Hydrolytic Degradation of Nylon-6 by Pseudomonas aeruginosaHE858284 Isolated from Solid Waste Dumpsites in Lagos State, Nigeria

Abstract

Polyamide-6 (also known as nylon-6) is one of the biodegradable-resistant synthetic polymers used in the manufacturing of commodity plastic materials. The environmental effects of the persistence of this material in landfill pose a global problem of disposal system. Knowledge of the microbial pattern of interaction with this plastic will provide the biological resources and scientific basis for the development of sustainable disposal and treatment method.

Pseudomonas aeruginosa (HE858284), one of the bacterial isolates from Solid Waste dumpsites that were screened for their ability to utilize ?-caprolactam (the monomer of the nylon-6) as a sole source of carbon and nitrogen for growth and identified base on 16SrDNA gene sequences was tested for nylon-6 degradation. Intermediate products in the culture medium were monitored using High Performance Liquid Chromatography (HPLC) while biodegradation of the nylon-6 was monitored using Fourier Transmittance Infrared Spectroscopy (FTIR), average number molecular mass (M_n) and weight loss. An un-inoculated experiment served as the control. Data obtained were analysed using ANOVA.

The HPLC analysis of the culture supernatant revealed the presence of 6-aminohexanoic acid, ?-caprolactam and some un-identified oligomers as the degradation products of the nylon-6 fibre. The changes observed in the FTIR spectra of different functional group confirmed the effect of microbial degradation of the nylon-6 fibre. The degradation potential of 12.82 % reduction in M_n and 5.23% weight loss within 90 days was recorded in this Pseudomonas aeruginosa (HE858284).These changes were found to be significant at p = 0.05.

This ability in the bacteria isolate from solid waste dumpsites will serves as baseline information for the bio-treatment of the nylon-6 polymer.

Key words: Nylon-6, ?-Caprolactam , Solid waste dumpsite, Microbial degradation, 16SrRNA.