Presentation Title:
It Takes a Village: Multiomics Reveals Diverse Taxonomies and Functions in Highly Enriched Polyethylene-Degrading Cultures

Formatted Title:

It Takes a Village: Multiomics Reveals Diverse Taxonomies and Functions in Highly Enriched Polyethylene-Degrading Cultures

Background/Objectives:

Polyethylene (PE) is a recalcitrant synthetic polymer composed of long, saturated hydrocarbon chains with inconsistent molecular weights and branching patterns. As such, PE presents a unique challenge and opportunity for bacteria - a highly energetic hydrocarbon which is entirely hydrophobic with no regular polymeric structural handles for enzymatic attack. However, PE is not unlike natural paraffin waxes that occur widely in both marine and terrestrial environments and presents nearly identical biodegradation challenges and opportunities – as such, a broad natural reservoir of PE-capable bacteria and enzymes is expected to exist. Enhanced biodegradation and upcycling of PE would reduce the environmental impact of this highly useful material.

Approach/Activities:

PE-degrading enrichments (with PE as sole carbon and energy source) were created from widely-varied environments and maintained over multiple generations. Metabolomics was employed to characterize PE degradation activity and byproducts. Deep meta-transcriptomics was employed on selected enrichment cultures under controlled experimental conditions to elucidate the unique taxonomies present and identify critical metabolic pathways employed during PE-degradation activities in comparison and contrast to related chemicals such as paraffin waxes and shorter-chain hydrocarbons.

Results/Lessons Learned:

Enrichment cultures generated from natural marine and groundwater systems showed extracellular metabolomic patterns consistent with oxidative cleavage of PE. Other omics data revealed that marine- and groundwater-derived systems remained taxonomically-diverse even after multiple enrichment cycles. Although taxonomies between the two systems were highly contrasted, intriguing functional parallels were observed, suggesting convergence of the systems towards suites of hydrocarbon oxidative activities. As hypothesized, similar functional patterns were observed when the cultures were provided paraffin wax as sole nutrition. Intriguing contrasting functions between cultures consuming PE rather than paraffin wax will be presented and discussed in addition to implications for applied bioremediation and upcycling.

Chiranjit Mukherjee

Affiliation

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C5.: Biodegradation and Upcycling of Plastics (Posters)