Application of cellulosic materials as supports for single-step purification and immobilization of a recombinant β-galactosidase via cellulose-binding domain

This study aimed to develop single-step purification and immobilization processes on cellulosic supports of beta-galactosidase from Kluyveromyces sp. combined with the Cellulose-Binding Domain (CBD) tag. After 15 min of immobilization, with an enzymatic load of 150 U/g(support), expressed activity values reached 106.88 (microcrystalline cellulose), 115.03 (alkaline nanocellulose), and 108.47 IU/g (acid nanocellulose). The derivatives produced were less sensitive to the presence of galactose in comparison with the soluble purified enzyme. Among the cations assessed (Na+, K+, Mg2+, and Ca2+), magnesium provided the highest increase in the enzymatic activity of beta-galactosidases immobilized on cellulosic supports. Supports and derivatives showed no cytotoxic effect on the investigated cell cultures (HepG2 and Vero). Derivatives showed high operational stability in the hydrolysis of milk lactose and retained from 53 to 64% of their hydrolysis capacity after 40 reuse cycles. This study obtained biocatalyzers with promising characteristics for application in the food industry. Biocatalyzers were obtained through a low-cost one-step sustainable bioprocess of purification and immobilization of a beta-galactosidase on cellulose via CBD.

Automated summary

This study developed a one-step purification and immobilization method for β-galactosidase on cellulosic supports. The immobilized enzyme showed high activity within 15 minutes and lower sensitivity to galactose compared to the soluble enzyme. Magnesium ion had the highest impact on the enzymatic activity of the immobilized enzyme on cellulosic supports. The derivatives had no cytotoxic effect on cell cultures and retained high hydrolysis capacity after multiple reuse cycles.