Studies on Biodegradation of Modified Polypropylene Sheets Using Pseudomonas Stutzeri under Aerobic Conditions

Abstract

The ability of bacteria to attack polymers was investigated in pure shake-flask culture studies. The mesophilic bacterium Pseudomonas stutzeri (MTCC number 2643) utilized Polypropylene (PP) and its blends with poly-L-lactic acid (PLLA) as the sole carbon and energy sources and degraded them. Incubation of PP and its blends with PLLA with Pseudomonas stutzeri for 60 days at 35°C, 120 rpm under aerobic conditions, reduced their weights. As the growth of microbes proportionally increased in synthetic media so it was predicted that the microbes were solely dependent on the polymer samples for its carbon source. Throughout the investigation, all the polymer samples were found to undergo quantitative and qualitative changes by bacteria. Biodegradation was observed in terms of their weight loss. PLLA was degraded maximum by Peudomonas stutzeri i.e upto 3.01% weight loss was observed followed by M-g-PP 80/6 i.e. upto 2.41%. PP100 had weight loss upto 1.25 %. The above data shows that blend of PP and PLLA blends show effective degradation than PP alone. The degradation results were confirmed by the scanning electron microscopy (SEM) analyses of the polymer samples. SEM micrographs showed the formation of patterns and cracks on the surface of the polymer samples evidencing a profound loss of structure.