Production of lactulose by β-galactosidase from kluyveromyces lactis: the effect of the substrate concentration and the temperature

Abstract

The objective of this work is to evaluate the conditions of enzymatic production of lactulose, a disaccharide with wide application in the food and pharmaceutical industries. For this, it was investigated the influence of the lactose and fructose ratio and the total concentration these carbohydrates on the synthesis of lactulose by the enzyme β-galactosidase from Kluyveromyces lactis. The optimal temperature for this conversion was also evaluated. The results showed that the lactose and fructose ratio of 15% (w/v) and 30% (w/v), respectively, provided higher lactulose synthesis. Moreover, a total carbohydrates concentration of 200 g/L, in the proportion above mentioned, was required to achieve the highest production of lactulose (10.34 g/L). Regarding the temperatures evaluated, it was found that the temperature of 50 °C favored the synthesis of lactulose, reaching a concentration of 14.95 g/L, concluding that the use of this enzyme is promising in the process of lactulose production.