Enhancement of Antimicrobial Activity of Chitosan by Irradiation

✍ Scribed by Matsuhashi, S; Kume, T

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 240 KB
• Volume: 73
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/(sici)1097-0010(199702)73:2<237::aid-jsfa711>3.0.co;2-4

✦ Synopsis

Antimicrobial activity of irradiated chitosan was studied against Escherichia coli B/r. Irradiation of chitosan at 100 kGy under dry conditions was e †ective in increasing the activity, and inhibited the growth of E coli completely. The molecular weight of chitosan signiÐcantly decreased with the increase in irradiation dose, whereas the relative surface charge of chitosan was decreased only 3% by 100 kGy irradiation. Antimicrobial activity assay of chitosan fractionated according to molecular weight showed that 1 ] 105È3 ] 105 fraction was most e †ective in suppressing the growth of E coli. This fraction comprised only 8% of the 100 kGy irradiated chitosan. On the other hand, chitosan whose molecular weight was less than 1 ] 105 had no activity. The results show that low dose irradiation, speciÐcally 100 kGy, of chitosan gives enough degradation to increase its antimicrobial activity as a result of a change in molecular weight.