Secagem de células de Kluyveromyces marxianus por spray drying visando obtenção de um biocatalisador que expressa atividade de β-galactosidase

Abstract

Kluyveromyces marxianus is a yeast that produces intracellular β-galactosidase, obtained by submerged fermentation. This study evaluated the drying of Kluyveromyces marxianus cells by spray drying as a method for recovering β-galactosidase. Thus, initially, the effect of different drying air temperatures (90, 120, and 150 °C) without maltodextrin and with maltodextrin as a carrier agent (120 and 150 °C) was studied. Drying Kluyveromyces marxianus cells with maltodextrin at 120 °C produced the highest enzymatic activity (447.71 µmol/min). This powder had a moisture content of 3.02%, a water activity of 0.21, a solubility of 82.63%, a hygroscopicity of 16.4 g/100 g dry mass, and a yield of 62%. In this context, the study continued by evaluating the addition of sodium tripolyphosphate (TPP) as a crosslinking agent, alone and in combination with maltodextin. To evaluate storage stability and morphology by scanning electron microscopy (SEM), the following drying conditions at 120 °C were selected: i) without maltodextrin; ii) with maltodextrin; iii) with TPP; and iv) maltodextrin combined with TPP. Thermal stability (30, 35, 40, and 50°C) was evaluated in the dry cell at 120°C in a spray dryer with maltodextrin and maltodextrin and TPP. The combination of maltodextrin and TPP proved effective in preserving the cell with β-galactosidase activity by contributing to the preservation of enzymatic activity and cell stability over time, demonstrating potential for formulations with longer shelf life and industrial application.