The β-galactosidase immobilization protocol determines its performance as catalysts in the kinetically controlled synthesis of lactulose

• Main Authors: de Albuquerque, T.L (Author), de Oliveira Costa, T. (Author), Fernandez-Lafuente, R. (Author), Gonçalves, L.R.B (Author), Neto, C.A.C.G (Author), Rocha, M.V.P (Author), Silva, N.C.G.E (Author)
• Format: Article
• Language: English
• Published: Elsevier B.V. 2021
• Subjects: agarose; Article; beta galactosidase; beta-Galactosidase; biocatalysis; Biocatalysis; biocatalyst; carbohydrate synthesis; catalyst; chemical composition; chemistry; chitosan; conformational transition; controlled study; enzyme activity; enzyme immobilization; enzyme inactivation; Enzyme modulation; Enzymes, Immobilized; enzymology; fructose; fungal protein; Fungal Proteins; glutaraldehyde; glycidol; glycine; immobilized enzyme; incubation temperature; Kinetically controlled synthesis (KCS); kinetics; Kinetics; Kluyveromyces; Kluyveromyces lactis; lactulose; Lactulose; nonhuman; polyethyleneimine; structure analysis; synthesis; temperature sensitivity; whey protein
• Online Access: View Fulltext in Publisher

 In this paper, 3 different biocatalysts of β-galactosidase from Kluyveromyces lactis have been prepared by immobilization in chitosan activated with glutaraldehyde (Chi_Glu_Gal), glyoxyl agarose (Aga_Gly_Gal) and agarose coated with polyethylenimine (Aga_PEI_Gal). These biocatalysts have been used to catalyze the synthesis of lactulose from lactose and fructose. Aga-PEI-Gal only produces lactulose at 50 °C, and not at 25 or 37 °C, Aga_Gly_Gal was unable to produce lactulose at any of the assayed temperatures while Chi_Glu_Gal produced lactulose at all assayed temperatures, although a lower yield was obtained at 25 or 37 °C. The pre-incubation of this biocatalyst at 50 °C permitted to obtain similar yields at 25 or 37 °C than at 50 °C. The use of milk whey instead of pure lactose and fructose produced an improvement in the yields using Aga_PEI_Gal and a decrease using Chi_Glu_Gal. The operational stability also depends on the reaction medium and of biocatalyst. This study reveals how enzyme immobilization may greatly alter the performance of β-galactosidase in a kinetically controlled manner, and how medium composition influences this performance due to the kinetic properties of β-galactosidase. © 2021 Elsevier B.V.