Carboxymethyl chitosan zinc supplement: Preparation, physicochemical, and preliminary antimicrobial analysis

Abstract Enrichment of carboxymethyl chitosan with zinc provides alternative means of producing aqueous soluble chitosan-based material with antimicrobial and essential trace element properties. The change in FTIR spectra of bands at 3,266 and 3,106 cm−1 of the carboxymethyl chitosan from a strong to a weak band confirmed the formation of carboxymethyl chitosan zinc supplement. From the EDX result, elemental composition of carboxymethyl chitosan is 52.89% carbon, 39.34% oxygen, 0.38% sodium, 0.54% aluminum, 2.61% calcium, and 4.19% aluminum, while carboxymethyl chitosan zinc supplement recorded 49.55% carbon, 40.40% oxygen, 1.28% sodium, 2.37% nitrogen, and 6.40% zinc. The XRD spectrum of carboxymethyl chitosan showed a lower peak intensity as compared with that of its zinc supplement. The antibacterial activities showed that carboxymethyl chitosan zinc supplement was active against all tested bacterial having recorded 6.00, 5.00, 3.00, 7.00, and 6.00 zone of inhibition (mm), respectively, against Staphylococcus aureus, Bacillus cereus, Pseudomonas syringae, Pseudomonas aeruginosa, and Escherichia coli, while carboxymetyhl chitosan was active only against S. aureus (6.00 mm). Antifungal activities revealed that carboxymethyl chitosan zinc supplement had higher zone of inhibition (mm) 42.22, 40.00, 37.78, and 48.88 mm against Collectotrichum falcritum, Rhzoctonia solani, Colletotrihum lindematianum, and Trichhoderum rubrum, while carboxymethyl chitosan recorded 26.66, 18.88, 15.88, and 22.22 respectively. The combination of aqueous solubility and antimicrobial activities of the zinc-supplemented carboxymethyl chitosan prepared should make it a good replacement for carboxymethyl chitosan in various industrial applications like food, cosmetics, biomedical, and pharmaceutical.