Innovative continuous biocatalytic system based on immobilized tannase: possible prospects for the haze-active phenols hydrolysis in brewing industry

Abstract

The development of biotechnological approaches for preventing chill haze formation has attracted great interest in brewing research. The current work provides an innovative biocatalytic system, based on immobilized tannase (as phenolic-degrading enzyme), for the continuous treatment of wort in fluidized-bed reactor (FBR). The covalent immobilization on chitosan beads has been performed using a food-grade cross-linker. The initial protein concentration of 1.35 mgBSAeq/mL allowed us to maximize the specific activity of the biocatalyst (0.017 I.U./mgBSAeq), which was characterized by a higher pH and storage stability than that of the free enzyme. The continuous treatment in FBR has been optimized varying the flow rate (Q v) and the amount of biocatalyst, and the suitable conditions for the continuous treatment of synthetic wort were 560 mL/min (Q v) and 5.0 g of biocatalyst. Immobilized tannase exhibited excellent operational stability in FBR and has been reused eight times retaining 60% of its initial activity. The continuous and specific haze-preventing biotechnological treatment provided in this study, and based on food-grade immobilized tannase, may be successfully applied during the phase of post-mashing, when the operating conditions (T = 40 °C, pH = 5) match those optimal for the catalytic activity of the enzyme.