Biodegradation of LDPE (low density polyethylene) using bacterial strain

Abstract

The applications of polyethylene are enormous and they are popular because of their relatively low cost, lack of difficulty in manufacture, adaptability and durability. In the past decade, the increase in the utilization of plastics and the accumulation of polyethylene in the environment all around the globe has drawn the attention of environmentalists and scientists. The plastic materials are commonly derived from petrochemicals extracted from coal and natural gas. They are produced in a wide range in synthetic, semi synthetic organic polymers. The degradation of LDPE film was determined by residual dry weight loss of the LDPE films. The potent strain showed 42.5% degradation ability in 90 d. Degradation of LDPE results in the breakdown of the polymer backbone chain producing CO2 which was checked by gravimetric analysis. Enzyme kinetic studies showed the production of three ligninolytic extracellular enzymes- lignin, laccase and manganese peroxidase by bacterial strain AJ01 in LDPE degradation. Degradation of LDPE strips followed first order kinetics model with a rate constant (R2) of 0.9783 d-1. Estimation of protein from post treated LDPE using bacterial isolate showed a total concentration of 0.440mg/0.1mL and 0.703mg/0.2mL. LDPE degradation was confirmed by using analytical techniques such as SEM which showed changes in the surface topology of LDPE strips and FTIR analysis showed changes in complex chemical structure of LDPE post 90 d of degradation using microorganisms thereby reducing carbonyl index (CI) value.