Bactericidal and antifungal activities of a low molecular weight chitosan and its N-/2(3)-(dodec-2-enyl)succinoyl/-derivatives

Low molecular weight chitosan (4.6 kDa) and N-/2(3)-(dodec-2-enyl)succinoyl/-derivatives of different degrees of substitution were tested for their antimicrobial activity against Escherichia coli, Pseudomonas aureofaciens, Enterobacter agglomerans, Bacillus subtilis, Candida kruisei and Fusarium oxysporum f. sp. radicis lycopersici. The results indicated that the chitosans show high activities against all bacteria, yeast and filamentous fungus. In fact, they suppressed fungal colony growth and inhibited fungal spore germination at 0.01% (w/v) concentration. A higher activity of chitosan and its derivatives was obtained with a substitution degree of 3 mol% for E. coli and B. subtilis, while a substitution degree of 9 mol% was usually preferable for increased activity against P. aureofaciens, E. agglomerans and C. kruesei.