Antifungal activity of chitosan oligomer prepared using chitosanase of Aeromonas media KLU 11.16

Abstract

Chitosan oligomer is a hydrolysis product of chitosan which can be prepared by enzymatic method, including chitosanase that may be produced by bacteria. Previously, chitosanase from Aeromonas media KLU 11.16 has been purified and characterized. The aim of this study was to analyze the bioactivity of chitosan oligomer prepared by using Aeromonas media KLU 11.16 chitosanase, as antifungal. Chitosan oligomer was prepared from shrimp waste chitosan, and hydrolyzed by 8U chitosanase per gram chitosan. The reaction time was for 2, 3 and 4 hours at 30°C. The oligomer produced then determined their yields and viscosities; and was identified by using a thin layer chromatography (TLC). Antifungal activity test against Aspergilus flavus, A. niger, Eurotium amstelodami and Emericella nidulans was performed on selected oligomers based on consideration of yield and TLC result, with oligomer concentrations of 0; 50; 100 and 200 ppm. The result showed that hydrolysis chitosan by Aeromonas media KLU 11.16 chitosanase for 4 hours reduced the viscosity from 187.5 to 13 cPs, and produced oligomers 96.14% of yield. The oligomers identified by TLC were monomer (1 unit) to hexamer (6 unit), and showed their antifungal activity against the four fungi tested. The best inhibition was showed by 200 ppm of oligomer against A. flavus.