While several research groups are utilizing purified enzymes to break down postconsumer PET to the monomers TPA and ethylene glycol to produce new PET products, here, we present a group of five soil bacteria in culture that are able to partially degrade this polymer. To date, mixed Pseudomonas spp. and Bacillus spp. biodegradation of PET has not been described, and this work highlights the possibility of using bacterial consortia to biodegrade or potentially to biorecycle PET plastic waste.
Here, we report the annotated draft genome sequences of three Pseudomonas spp. and two Bacillus spp. that, as consortia, degrade polyethylene terephthalate plastic. Improved microbial degradation of plastic waste could help reduce the billions of metric tons of these materials that currently exist in our environment.
Bioaugmentation is a possible remediation strategy for the massive amounts of plastic waste in our oceans and landfills. For this study, soil samples were collected from petroleum polluted locations in the Houston, Texas area to isolate microorganisms capable of plastic degradation.Bacteria were propagated and screened for lipase activity, which has been associated with the bacterial degradation of some plastics to date. We identified three lipase-positive Pseudomonas species, and Bacillus cereus as part of two consortia, which we predict enhances biofilm formation and plastic degradation. Lipase-positive consortia bacteria were incubated alongside blank and E.coli controls with UV-irradiated polyethylene terephthalate (PET), high-density polyethylene (HDPE), or low-density polyethylene (LDPE) as sole sources of carbon. Surface degradation of PET plastic was quantified by changes in molecular vibrations by infrared spectroscopy. The bacteria formed biofilms on PET, observed by scanning electron microscopy, and induced molecular changes on the plastic surface, indicating the initial stages of plastic degradation. We also found molecular evidence that one of the Pseudomonas isolates degrades LDPE. To date, lipase positive Pseudomonas spp. degradation of PET has not been well described, and this work highlights the potential for using consortia of common soil bacteria to degrade plastic waste.
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