LACTOPEROXIDASE (EC.1.11.1.7), an enzyme of peroxidase family, is one of the most abundant bovine milk enzymes in which enter the whey in the process of cheese production. The LACTOPEROXIDASE enzyme has been of great interest due to its valuable properties, which can be widely used in medical field as well as in food fields. Recently, some studies have revealed that thermostability of the enzyme is not appropriate to use the enzyme in industry. The purpose of the present study was to immobilization of LACTOPEROXIDASE onto copper nanoparticles, and compare the thermostability of the native and the immobilized enzyme. LACTOPEROXIDASE was purified from whey, a by-product in cheese industry by cation exchange and gel filtration chromatography .Then, purified enzyme was immobilized on the surface of copper nanoparticles by the method of Link et al. The immobilized enzyme displayed a similar pH- dependence behavior and an enhanced thermostability up to 56% compared to the native enzyme. Copper nanoparticles can be considered as an appropriate support for improvement of thermostability of the peroxidase enzymes family.

The aim of this work was to evaluate the possibilities of immobilization of LACTOPEROXIDASE (LPO) on concanavalin A-Sepharose 48 support. Significant biospecific interaction of this heme-containing glycoenzyme with Con A was established by using a-D-mannopyranoside and a-D-glucopyranoside, which are involved in the linking of the carbohydrate moieties of the enzyme with lectin. The preparation obtained indicated improved kinetic parameters (Km and Vmax) compared with the soluble form. No significant differences were observed between the optimal pH and temperature of the anchored and free enzymes. The thermal stability of the biospecifically immobilized preparation was substantially higher than that of the unbound enzyme. In addition, seven cycles of enzymatic conversion and washing of the column showed -the remarkable operational stability of immobilized LPO.

The LACTOPEROXIDASE System holds significant prominence as a pivotal protein within milk, assuming a defensive role in combating diverse strains of microorganisms, particularly those with deleterious implications for milk quality. The stabilization process of the LACTOPEROXIDASE enzyme offers numerous advantages and benefits within an academic context and allows for controlled modulation of the enzyme's effects. Stabilized enzymes have attracted considerable research attention due to their favorable attributes, including easy separation from reaction mixtures, and the potential for reusing enzymes from multiple sources, to find and improve valuable methodologies. This review summarized the role of stabilizers in enhancing the efficacy and stability of the LACTOPEROXIDASE system and antibacterial applications in cosmetics, pharmaceutical, food, and health industries. This enzyme possesses characteristics that make it an effective natural antibacterial agent, leading to the extension of the lifespan and improvement of the stability of diverse types of dairy products and milk. It is used especially in remote areas where farmers are not close to the market. The common findings confirmed the ability of stabilizers to enhance enzyme stability in unfavorable environmental conditions that result in the extension of the activity period of the enzyme. Therefore, this characteristic indirectly enhances the enzyme's remarkable effectiveness against bacteria. Finally, according to various studies, the main function of stabilizing agents is the enhancement of enzyme stability as well as the longevity of the enzyme. Overall, it seems the stabilizers have a supplementary function in improving the enzyme's ability to kill bacteria through increased enzymatic activity.

The purpose of the present study was to compare the stabilizing effect of four disaccharides alone or in combination on the LACTOPEROXIDASE (LP) derived from bovine milk during lyophilization. Sucrose, lactose, maltose, and trehalose at different concentrations (5-500 mM) were used to compare their protective effects on LP activity . The activity of lyophilized and native LP enzyme was evaluated using the procedure of Schindler with slight modifications. The antibacterial activity of the lyophilized enzyme against Pseudomonas aeroginosa, Escherichia coli, and Staphylococcus aureus was also investigated using the antimicrobial effectiveness test. Trehalose at concentration of 500 mM was the most effective cryoprotectant in protecting the enzyme activity. It preserved LP activity for 40 days, while the native enzyme lost its activity after 6 days. Combinations of disaccharides resulted in an increment in the stability of the enzyme, compared to the native enzyme. Combination of 200 mM trehalose and 200 mM sucrose were found most effective cryoprotectant in freeze-drying of LP. The lyophilized LP decreased the growth rate of Ps.aeroginosa, E.coli, and S.aureus between up to 30.8% in 106 cfu/ml and 53.3% in 105 cfu/ml . Antimicrobial efficacy of LP was more pronounced when 105 cfu/ml was used as compared to 106 cfu/ml.