Antibacterial Activity of Carboxymethyl Chitosan Dialdehyde Starch Schiff Base and its Metal Complex

Carboxymethyl chitosan dialdehyde starch Schiff base (CMCDAS) and its metal complexes are synthesized by corn starch (St), sodium periodate, carboxymethyl chitosan, and metal ions (copper, zinc, nickel, silver), and are characterized by Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), thermogravimetric analyzer (TGA), energy dispersive spectroscopy (EDS), and X‐ray powder diffraction (XRD). The antibacterial activities of carboxymethyl chitosan dialdehyde starch Schiff base (CMCDAS) against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) increase according to their increasing nitrogen content, and the best minimum inhibitory concentrations (MIC) against E. coli and S. aureus are 30 mg mL−1, respectively. Furthermore, the minimum inhibitory concentrations (MIC) of the metal complexes (copper, nickel, silver, and zinc) against S. aureus are 7.50, 30, 30, and 1.88 mg mL, respectively; and against E. coli are 7.50, 15, 15, and 0.94 mg mL−1, respectively. In order to inhibit the growth of bacteria, a novel non‐toxic bacteriostat (CMCDAS) is synthesized by dialdehyde starch and carboxymethyl chitosan. CMCDAS can inhibit the growth of E. coli and S. aureus, and its metal complexes exhibit more obvious antibacterial effect.