Biodegradation of Polyethylene by Green Photosynthetic Microalgae

Conventional methods of polyethylene degradation including incineration, landfill and chemical treatment are lethal to the neighboring environment by causing hazardous effects on living organisms. A better solution for the complete degradation of polyethylene has not yet been formulated. However, to solve this global issue biological mode of polyethylene degradation may be evaluated and developed in the upcoming future. In this research investigation, microalgae like green algae, blue-green algae and diatoms were isolated from the domestic polyethylene bags dumped in the suburban water bodies and studied for its potency on deterioration of polyethylene. The dumped waste polyethylene bags were collected from three different sites of (Maduravoyal, Vanagaram and Poonamallee) Chennai, Tamil Nadu, India. Colonized mat of microalgae were isolated from the polyethylene sheets and the most dominant three different groups of microalgae were selected for the biological treatment of LD (low density) and HD (high density) polyethylene sheets. The most dominant microalgae were Scenedesmus dimorphus (Green microalga), Anabaena spiroides (blue-green alga) and Navicula pupula (Diatom). The T. S. (Transverse section) of polyethylene sheet has shown the proliferation of microalgae in both outer and inner sides of the polyethylene sheet and the erosion cum degradation can be seen obviously. The biological treatment of the selected microalgae on the LD and HD polyethylene sheets with their respective culture media resulted that the microalgae proliferated more on the LD than the HD polyethylene sheets followed by the highest percentage of degradation was obtained from Anabaena spiroides treatment (8.18%). Similarly, among the three microalgal groups treated over the LD polyethylene sheets. The scanning electron microscopical study reveals that the degradation was obviously evident in the treatment of LD polyethylene sheets using the microalga Anabaena spiroides (filamentous blue-green alga) and was found to grow feasibly rather than the other microalgae.