High stability of immobilized β-d-galactosidase for lactose hydrolysis and galactooligosaccharides synthesis

Abstract

β-D-Galactosidase from Kluyveromyces lactis was immobilized on glutaraldehyde-activated chitosan and used in a packed-bed reactor for the continuous hydrolysis of lactose and the synthesis of galactooligosaccharides (GOS). The biocatalyst was tested for its optima pH and temperature, thermal stability in the presence of substrate and products, and operational stability. Immobilization increased the range of operational pH and temperature, and the enzyme thermal stability was sharply increased in the presence of lactose. Almost complete lactose hydrolysis was achieved for both milk whey and lactose solution at 37 °C at flow rates up to 2.6 mL min(-1). Maximal GOS concentration of 26 g L(-1) was obtained at a flow rate of 3.1 mL min(-1), with a productivity of 186 g L(-1) h(-1). Steady-state operation for 15 days showed the reactor stability concerning lactose hydrolysis.

Recyclable solid-phase biocatalyst with improved stability by sol–gel entrapment of β-d-galactosidase

“…Kluyveromyces lactis [12] and Kluyveromyces fragilis [13], having the advantage of non-toxicity 13 and biocompatibility. Multi-walled carbon nanotubes were also functionalized with 14 glutaraldehyde in order to increase the bound enzyme amount [14].…”

Emerging Enzyme-Based Technologies for Wastewater Treatment

“…Particularly, Verma et al, showed that the thermal stability of lipase was greatly improved upon its immobilization onto carbon nanotubes (89), while Klein and coworkers showed a similar phenomenon for β-D-Galactosidase immobilized onto chitosan (90). Further, affinity immobilization was shown to exploit the specificity of the enzyme to the substrate, in different physiological conditions, to increase enzyme immobilization capacity and reusability (91).…”

Functionalized agarose as an effective and novel matrix for immobilizing Cicer arietinum β-galactosidase and its application in lactose hydrolysis

“…It was noted that soluble β-galactosidase showed 41 % activity at 70 °C, whereas the immobilized β-galactosidase retained 67 % activity at the same temperature. Immobilization also resulted in improved stability of immobilized β-galactosidase for glutaraldehyde-activated chitosan (Klein et al, 2013). The probable reason for this may be that covalent binding and crosslinking provided a more rigid external backbone for β-galactosidase immobilization.…”