Novel Microbial Pd Catalysts from Waste for Sustainable Synthesis

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Biological Sciences

Abstract

Palladium (Pd) is a widely used catalyst in the modern chemical and pharmaceutical industries and is in short supply due to increasing global demand and supply chain pressures. Our recent studies have shown that the bacterium Desulfovibrio alaskensis can be used to recover Pd from waste for reuse as nanoparticle catalysts which work under energy-efficient manufacturing conditions. The Pd catalysts derived from the bacteria display enhanced chemical properties and can catalyze the formation of small molecules of use in the pharmaceutical industry. Here, we will (i) optimise the nanoparticles for this catalysis (ii) devise routes for their reuse and remanufacture so that the Pd can be continuously recovered and reused and (iii) expand the portfolio of reactions catalysed by the bacterially derived Pd and demonstrate catalysis with other metal nanoparticles.
This emerging biotechnology paves the way for the sustainable use of Pd, creating new circular pathways to improved Pd catalysts and replacing the current linear model of Pd catalyst use, which creates waste, is unsustainable and reliant on insecure supply chains.

Technical Summary

Palladium catalysed reactions are ubiquitous throughout the modern chemical and pharmaceutical industries. Yet this vital metal is classified as a critical material based upon both its supply risk and economic importance. Our recent studies have shown that the bacterium Desulfovibrio alaskensis can be used to remediate Pd salts and generate nanoparticle catalysts that can be used in green chemical synthesis. These biogenic Pd catalysts display enhanced chemical properties and catalyse the formation of small molecules of use in the pharmaceutical industry. Here, we will (i) optimise the nanoparticles for this catalysis (ii) devise routes for their reuse and remanufacture so that the Pd stays within a closed loop system and (iii) expand the portfolio of reactions reportedly undertaken with biogenic Pd and demonstrate catalysis with other biogenic platinum group metal nanoparticles.
Resulting in:
- Access to unique bacterial catalysts, tailored to the needs of different reactions
- Novel highly active bimetallic nanoparticles, applicable at low catalyst loadings
- Discovery of heterogeneous catalyst deactivation mechanisms
- Circular economy of Pd stream and widely applicable Pd upcycling system
- A roadmap to develop marketable catalysts for pharmaceutical processes
In summary, this emerging biotechnology paves the way for the sustainable use of Pd, creating circular pathways to Pd catalysts that do not currently exist and replacing the current linear model of Pd catalyst use.

Publications

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Dennis JA (2023) Biocompatible a-Methylenation of Metabolic Butyraldehyde in Living Bacteria. in Angewandte Chemie (International ed. in English)

 
Title Desulfovibrio genetic engineering tool (DeGET) 
Description An R-based application with a user-friendly interface for engineering Desulfovibrio species. The application uses an algorithm to look up genomic databases online and obtain genomic information. With one-click, it then designs parts for a CRISPR/Cas9 toolkit to edit the genomic DNA of Desulfovibrio species. 
Type Of Material Computer model/algorithm 
Year Produced 2023 
Provided To Others? No  
Impact This has enabled the high-throughput and cost-effective gene-knockouts in Desulfovibrio alaskensis, allowing further studies of metal metabolism. The application could be used to generate parts for whole-genome knockouts, allowing for systematic studies of Desulfovibrio genomes. 
 
Title LCA models of biogenic metal nanoparticle production and catalysis 
Description The work focused on assessing the sustainability of biogenic metal nanoparticle production and catalysis using Life Cycle Assessment (LCA) Life cycle inventory assessment was first performed to obtain data on reagents, quantities, waste products, energy usage and other parameters. The EcoInvent database in SimaPro was then used to construct LCA models of the production of biogenic metal nanoparticles by Desulfovibrio alaskensis, and their use as catalysts for green chemistry. Models were then constructed of chemical approaches for nanoparticle production and catalysis. 
Type Of Material Computer model/algorithm 
Year Produced 2024 
Provided To Others? No  
Impact The life cycle impact of biogenic metal nanoparticle production and catalysis was modelled using LCA. This indicated emissions hotspots associated with particular energy or material inputs. This then allowed more sustainable production methods to be rationally designed. 
 
Description Biological Upcycling of Metal Waste 
Organisation Johnson Matthey
Country United Kingdom 
Sector Private 
PI Contribution We initiated discussions with JM regarding the use of biotechnology in their metal operations, and JM agreed to provide us with samples of rare metal waste.
Collaborator Contribution Our industry partner is providing industrial waste containing precious metals.
Impact JM agreed for one of their senior staff members to contribute to a roadmap article on a biobased metal economy.
Start Year 2023
 
Description Sustainability assessment of biogenic metal nanoparticle production and catalysis 
Organisation University of Surrey
Country United Kingdom 
Sector Academic/University 
PI Contribution We have built life cycle inventories of biogenic metal nanoparticle production at multiple scales, and used these to construct life cycle assessment (LCA) models using the EcoInvent database on SimaPro. Key footprint hotspots were identified using the LCA models, resulting in new experiments being designed to test alternative production methods. This enabled the rational design of more sustainable production methods. We also constructed analogous models of biogenic metal nanoparticle catalysis to provide empirical evidence of sustainability.
Collaborator Contribution Our collaborator in Surrey provided input on identifying the LCA system boundaries, the collection of data, construction of the LCA inventory and models, and evaluation of the resulting models. We are also preparing to publish an article on the LCA of biogenic metal nanoparticle production and catalysis.
Impact LCA models of biogenic metal nanoparticle production and catalysis
Start Year 2023
 
Title Active nanoparticles from Desulfovibrio alaskensis 
Description This novel catalyst system uses metal nanoparticles produced by the bacterium Desulfovibrio alaskensis. These biogenic metal nanoparticles (BNP's) are highly active catalysts for metal catalysed cross-coupling reactions, outperforming commercially available catalysts and other biologically-supported metal nanoparticles. The catalytic activity of these nanoparticles is greatly enhanced by the use of biocompatible nanomicellar surfactants, enabling efficient cross-coupling reactions in water at 37 °C. Moreover, the benign nature of the catalyst system enables bi-functional catalysisin cascade systems incorporating the biohydrogenation of crosscoupling products. The heterogenous nanoparticle catalysts can be recovered from reactions using centrifugation and regenerated using bacteria. 
IP Reference PCT/GB2022/052538 
Protection Patent / Patent application
Year Protection Granted
Licensed No
Impact Currently international patent application has been submitted - not granted. Further research work reported in scientific publications
 
Title Catalyst system for cross-coupling 
Description A catalyst system for using biogenic metal nanoparticles as a catalyst for a new reaction under green conditions. 
Type Of Technology New Material/Compound 
Year Produced 2024 
Impact A new cross-coupling reaction has been demonstrated using the biogenic metal nanoparticle catalysts system. 
 
Description RSC Applied Catalysis for the Circular Economy 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact 30 minute presentation given at the Royal Society of Chemistry in London. Event was the RSC Applied catalysis for the circular economy. Presented on the use of metal catalysis with microbes, and received insightful questions. It was also an excellent opportunity to engage with representatives from two metals companies, resulting in one lead for a potential collaboration.
Year(s) Of Engagement Activity 2024
URL https://www.rsc.org/events/detail/77632/applied-catalysis-for-the-circular-economy-ii
 
Description RSC Circular Chemical Economy Summer School 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Attended a 3-day Circular Chemical Economy summer school in Newcastle, organised by the RSC. Fascinating talks on the use of chemistry and biology to manage waste, plastic pollution and create value-added chemicals via chemical/biological upcycling. Involved a workshop on the use of OpenLCA software for life cycle assessments.
Year(s) Of Engagement Activity 2023
URL https://www.rsc.org/events/detail/76880/circular-chemical-economy-summer-school
 
Description SULSA delegation visit to Germany 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact PDRA attended a week-long delegation visit to Rhineland Palatinate (RLP) in Germany with representatives from 11 out of 13 universities in Scotland. The delegation visit was organised by the Scottish Universities Life Science Alliance (SULSA), universities in RLP, and the RLP state government. The PDRA delegate represented the Environment, Bioeconomy and Sustainability Strategic Group.

Delegates presented broad research overviews for their institutions, and academics at RLP universities presented their research to develop collaborative opportunities with Scottish universities. The delegation visited the German Research Centre for AI, Boehringer-Ingelheim and TRON (the Translational Oncology research centre responsible for BioNTech's vaccine technology). The visit was also a chance for delegates to engage with universities across Scotland, and to develop new intra- and inter-national relationships.
Year(s) Of Engagement Activity 2024
 
Description UK-India Critical Minerals workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact The workshop was organised to gain research innovation and policy insights in the UK and India on critical mineral exploration and extraction and opportunities in both the UK and India and to create a UK-India community of academics, innovators, investors, and companies to address challenges and help identify best practices and commercial opportunities. One focus was to explore gaps and opportunities for future research and innovation work streams between both countries and Identify at least 2 grand challenges for Future Funding.
Year(s) Of Engagement Activity 2024