobilized enzyme (IE) had 4.7 mg of protein/g of support and a specific activity of 8.6 mumol of beta-CD/(min.gIE) at 50 degrees C, pH 8.0. It was used in a fluidized-bed reactor (FBR) at the same conditions for producing cyclodextrins (CDs) with 10% (w/v) maltodextrin solution as substrate. Bed expansion was modeled by the Richardson and Zaki equation, giving a good fit in two distinct ranges of bed porosities. The minimum fluidization velocity was 0.045 cm/s, the bed expansion coefficient was 3.98, and the particle terminal velocity was 2.4 cm/s. The FBR achieved high productivity, reaching in only 4 min of residence time the same amount of CDs normally achieved in a batch reactor with free enzyme after 24 h of reaction, namely, 10.4 mM beta-CD and 2.3 mM gamma-CD.
authors.affiliation: Chemical Engineering Department, State University of Maringá, PR-Brazil.
authors.forename: P W
authors.initials: PW
authors.lastname: Tardioli
authors.forename: G M
authors.initials: GM
authors.lastname: Zanin
authors.forename: F F
authors.initials: FF
authors.lastname: de Moraes
mesh_terms: D019149:Bioreactors; D001709:Biotechnology / Q000295:instrumentation / Q000379:methods; D002846:Chromatography, Affinity; D003505:Cyclodextrins / Q000096:biosynthesis / Q000138:chemical synthesis*; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005964:Glucosyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D012685:Sepharose
chemical_list: D003505:Cyclodextrins; D004800:Enzymes, Immobilized; D012685:Sepharose; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase