Sergio Palacios-Mayorga, Ja
Exploring the Role of a Soil Microbial Consortium on the Biodegradation and Physical Alteration of Low Density Polyethylene Background: Our study is a contribution to the searching for microorganisms capable of degrading low density polyethylene. A microbial consortium was detected on low density polyethylene wastes buried under soil in a composting area of a Mexico City landfill known as “Bordo Poniente”. Methods: Photomicrographs of the microbial consortium by optical microscopy and scanning electron microscope (SEM) were taken at different times during the microbial film development in low density polyethylene; specific culture media, with polyethylene as the only carbon source, were used for strain isolation of bacteria, yeast and filamentous fungi; polyethylene degradation was evaluated by observing the physical alteration of this material in the SEM and by quantifying its weight loss when the polyethylene was used as a carbon source and incubated at different temperatures under shaking conditions at different pH. Results and conclusions: Photomicrographs of the microbial consortium by SEM, show a wide variety of species. It was possible to observe not only the shape of the microbial colonies but also the progressive development of a biofilm. The higher microbial degradation activity (18% in 60 days) was attained when cultures were incubated at 24°C under shaking conditions at pH 5.0. This is one of the more efficient degradations reported up to date. In addition, paper and wood degrading activity by the same consortium was estimated.