The aim of this work was to develop a multifunctional reactor to carry out the enzymatic process of biodegradation of tannins. An integrated reaction system consists of a stirred tank reactor and a spiral-wound membrane module. The system was used for simultaneous reaction and product separation during the enzymatic hydrolysis of tannic acid. On the basis of kinetic investigations, a kinetic equation for the enzymatic hydrolysis of tannic acid to gallic acid by tannase was developed. It was demonstrated that the kinetics of enzymatic hydrolysis of tannic acid catalyzed by tannase can be described by a kinetic equation of the Michaelis-Menten type with the competitive product inhibition. The design of the reactor ensured the entrapment of enzyme within the reactor volume, and, in the same time, continuous separation of gallic acid. A multifunctional membrane reactor has been designed. The reactor consisted of a stirred vessel and a spiral-wound membrane module. The process was run under optimal conditions for the enzyme activity (pH 5.5, 30oC). Prolonged use of the enzyme was achieved with good efficiency. A mathematical model describing the process in the reactor has been developed. The model, based on kinetic studies, has been demonstrated to describe properly the behavior of the reactor. A good agreement of the experimental results with the calculated ones was obtained. The experimental results were also compared with the existing literature data concerning the mass transfer in spiral membrane modules. A dimensionless correlation of the Sh=f(Re,Sc) type was used to describe the data obtained. A good agreement of the literature results with own data was observed.