OBTAINING MICROPARTICLES OF CALCIUM CARBONATE LOADED WITH MICROBIAL LIPASE

Abstract

At present, lipases of animal and microbial origin are increasingly used in human practice, namely in cheese production, milk chocolate production, confectionery industry, dry egg powder, production of flour, leather industry (for degreasing wool, bristles, leather), silk production, washing agents, as well as biodiesel. However, the practical use of lipase is limited by its low stability, reduced storage activity, and inability to reuse. One way to overcome these disadvantages is to microencapsulate the enzyme into various carriers. One promising carrier is calcium carbonate, characterized by ease of production and low cost. Therefore, the purpose of this work was to select the conditions for including lipase in the calcium carbonate microparticles. As the subject of the investigation, lipase of bacteria p. Pseudomonas fluorescens with activity of 27 u/mg was used in the work. This paper compares two methods of including protein molecules in carbonate microparticles: adsorption in pores (previously prepared carrier microparticles are added to the protein solution) and microencapsulation (formation of microparticles occurs simultaneously with inclusion of protein molecules). For both ways the capacity of microparticles of a carbonate of calcium by a bacterial lipase was determined and it was established that the maximum capacity equal was 0.2 mg/mg was reached when using a method of adsorption in pores. The specific activity of lipase in this case is 5.21 units/mg. The dynamics of bacterial lipase release from carbonate microparticles has been investigated. It has been found that within 90 minutes the degree of lipase release from microparticles does not exceed 28%, and the decrease in its specific activity does not exceed 10%. This fact suggests a higher prolongation of the action of lipase included in calcium carbonate microparticles compared to native. The operational stability of the bacterial lipase included in the calcium carbonate microparticles was evaluated as compared to native lipase. It was found that the temperature optimum did not occur, it remained at 37 ° C, but the operating stability increased in the lower temperature area. The optimum pH shifted from the slightly alkaline (pH 8.0) towards the neutral (pH 7.0), wherein in the region of alkaline pH values the operational stability of the microencapsulated lipase significantly increases. Microencapsulation of bacterial lipase into carbonate microparticles has been shown to increase storage stability by a factor of twice that of native.