Inhibition Efficiency of a Mixed Solution of Bamboo Vinegar and Chitosan against Ralstonia solanacearum

Abstract

The inhibition efficienies of mixed solutions of bamboo vinegar and chitosan against Ralstonia solanacearum, an important bacterial wilt pathogen of tomato, were evaluated by examining the time-dependent changes in optical density (OD) values for different degrees of deacetylation (DDs) and concentrations of chitosan. The results indicated that the mixed solutions had better antibacterial activity than did only raw bamboo vinegar; and a higher DD and concentration of chitosan, resulted in better inhibition efficiencies. In this study, a mixed solution with a 78% DD and 1.5% concentration of chitosan showed the best inhibitory effect on bacterial growth. The cell membrane of the bacterium was damaged by chitosan, which was confirmed by analytical electron microscopy. The inhibition of bacterial growth may have been due to the interaction between the positive charge of NH3(superscript +) of chitosan and the negative charge of the bacterial cell membrane.