Determining mechanisms and rates of microbial plastic biodegradation and the consequences for freshwater carbon cycling
EMSL Project ID
60397
Abstract
In recent years, plastic litter has been documented in widespread and diverse marine, freshwater, and even aeolian biomes. It is estimated that 4.8-12.7 million tons of plastics enters the ocean in a single year. While most early studies reported on plastics in marine systems, there has been a recent refocusing on freshwater systems, as most plastic enters watersheds via freshwater inputs and plastic concentrations in lakes and rivers have been reported as high, or higher, than in central oceans gyres. From both environmental health and resource and energy sustainability perspectives, there is global interest in understanding the fate of plastic waste in Earth’s waterways. The plastics industry has focused near-exclusively on abiotic processes of plastic weathering, such as UV and temperature exposure. Yet, from the moment they leave production lines, plastic products are subject to colonization by microbes. While there have been decades of reports of microbial isolates capable of weathering plastic surfaces, few studies have confirmed the mineralization of plastic-derived carbon by microbes and even fewer have resolved the mechanisms of plastic degradation, let alone the metabolic pathways of microbial degradation for environmentally relevant microbes and conditions. These knowledge gaps limit our ability to model and predict the fate of plastics in the environment, engineer systems to bioremediate plastics pollution and recover polymers for circular economies. In response, the DOE has developed a Plastics Innovation Challenge Draft Roadmap (Jan 2021), which proposes strategies for making the “domestic processing of plastic waste more economically viable and energy efficient” and specifically recommends the study of microbial systems for novel plastic-degrading enzyme and organism discovery, and leveraging complex microbiomes for polymer degradation to gain mechanistic understanding of polymer conversion and breakdown products. Aligned with this call, the work proposed here aims to (1) determine mechanisms and rates of polyethylene (PE) degradation by microbial isolates, (2) determine mechanisms and rates of PE biodegradable polymer (PAH, PLA) degradation by plastic-degrading consortia of enrichment cultures derived from natural freshwater and sediment communities, and (3) spatially map the cellular fate of PE in plastic biofilm matrices. To achieve these goals, we will leverage the many years of experience of our team in this field and the on-going lab-based culture work and field-based experiments, in combination with EMSL multi-omics, metabolic modeling, and advanced microscopy capacity and expertise.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2022-10-01
End Date
N/A
Status
Active
Released Data Link
Team
Principal Investigator
Team Members