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The global utilization of single-use, non-biodegradable plastics, such as bottles made of polyethylene terephthalate (PET), has contributed to catastrophic levels of plastic pollution. Fortu- nately, microbial communities are adapting to assimilate plastic waste. Previously, our work showed a full consortium of five bacteria capable of synergistically degrading PET. Using omics approaches, we identified the key genes implicated in PET degradation within the consortium’s pangenome and transcriptome. This analysis led to the discovery of a novel PETase, EstB, which has been observed to hydrolyze the oligomer BHET and the polymer PET. Besides the genes implicated in PET degradation, many other biodegradation genes were discovered. Over 200 plastic and plasticizer degradation-related genes were discovered through the Plastic Microbial Biodegradation Database (PMBD). Diverse carbon source utilization was observed by a microbial community-based assay, which, paired with an abundant number of plastic- and plasticizer-degrading enzymes, indicates a promising possibility for mixed plastic degradation. Using RNAseq differential analysis, several genes were predicted to be involved in PET degradation, including aldehyde dehydrogenases and several classes of hydrolases. Active transcription of PET monomer metabolism was also observed, including the generation of polyhydroxyalkanoate (PHA)/polyhydroxybutyrate (PHB) biopolymers. These results present an exciting opportunity for the bio-recycling of mixed plastic waste with upcycling potential.
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Enrichment of Microbes Potentially Degrading Polyethylene Using a Microcosm Approach
Plastic pollution is a worldwide phenomenon with concerning effects on the biosphere and particularly on the marine environment. Biodegradation is considered an environmentally friendly alternative to combat the increasing quantities of plastic pollutants where different microbial sources are tested for plastic degradation potential. In this project, a microcosm approach was used as an enrichment method for marine microbes degrading polyethylene. Pieces of low-density polyethylene (LDPE) and highdensity polyethylene (HDPE) previously deployed in ocean water have been explored as a source of microbial biomass. This source plastic was added to a synthetic medium containing sterilized pieces of LDPE and HDPE as the sole carbon source and were incubated for extended periods (32-86 days) in the laboratory to promote growth of microbes that can degrade plastic. Biodegradation of polyethylene was confirmed by dry weight measurements and Fourier Transform Infra-Red (FTIR) spectroscopy. For both LDPE and HDPE a significant reduction in dry weight was observed. FTIR analysisshowed peaks suggesting oxidative changes in polyethylene’s chemical composition. In summary, the microcosm approach can be considered a viable approach for enrichment of plastic-degrading marine microbial populations.
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- Award ID(s):
- 1832545
- PAR ID:
- 10296691
- Date Published:
- Journal Name:
- Fine Focus
- Volume:
- 6
- Issue:
- 1
- ISSN:
- 2381-0637
- Page Range / eLocation ID:
- 84 to 101
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.33043/ff.6.1.84-101
