ABSTRACT
Chitosan is a natural antimicrobial which is derived from non-toxic animal resources. This study investigated and compared the antimicrobial characteristics of chitosan which was extracted from shell of Artemia cyst in the lake of Urmia with the same commercial chitosan feature to that of crab shell from A.P.T firm in Vietnam. The experiment was carried by means of two fulded method to find the minimum inhibitory concentration [MIC] of commercial chitosan and Artemia chitosans and [4,2,1,0/5,0/25,0/125,0/062 mg/ml] [6/4,3/2,1/6,0/8,0/4,0/2,0/1 mg/ml] on Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Listeria monocytogenes. MIC of Artemia chitosan for those bacteria and MIC of commercial chitosan were determined 500 ppm and 800 ppm. In the next phase, each of those four bacterias was separately exposed to MIC Artemia chitosan and during 8 h of incubation at 37°C were artificially cultivated every 2 h and colonies appearing on the plates after 24 h of incubation were counted and the death time graph of the bacterias was drown to study their destruction process in the presence of MIC of Artemia chitosan. Experimental achievements showed that in this period of destruction speed in Staphylococcus aureus was more than others and the destruction speed of Salmonella typhimurium was the least. Also studying the achieved pictures by electronic microscope from the from two bacterias, gram-positive Staphylococcus aureus and gramnegative Escherichia coli which were exposed to MIC of Artemia chitosan [500 ppm] depicted that the speed of influence by Artemia chitosanon gram-positive bacteria is much more than gram-negative bacteria. Results of this study depict great abilities of Artemia chitosan in destroying studied bacteria in comparis on with those of commercial one