Polyethylene degradation potential of Comamonas testosteroni PRC1 and Pseudomonas sp. PRC2 isolated from soil samples of plastic recycling centre, Lagos, Nigeria.
Keywords:
Polyethylene, utilization, recycle, biodegradationAbstract
Polyethylene polymer with its advantages of being strong, light-weighted, and durable, however, possesses disadvantages such as resistance to biological degradation and harmful to the natural environment. Solid waste related problems pose threat to megacities like Lagos. In this study, pooled soil samples collected randomly from a plastic recycling centre in Lagos were plated on Minimal Salt Medium with polyethylene as sole carbon source and screened for polyethylene-utilizing bacteria. The total dissolved organic matter was determined using the TOC titrimetric method and Fourier Transform infrared spectroscopy (FTIR) analysis was used to check the functional groups changes of the Low Density polyethylene (LDPE) material during the degradation period. Two bacterial strains Comamonas testosteroni PRC1 and Pseudomonas sp. PRC2 able to grow on polyethylene were used to degrade polyethylene. The persistence of the two isolates in the liquid medium after three months of incubation showed their ability to utilize the polyethylene material which served as carbon/ energy source for them. There was evolution of carbon (IV) oxide gas from the degradation experiment which was highest (55.50 ppm) at the 30th day with Pseudomonas sp. PRC2; the FTIR revealed disappearances and formation of new peaks in relation to the control sample. Alkenyl C=C stretch with wave numbers 1471cm-1 and 1647cm-1 disappeared in the polyethylene samples treated with Comamonas testosteroni PRC1 and Pseudomonas sp. PRC2 while carbonyl group with wave number 1716 cm-1 disappeared in the polyethylene samples treated with a combination of the two bacterial strains. The isolates showed degradative ability on the polyethylene (LDPE) material and thus can be used for biodegradation of polyethylene waste materials in the environment.