title: Comparison of the performances of four hydrophilic polymers as supports for lipase immobilisation.
abstract: Four hydrophilic polymers in the form of beads - chitosan, alginate, alginate/polyvinyl alcohol (PVA), and chitosan-coated alginate - were used as supports for lipase immobilisation. Hydrogel beads were characterised by bead-size-distribution estimation, surface morphology studies, and polymer interactions assessment. Matrix performances - loading efficiency, immobilisation yield, enzyme activity, and stability retention - were evaluated and compared. Although the loading efficiency of the chitosan-coated Ca-alginate beads (79.8%) was inferior to that of the Ca-alginate (87%) and of the Ca-alginate/PVA beads (81.3%), their enzyme immobilisation yield (63.96%) was the most important. Moreover, lipase encapsulated in chitosan-coated Ca-alginate beads demonstrated better pH, thermal, and storage (89% residual activity after 30 days) stabilities. Immobilised lipase activity also increased in the order: alginate/PVA > chitosan > alginate > alginate/chitosan, and displayed a maximum at pH 8 and at temperatures of 45 °C (chitosan and Ca-alginate/PVA beads) and 50 °C (Ca-alginate and chitosan-coated Ca-alginate beads). Thus, chitosan-coated Ca-alginate beads could be considered as a suitable support for lipase immobilisation.
authors.affiliation: Institute of Engineering, Autonomous University of Baja California , Mexicali , Mexico ; Technological Institute of Mexicali , Mexicali , Mexico.
authors.forename: Lydia
authors.initials: L
authors.lastname: Toscano
authors.affiliation: Institute of Engineering, Autonomous University of Baja California , Mexicali , Mexico.
authors.forename: Gisela
authors.initials: G
authors.lastname: Montero
authors.affiliation: Institute of Engineering, Autonomous University of Baja California , Mexicali , Mexico.
authors.forename: Margarita
authors.initials: M
authors.lastname: Stoytcheva
authors.affiliation: Institute of Agricultural Science, Autonomous University of Baja California , Mexicali , Mexico.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Cervantes
authors.affiliation: Department of Biochemistry and Microbiology, Plovdiv University , Plovdiv , Bulgaria.
authors.forename: Velizar
authors.initials: V
authors.lastname: Gochev
keywords: adsorption; alginate; alginate/PVA copolymer; alginate–chitosan assembly; chitosan; encapsulation; lipase