RESUMO
In this study, chitin oligosaccharides have been successfully produced using chitinases from submerged fermentation of Lecanicillium lecanii. The highest Hex, Chit and Prot production was 0.14, 0.26 and 2.05 U/mg of protein, respectively, which were attained varying pH from 5 to 8 after 96 h. Culture conditions conducted at constant pH of 6 resulted in significantly lower enzyme production. The crude enzyme was partially purified by salting out with (NH4)2SO4 followed by size exclusion chromatography to isolate the chitinase mixture for further chitin hydrolysis assays. In this regard, chitin substrates were pretreated with sonication and steam explosion prior to enzymatic reaction. Structural changes were observed with steam explosion with 11.28% reduction of the crystallinity index attained with the lowest chitin/water ratio (0.1g/mL). Pretreated chitins reached the highest production of reducing sugars (0.37 mg/mL) and GlcNAc (0.59 mg/mL) in 23.6% yield.
Assuntos
Quitina/biossíntese , Quitinases/química , Quitosana/química , Hypocreales/enzimologia , Oligossacarídeos/biossíntese , Carboidratos/química , Cristalização , Enzimas/química , Fermentação , Concentração de Íons de Hidrogênio , Hidrólise , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Vapor , Temperatura , Fatores de Tempo , UltrassomRESUMO
Hyperbranched poly-L-lactides have been synthesized by eROP in [C4MIM][PF6] media. The bis(hydroxymethyl)butyric acid molecule was used as the AB2 core co-monomer and immobilized lipase B from Candida antarctica as biocatalyst. The degree of branching could be controlled by the reaction conditions, with the maximum achieved being 0.21. The successful achievement of the hyperbranched structure is attributed to the high solvent power of substrates and products in the ionic liquid besides sustained lipase activity.