Preparation and antibacterial activity of a cellulose-based Schiff base derived from dialdehyde cellulose and L-lysine

A cellulose-based Schiff base was synthetized via condensation reactions of dialdehyde cellulose (DAC) with l-lysine (Lys) and its antimicrobial activity was evaluated. The results of amino acid analysis, viscosity measurement, FTIR spectra, X-ray diffraction patterns, and solid-state cross-polarization (CP)/magic angle spinning (MAS) 13C-NMR indicated that the cellulose-based Schiff base (DAC-Lys) between DAC and Lys were formed. Thermogravimetric analysis (TGA) results showed that as compared with DAC, the DAC-Lys had diminished thermostability. When l-lysine content in DAC-Lys was 9.93 ± 0.35 g/100 g sample, the DAC-Lys exhibited high antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Salmonella typhimurium, and their MIC values were 7.5, 3.75, 7.5 and 3.75 mg/mL, respectively. The cellulose-based Schiff base, with good antibacterial activity, non-toxicity, and permissible biocompatibility, might be potential additives in papermaking for the introduction of antibacterial agents.