Biodegradation of starch-polyethylene films in soil and by microbial cultures

Among the starch-containing low density polyethylene films tested for biodegradation, films containing 30% starch showed maximum biodegradation leading to a loss of 6.3% in weight and 84.5% starch upon burial in a soil-compost mixture for 48 weeks. Biodegradation of this film was accelerated by incubation with an acclimatized culture in a shake-flask showing 11.2% and 68.9% loss of weight and starch respectively, after only 6 weeks. FTIR and C-13 NMR analysis revealed that the loss of starch in biodegraded films is accompanied by structural changes in polyethylene in terms of reduction in the peak area of polyethylene backbone and short chain branches.