Antimicrobial effect of Chitosan and Nano-Chitosan against some Pathogens and Spoilage Microorganisms

An experiment was conducted to investigate the antimicrobial effect of chitosan and nano-chitosan. Two Gram-negative, three Gram-positive bacteria and three fungal strains were used as test microorganisms. The obtained results indicated that 88% of nano-chitosan particle size was in the range of 93.76nm and 12% in 405nm. Nano-chitosan showed maximum antibacterial activity against S. aureus and L. monocytogenes with inhibition zone of 30mm (23µg/ml concentration) and the lowest 23mm with E. coli at the same concentration. Other tested bacteria were affected in different degrees. The MIC and MLC ranged between 64 to 256 and 128 to 512µg/ml, respectively. The highest effect was against S. aureus at 23.04µg/ml. Chitosan solution was found to have less antifungal activity against C. albicans when compared to nano-chitosan. MIC and MLC for chitosan and nano-chitosan were recorded at 64 and 128µg/ml with chitosan and 23.04 and 46.08µg/ml with nano-chitosan. The highest nano-chitosan activity was recorded against S. cerevisiae, 7 and 16µg/ml for MIC and MLC, respectively. Nano-chitosan at concentrations 3.0 and 4.5µg/ml were the most effective to retard fungal activity.