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The use of β-galactosidase in food products has been a major focus of the industry. Therefore, the development of efficient and inexpensive methodologies to purify it is essential. Thus, this study aimed to recover the enzyme β-galactosidase (β-gal) by ion-exchange chromatography in a fixed-bed column. Batch adsorption tests were performed using four types of adsorbents. The β-gal adsorption capacity in batch mode using Streamline DEAE resin presented the best performance, with a retention capacity of 18.77 ± 0.14 U/g at pH 6.0. A 22 experimental design was applied to optimize the β-gal recovery using an AKTA Start system, evaluating the ionic strength and the pH as process parameters. The results showed that ionic strength exerted a greater influence on fold purification (FP). The β-gal fraction in elution using 0.1-0.4 M of NaCl showed a yield of 51.65 ± 0.17% and FP of 2.00 ± 0.43. Electrophoresis confirmed the β-gal recovery, where an evident band with a molecular weight between 60 and 120 kDa was observed. These results point to the recovery of a stable β-gal of K. lactis with potential industrial applications.

The present study aimed to evaluate the lactose hydrolysis conditions from "coalho" cheese whey using β-galactosidase (β-gal) produced by Kluyveromyces lactis immobilized with sodium alginate. Three sodium alginate-based immobilization systems were evaluated (0.5, 0.7, and 1% w/v) for maximizing the immobilization yield (Y), efficiency (EM), and recovered activity (ar). The lactose hydrolysis capacity of the immobilized form of β-gal was determined, and simulated environments were used to assess the preservation of the immobilized enzyme in the gastrointestinal tract. The results showed that β-gal immobilization with 1% (w/v) sodium alginate presented the best results (EM of 66%, Y of 41%, and ar of 65%). The immobilization system maintained the highest pH stability in the range between 5.0 and 7.0, with the highest relative activity obtained under pH 5 conditions. The temperature stability was also favored by immobilization at 50 °C for 30 min was obtained a relative activity of 180.0 ± 1.37%. In 6 h, the immobilized β-gal was able to hydrolyze 46% of the initial lactose content. For the gastrointestinal simulations, around 40% of the activity was preserved after 2 h. Overall, the results described here are promising for the industrial applications of β-galactosidase from K. lactis .