UTPE PEB · Ultrahigh-throughput protein evolution for polyethylene biodegradation
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2020-10-01 → 2023-03-15
- EU contribution
- €224,934
- Participants
- 1
- Scheme
- MSCA-IF
Lines connect the coordinator with its partners.
Results in brief
Ultrahigh-throughput protein evolution for polyethylene biodegradation
Polyethylene (PE) is the most abundantly produced plastic in the world, accounting for 30-40% of all synthetic polymers, with an annual global production of nearly 100 million tonnes in 2018. It is found in an extensive array of commonly used items, such as grocery bags, milk cartons and sponges. Due to its low economic cost, it is frequently adopted for single use functions, resulting in large quantities of PE waste. PE is durable, which is appealing for commercial purposes, but creates a major environmental problem as it can indefinitely persist in landfills after being discarded, with only around 10% of the total PE mass produced being recycled. PE degradation (both abiotic and biotic) occurs at a rate that cannot keep pace with current production, inevitably resulting in a build-up of plastic in the environment with detrimental consequences. The biodegradability of PE could be increased by enhancing natural biological processes through directed protein evolution. It has been known for nearly 50 years that degradation of PE is affected by microbes. Many studies have identified organisms capable of facilitating the degradation of PE, and in some cases the proteins responsible. However, these strains and enzymes are typically poorly characterized or inefficient. Directed protein can be used to improve the efficiency of enzymes, sometimes resulting in increases of reaction rates by many orders of magnitude. However, this impactful technology has yet to be applied to the challenge of polymer biodegradation. We have isolated bacterial strains capable of growth on Polyethylene as a sole carbon source, and have identified a protein element involved. This protein element can now be subjected to protein evolution campaigns to improve its activity.
Data: CORDIS, © European Union
Project objective
The build-up of plastic pollution is one of the most pressing environmental concerns. Polyethylene (PE), the most abundantly produced plastic polymer, can persist in nature for over a century. The microbial biodegradation of PE that has been observed is slow and inefficient. So far no effort has been undertaken to improve the efficiency of enzymes involved in the biodegradation of PE through directed protein evolution. Standard assays for measuring degradation rates are not sufficiently high-throughput to cover the sequence space required. I propose to use state-of-the-art protein evolution technology to overcome this problem in two ways. First, an ultrahigh-throughput microfluidics based approach, that can associate a given genotype with its phenotype in picoliter sized water-in-oil droplets, will be used to isolate the desired genotypes from a random mutagenesis library. Second, a novel assay for measuring polymer concentration within each droplet based on differential light scattering as the polymer is degraded will assay the PE degradation rate for a given enzyme. These techniques were developed in the research group of the proposed host, Dr. Hollfelder in the Department of Biochemistry at the University of Cambridge. Using these techniques, I will functionally express and evolutionarily optimise a range of PE degrading enzymes in genetically tractable host strains, creating a chassis to investigate the potential of microbial biodegradation as a solution to plastic waste. Secondments at the EBI, UCL and the SME Drop-Tech will convey practical skills in bioinformatics screens and droplet formation. The host group’s experience in enzyme biotechnology and directed protein evolution as well as its extensive modern facilities for microfluidics, next generation sequencing and flow cytometry will synergize with my personal research experience in synthetic, molecular and microbiology to find a multidisciplinary solution to the growing problem of plastic degradation.
Original text from CORDIS.
Participants
- THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE · CAMBRIDGECoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union