Biodegradation of polypropylene in presence of chromium mediated by Stenotrophomonas sp. and Lysinibacillus sp. isolated from wetland sediments

Abstract The advance of industrialization and globalization has been deteriorating nature by introducing components that compromise the holistic functioning of the environment. Plastics and heavy metals are widely integrated into our daily lives, and both production and consumption generate waste whose final disposal is not adequately managed. In the present work, two bioremediation mechanisms mediated by native microorganisms isolated from wetland sediments were studied. The presence of both contaminants has been reported at these sites. Bacteria were grouped according to their morphology and metabolic characteristics. The decisive criterion for choosing the bacteria for further tests was biofilm formation. This capacity is reported to be the initial step in the biodegradation of plastics. The best 5 bacteria that showed high biofilm formation were evaluated for their ability to biodegrade polypropylene and, in separate systems, their ability to grow at different chromium concentrations and to bioreduce the heavy metal to its harmless form. The three best-performing bacteria were selected to evaluate their growth in batch systems containing both pollutants. Polypropylene was biodegraded under the established conditions, and results indicated that two of the bacteria responsible for this degradation belong to the genus Stenotrophomonas and the third to Lysinibacillus. These genera have been reported as polypropylene biodegraders, but not in the presence of other contaminants. The results presented in this work may serve as a starting point for new studies that will allow the future application of native microorganisms from contaminated environments in bioremediation processes.