Soil burial biodegradation studies of starch grafted polyethylene and identification of Rhizobium meliloti therefrom

Abstract

Present study report on biodegradation of starch grafted polyethylene (PE), successfully synthesized by graft copolymerization method using benzoyl peroxide as the radical initiator. Biodegradable behavior of the grafted PE was ascertained by soil burial test. Percent weight loss was measured as a function of number of days and observed that it increased with increasing number of days. Microanalysis of the soil containing samples was carried out which substantiated the degradation. The biochemical tests was performed on the microorganism isolated from the soil in microanalysis, identified the organism as Rhizobium meliloti which helped in biodegradation of PE-g-Starch samples. The degradation was further confirmed by carrying out the physical characterization of the original samples and the degraded samples by scanning electron microscope (SEM) and thermogravimetric analysis (TGA). Hydrolysis of grafted samples, taken out from the soil after a specified number of days also corroborated in the findings, revealing continuous loss of weight with increasing number of days. Key words: Polyethylene, starch, graft copolymer, biodegradation.