Fabrication of bio-based polyamide 56 and antibacterial nanofiber membrane from cadaverine

A green bioprocess for the fabrication of nanofiber membranes from the biomaterial polyamide 56 (PA56) via electrospinning was proposed. Cadaverine, as the precursor of PA56, was first produced from recombinant Escherichia coli using the whole-cell biotransformation of lysine. PA56 was then fabricated by mixing adipic acid with purified cadaverine obtained from solvent extraction and distillation. The thermal properties of the fabricated PA56 are as follows: a melting point of 250 °C, a crystallization point of 220 °C, and a degradation temperature of 410 °C. A PA56 nanofiber membrane (PAM) was further prepared via electrospinning. Dyed membranes (P-Dye) were obtained by the reaction of Reactive Red 141 dye with the amino group of PAM. Poly-(hexamethylene biguanide) (PHMB) was attached to the P-Dye to create P-Dye-PHMB. On the other hand, PAM with alginate, used to facilitate PHMB attachment (P-Alg-PHMB), was compared with P-Dye-PHMB in terms of antibacterial activity against pathogenic strains of E. coli and Pseudomonas putida. P-Alg-PHMB showed excellent antibacterial efficiency for E. coli (97%) and P. putida (100%). The proposed bioprocess can be used to fabricate novel membranes for biomedical applications and functional textiles.