Extraction, purification and characterization of invertase from Candida guilliermondii isolated from peach solid wastes

Extração, purificação e caracterização da invertase de Candida guilliermondii isolada de resíduos sólidos de pêssego

Abstract

The best conditions for in vitro sucrose hydrolysis based on invertase from Candida guilliermondii (ICg) were studied and the kinetic parameters K_M,V_max, and thermal stability of ICg were determined. Candida guilliermondii (Cg) yeast isolated and lyophilized from peach solid wastes was identified using the API 20C AUX method. Subsequently, the Cg was submitted to an autolysis process using NaHCO3 at 200 mM under 200 rpm stirring and 40 °C for 24 h. The enzyme extracts obtained were recovered through precipitation with acetone followed by dialysis and ion-exchange chromatography. The extract purified through precipitation with acetone had activity of 27.7 U.mg^-1 and 56% recovery whereas the chromatography process yielded 46.5 U.mg^-1 and 44.8%. The optimal sucrose hydrolysis conditions were pH 5.0 and 50 °C, resulting in KM of 30.5 mM and 28.7 mM sucrose, respectively, at 25 °C and 50 °C, both with Michaelian behavior. Thermal inactivation of ICg exhibited first-order apparent kinetics and its residual activity was typically linear between 40 °C and 70 °C. Three isoenzymes were detected through electrophoresis.

Index terms
Yeast; autolysis; isoenzymes; inverted sugar