Antibacterial Action of Chitosan Produced from Shrimp Waste Against the Growth of Escherichia coli, Staphylococcus epidermidis, Proteus mirabilis and Pseudomonas aeruginosa.

The main goal of this study was to investigate in vitro the antibacterial action of chitosan (CS), in various physical forms (film, bead, powder and solution), against selected bacteria including Escherichia coli, Staphylococcus epidermidis, Proteus mirabilis and Pseudomonas aeruginosa. For this purpose, chitosan was produced by N-deacetylation of chitin under different alkaline conditions. Degree of deacetylation (DDA), molecular weight and viscosity of each form of chitosan were determined. The functional groups of chitosan were confirmed by Fourier Transform Infrared Spectroscopy and the degradation temperatures by Differential Scanning Calorimetry (DSC). Chitosan with high DDA (95%), molecular weight (149.01 KDa) and viscosity (0.2498 dL/g) was obtained by deacetylation with 50% of sodium hydroxide at 90 °C for 4 h. The antibacterial test results demonstrated the presence of significant antibacterial action of soluble chitosan against the tested pathogenic bacteria. In addition, the bacterial growth showed a considerable decrease in bacterial biomass after addition of CS, the resistance of the studied bacterial strains against soluble CS decreased in the following order: E. coli > P. mirabilis > S. epidermidis and their action process was bacteriostatic rather than bactericidal. [ABSTRACT FROM AUTHOR]