Abstract

A COMPARATIVE STUDY ON BIODEGRADATION ASSAY OF DIFFERENT TYPES OF PLASTIC WASTE USING VARIOUS MICROORGANISMS

Sasikumar J.*, Mohamed Halick A., Nadanakumar K., Sanjay Kumar T., Saravanan N., Ramesh Babu N. G. and Parvathy S.

ABSTRACT

Plastics are omnipresent. They play an important role in packing of food materials, Fast Moving Consumer Goods (FMCG), drinking water bottles, insulating electrical wires, etc. But plastic waste causes pollution in one or many forms and releases toxic poisonous gases when it is improperly disposed off by means of incineration. One of the best and most widely accepted method for disposal of plastic wastes is using microbes to breakdown them into non-toxic form. The present study aims to culture microbes in nutrient rich test medium and to compare the biodegradability of pretreated plastic waste selected for assay. It includes Poly Ethylene Terephthalate (PET), High Density Poly Ethylene (HDPE), Low Density Poly Ethylene (LDPE (S1)) and Low Density Poly Ethylene (LDPE (S2)). Pre-treatment was carried out by exposing the selected plastic waste to sun light and UV light for a period of 72 hours alternatively followed by chemical treatment. Initial thickness and weight of plastic were measured by using air wedge apparatus (as 0.25 mm, 25 μm, 50 μm and 40 μm,) and weighing balance (as 63 mg, 50 mg, 37 mg, 28 mg) respectively. Test medium with variable carbon, nitrogen and mineral salt composition increases the metabolism of microbes responsible for the production of enzymes thereby resulting in increased degradation of plastics measured by weight loss method. Maximum weight loss percentage was shown by Trichoderma viride and was calculated as 13 %, 30 %, 24 %, and 32 % for PET, HDPE, LDPE (S1) and LDPE (S2) respectively. Fourier Transform Infra-Red (FTIR) spectrometric analyses has shown that various peaks corresponding to end products formed as a result of bond scission by biodegradation.

Keywords: Plastic waste (PET, HDPE, LDPE (S1) and LDPE (S2)), Biodegradation, FTIR.