Microencapsulação em spray dryer de células de Kluyveromyces marxianus que expressam atividade de β-galactosidase

Abstract

The β-galactosidase is an enzyme of significant commercial importance and has found widespread applications in the industry due to its versatility. Researchers are actively seeking suitable methods for its industrial utilization, leading to the immobilization of β-galactosidase to enhance handling, utilization, and recyclability. Various immobilization methods exist, with adsorption, encapsulation, and cross-linking being the most commonly employed. Microencapsulation, a specific encapsulation method, involves the formation of microcapsules to protect the target agent. This method has the potential to enhance morphological stability, reduce enzymatic denaturation, improve physical-chemical permeability, and enhance enzymatic biocompatibility. In light of the above, the primary objective of this study was to immobilize β-galactosidase enzymatic activity in K. marxianus cells through microencapsulation. The selected wall materials for microparticle formation were sodium alginate, maltodextrin DE10, gum arabic, and isolated soy protein, each at a concentration of 2%. Microencapsulation was achieved through spray drying, employing the following drying parameters: drying air temperature of 90 °C, atomization air flow rate of 40 L/min, drying air inlet flow of 1.65 m³/min, and a feeding solution flow rate of 0.600 L/h. Among the chosen wall materials, maltodextrin DE10 and isolated soy protein (ISP) demonstrated superior performance in preserving catalytic activity during refrigerated storage (87.5% and 91.9%) and at room temperature (83.0% and 75.0%), exhibiting low moisture content (4.38% and 3.49%) and water activity (0.40 and 0.37). Furthermore, these materials maintained enzymatic activity (20% and 25%) post-immobilization. The uncoated cell also yielded promising results, retaining 20% of its activity after spray drying and achieving the highest drying efficiency (60.5%). This study underscores the viability of microencapsulation as an alternative to utilizing β-galactosidase in its liquid extracellular form. The immobilization of K. marxianus cells proved effective in maintaining enzymatic activity, and the possibility of using the enzyme without purification suggests potential cost savings in the production process