BIODEGRADATION OF PLASTIC DISPOSABLE PLATES AND CUPS WITH SOIL MICROORGANISMS

Abstract

Plastics are synthetic or semi-synthetic polymerized products which is used across many industries. Due to the increasing global consumption, natural resistance to degradation, and their accumulation in the environment of plastics this study was conducted to reduce the effects of this ecological threat. Soil samples were collected from Ondo State Waste Management Authority’s dumpsite along Igbatoro Road Akure at depths of 15cm, 30cm, 45cm, 60cm and 70cm using soil auger. The microbial genera found associated with Akure Dumpsite were identified as two Gram positive and six Gram negative bacteria, and five fungal species. The species that were predominant were Pseudomonas, Bacillus, Micrococcus and two species of Aspergillus (Aspergillus niger and Aspergillus flavus).The bacterial isolates from the soil samples were screened using minimal salt medium containing polyethylene powder as carbon and nitrogen source and three bacterial isolates namely Bacillus subtilis, Pseudomonas aeruginosa and Pseudomonas putida utilized polyethylene as its sole nutrient source. Biodegradation of polyethylene disposable plates and cups was analysed after 4, 8 and 12 weeks of pre-treatment in shaker cultures at 300 C and 400C. Weight loss measurement of the plastic was used to determine the rate of degradation (% weight loss) and Fourier Transform Infrared Spectroscopy (FTIR) was used to monitor the degradation of the Plastic. The highest weight loss observed was 72% by Pseudomonas putida after 12 weeks with the lowest being 22% Bacillus subtilis after 12 weeks. The changes in the FTIR spectra of different functional groups confirmed the effect of biodegradation on the plastic. The ability of the bacterial isolates in this study to degrade the amide bend, ethylene alkyl group and isocyanate stretch of the polyethylene material therefore reveal the potential of the isolates in biodegradation measures to combat environmental pollution by polyethylene plastics