Carboxymethyl chitin and chitosan derivatives: Synthesis, characterization and antibacterial activity

Water-soluble carboxymethyl chitin (CMCT) 1a–b, and chitosan (CMCS) 2a–b derivatives were synthesized and evaluated for antibacterial activity. The synthesized compounds were characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Thermal properties of the synthesized compounds were studied by thermogravimetric analysis (TGA) and their surface morphologies examined by scanning electron microscopy (SEM). Antibacterial activity of the chitosan (CS) 2 and the synthesized derivatives were tested against both gram-negative (Shigella flexneri, Enterococcus faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Vibrio paraheamolyticus) and gram-positive (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus) bacterial strains. CS 2 shows antimicrobial activity against all tested pathogenic bacteria, whereas CMCS 2a shows antimicrobial activity against Shigella flexneri, Bacillus cereus, and Bacillus subtilis. CMCS 2b shows antimicrobial activity against Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus. CMCT 1a only shows antimicrobial activity against Bacillus subtilis and 1b shows antimicrobial activity against Vibrio paraheamolyticus and Bacillus cereus.