Síntese biocatalítica, recuperação e caracterização físico-química do ácido maltobiônico

Abstract

Maltobionic acid consists in a polyhydroxy acid derived from maltose. Due to its humectant power and antioxidant activity, has been used to a greater extent in formulations of products with cosmetological and dermatological purposes. Maltobionic acid is obtained in association with sorbitol by the action of glucose-fructose oxidoreductase (GFOR) and glucono-δ-lactonase (GL) enzymatic complex present in Zymomonas mobilis bacteria cells. In this work the production of maltobionic acid and respective salts – maltobionate - from maltose and maltose syrup, was evaluated in relation to substrate concentration and with respect to pH and temperature of the enzymatic reaction. In view of the potential applications, the purification and physicochemical characterization of these compounds were carried out. In maltobionic acid production using 700 mmol/L of maltose syrup, higher values of productivity and maximum specific production rate were reached at 39 °C and pH 6.4 (5.62 mmol/h and 2.17 mmol/h/g, respectively). Using 1000 mmol/L of purified maltose, productivity and maximum specific production rate were superior (8.25 mmol/h and 5.24 mmol/h/g) when compared to utilization of 700 and 1500 mmol/L of maltose (5.67 mmol/h, 4.06 mmol/h/g and 3.77 mmol/h, 1.73 mmol/h/g, respectively). Regarding purification, using methanol or ethanol 80% (v/v) at 22 ± 2 °C, high purity of the maltobionate salts (~98%) was achieved. Considering the characterization of maltobionic acid and its salts, information of molecular structure, thermal analyzes, solubility, acid dissociation constant, melting point and specific rotational power were obtained. In general, this work demonstrated the high yield of products - maltobionic acid and salts – obtained in enzymatic reaction catalyzed by GFOR/GL and relevant data of products purification and characterization. These results are important considering the potentiality of application of these compounds and the reduced information addressed in the specialized literature.