Monday, May 4, 2009
9-56
CHITOOLIGOMERS PRODUCTION BY Metarhizium anisopliae
Cristiane Fernandes Assis Sr., Nathália Kelly Araújo, Gorete Ribeiro Macedo, and Everaldo Silvino Santos. Departamento de Engenharia Química, Universidade Federal do Rio Grande do Norte, Núcleo de Tecnologia, Lagoa Nova, s/n, Campus Universitário, Natal, Brazil
Chitinolytic enzymes are produced by microbes, bacteria, fungus and some plants. The products of hydrolysis of chitosan are chitoligosaccharides and these compounds are useful for application in various fields because they have specific biological activities. The aim of this work was to assay the kind of chitooligomers (dimers until hexamers) produced by Metarhizium anisopliae and its respective concentration in different times of hydrolysis. Metarhizium anisopliae was cultured in liquid medium (containing 0.2%, and chitosan, 0.1% KH2PO4, 0.05% MgSO4, 1.4; 0.05% KCl, 0.5; 0.3% yeast extract, 0.5%; bacto-peptone, 0.2% NaNO3, 0.001% FeSO4) using shaken flasks at 25ºC and 110 rpm. The chitosanolytic enzyme activity was assayed by measuring the increase in the reducing sugar released from chitosan. The reaction mixture contained 0.5 mL of enzyme solution and 1% chitosan in a final volume of 1.0 mL. After incubation at 55ºC for differents times the amount of reducing sugar released was measured by a Dinitrosalicylic acid Method (DNS). The concentrations of chitooligomers, from dimmers to hexamers were determined by high-performace liquid chromatography (HPLC). It was observed that Metarhizium anisopliae was able to produce chitoogomers from dimmers to hexamers The highest amounts of oligomers (GlcNAc)n n =2 – 5 were found in 20 minutes. It was observed that hexamers, a chitooligomer with a great pharmaceutics interest, was found in 30 minutes of hydrolysis with a concentration of 0.13 mg/mL.