Optimization of a dual-functional biocatalytic system for continuous hydrolysis of lactose in milk.

In this study, an amino-functionalized silica matrix encapsulating β-galactosidase was first synthesized in situ, with subsequent covalent anchoring of lysozyme to the outer part of the amino-grafted matrix. Fourier transform infrared (FTIR) spectra verified that β-galactosidase was successfully encapsulated. Meanwhile, the co-immobilized enzymes were demonstrated to retain suitable enzymatic activities and outstanding operational stability during successive reaction cycles. Furthermore, when used for lactose removal from skim milk, the packed-bed column system achieved both a high lactose hydrolysis rate and microbial inactivation ratio during 30 days of continuous operation. Notably, this system exhibited favorable stability during 60 days of continuous hydrolysis of lactose in solution and thus may be appropriate for further development for use in industrial lactose removal from milk.