Antimicrobial properties of chitosan extracted from shrimp processing waste were determined against one gram-positive bacterium methicillin-resistant Staphylococcus aureus in vitro. The antimicrobial activities of chitosan were explored by calculation of the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) in media supplemented with 200, 400, 600, 800and 1000 ppm chitosan solution. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the prepared chitosan was 800 and 1000 ppm for both bacterial strains. These results indicate that chitosan from shrimp processing waste could be used as an effective antibacterial agent in the food industry. The ability of chitosan as an adsorbent for Mn (II) ions in aqueous solution was studied. Our results show that the adsorption process is concentration-driven with high capacity of chitosan for the adsorption of these metal ions. At initial manganese concentrations of 3, 6 and 9 mg/L, the adsorbed manganese ion concentrations are 2.4122, 4. 9544, and 7.7667mg/L, respectively. chitosan produced was also characterized with Fourier Transform Infrared Spectroscopy (FTIR).