Enzymatic hydrolysis of chitin pretreated by rapid depressurization from supercritical 1,1,1,2-tetrafluoroethane toward highly acetylated oligosaccharides

Abstract

The hydrolysis of chitin treated under supercritical conditions was successfully carried out using chitinases obtained by an optimized fermentation of the fungus Lecanicillium lecanii. The biopolymer was subjected to a pretreatment based on suspension in supercritical 1,1,1,2-tetrafluoroethane (scR134a), which possesses a critical temperature and pressure of 101°C and 40bar, respectively, followed by rapid depressurization to atmospheric pressure and further fibrillation. This methodology was compared to control untreated chitins and chitin subjected to steam explosion showing improved production of reducing sugars (0.18mg/mL), enzymatic hydrolysis and high acetylation (FA of 0.45) in products with degrees of polymerization between 2 and 5.

Keywords: Chitin; Chitinases; Lecanicillium lecanii; Supercritical 1,1,1,2-tetrafluoroethane; scR134a.