Understanding and exploiting biological metal-nanoparticle synthesis for metal recovery

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

Abstract

There is increasing concern over environmental copper levels, their toxicity and their adverse effects on humans and wildlife. The environmental quality standard of copper in groundwater in the UK is set low, at 1-28 ug/l, to balance these risks against the interests of industry. Consequently, the currently allowed environmental level of copper effectively pitches the key Scottish industry of salmon fishing against another - the spirits industry, as whisky, vodka and gin production involve a universal step of distillation in copper pot stills. Soluble copper is required in the distilling process as it prevents sulphur-containing compounds from distilling with the alcohol, which would give it an aroma of bad eggs, so a simple change to the material from which the stills are made is not an option. This dissolved copper is then found in the waste, and not the whisky, in concentrations high enough to be toxic to living organisms. Therefore, it is necessary to treat the waste before it can be used as animal feed, fertiliser or released into the environment.

The whisky industry has invested heavily in research to develop an effective method for removing toxic material from the waste of the whisky making process. Current treatments include chemical and physical methods that are expensive and have significant limitations. Cheap and effective treatment methods for copper contaminated waste still need to be developed and employing bacteria for the recycling of such contaminants may provide the solution, allowing the whisky industry to continue its expansion without adverse environmental consequences.

The biological transformation of copper ions to stable copper nanoparticles may provide a cost-effective biological solution for the treatment of distillery coproducts. This biotransformation of metal ions occurs naturally within some bacteria with the formation of solid metal nanoparticles outside of the bacterial cell. Our previous work has shown that distillery coproducts are an excellent nutrient source for our chosen bacterium and that the copper ions in distillery coproducts can be biotransformed to nanoparticles at the same time.

This application requests funding to improve the efficiency of this process to allow its future use on a industrial scale.

Technical Summary

Metals have a finite supply, thus metal scarcity and supply security have become worldwide issues. To solve such a global challenge, we have to ensure that we do not drain important resources by prioritizing the desires of the present over the needs of the future. Thus we need to move to a circular, more sustainable economy where we use the resources we have more wisely. One of the founding principles of a circular economy is that waste is an unused feedstock; that organic and inorganic components can be engineered to fit within a materials cycle, by the design, engineering and re-purposing of waste streams. Biological nutrients are non-toxic and can be composted, whereas technical nutrients can be designed to enable their reuse with minimal energy.

However, what if it was the 'compost' itself that provided energy to designed microbes that were then able to engineer the reuse of materials? That is the aim of this proposal. To use the new tools and techniques provided by advances in biology to engineer a bacterium with the ability to recycle metals from waste streams.

Certain bacteria have the ability to reduce metal cations and form precipitates of zero-valence, pure metals, as part of their survival mechanism to defend against toxic levels of metal cations. We will use a modular approach, commonly used in Synthetic Biology, to enable us to design, build and test methods to enhance the bioproduction of these high-value metal nanoparticles. We will also compare this method to a more traditional strain enhancement approach and use the data provided through proteomics to further inform design. Thus we will provide the next step towards a biological waste treatment method with high value metal recovery.

Planned Impact

This project will address the important challenge of remediating contaminated wastes to recover materials for future use and economic gain.

Industrial Impact: Diageo plc. is a global leading company in beverage alcohol. Having promised not to increase the production of waste while still planning ambitious expansion the company has effectively committed to around a 50% reduction in waste. It is therefore seeking to invest in research that may provide new ways to remove contaminating copper ions from its co-products, allowing their use as animal feed and fertilizer, with the recovery of valuable copper. Importantly, Diageo is a committed member of the Scotch Whisky Association and sees the development of such a technology as vital for the industry rather than as a USP for itself and would therefore share such a technology to further promote the iconic, high quality product of Scotch Whisky worth £4.23bn in annual exports. In addition to whisky, gin and vodka require similar distillation steps in copper pot stills, producing similar contaminated co-products, and thus the adoption of new bioremediation technology would have manufacturing impact outside of Scotland.

CuNPs are of interest in the electronics field, especially the market of conductive inks, which is expected to grow to $2.4 billion by the end of this year. Currently, conductive inks used for printed electronics are based on silver particles. However, 80% of the cost of the silver inks is the metal and this price is unpredictable. Research into alternatives has led to silver-coated copper nanoparticles. They use less than 10% silver loading; however the processing costs are higher, which means savings of only 10-15% on standard silver inks. Therefore, there is a new market arising for CuNPs (currently $8500 per kg, compared with approximately $17 for micron size particles) and the substantially lower costs of bioproduction suggests that they might offer a viable and cost-effective alternative to the chemically synthesized particles currently in use.

Our abilities to manipulate bacteria in combination with their ability to synthesise nanoparticles could provide access to a host of novel nanoparticles. While we cannot predict their properties at this stage it is possible that they may be similar to those of critical metals already in use. This would allow the novel biogenic nanoparticles to replace scarce materials, which have prices dictated by countries outside of the UK, and thus ensure resource security.

Public and Social Impact: The environmental quality standard for copper in groundwater in the UK, is set reassuring low and new bioremediation technologies would not benefit public health as alternatives are available. However, the resource efficiency KTN estimates that world wide mining activities are responsible for 5% of global carbon dioxide emissions, consume limited fossil fuel resources and produce other damaging 'greenhouse gases', recovery of metals would reduce the burden on mining and its environmental impact.

Economic Impact: The industrial impacts described will produce economic benefits to Scotland and the UK and concurrent social benefits to some of the less affluent areas of the UK, creating employment and reducing healthcare needs, which in turn leads to economic benefits at a national and international level. The recovery of materials from waste streams has obvious economic benefits and the development of new process routes for the production of lower cost and/or higher performance metal nanoparticles may contribute towards wealth generation in a number of possible sectors.

Policy Makers: Impact on policymakers on future technology options in: contaminated waste remediation (e.g. DEFRA); eco-friendly/economic production routes for nano-materials (BIS and DEFRA); advancing biotechnology/synthetic biology in the public interest and in the development of a range of high-value products that rely on nanoparticles (BIS, DH and DECC).
 
Description The work involved in this project was successful in creating a modularised expression vector for a non-model bacterium along with a library of promoters, ribosomal binding sites and reporters. A range of native reporters have also been characterised. The modular vectors created were used as a platform for the insertion and subsequent overexpression of genes hypothesised to be involved in the production of copper/silver nanoparticles. Overexpression of a number of genes showed no difference in the number of copper nanoparticles produced or their size and shape. A protein hypothesised to be important in the copper/silver nanoparticle pathway was successfully cloned in E. coli, expressed, purified and tested for binding affinity against various metals of environmental importance including copper and silver.
The directed strain enhancement work that involved growing the non-model bacterium in high copper concentrations and whisky distillery co-products has yielded a strain that is more resistant to high copper ion concentrations. This strain and others resulting from the work are currently being investigated in order to discover the beneficial genetic mutations leading to higher copper resistance and potentially greater copper ion conversion to nanoparticles.
Exploitation Route This project in still underway.
The tools and non-model organism handling experience developed within the course of this work are being used within an industrial research collaboration.
Their wider application and routes to commercialisation were explored through a BBSRC pathfinder award.
Sectors Agriculture, Food and Drink,Environment,Manufacturing, including Industrial Biotechology

 
Description Lignin-Based Metallic Nanoparticle Composites as Anti-Corrosion Agents
Amount £100,000 (GBP)
Funding ID CDE100662 
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 07/2016 
End 06/2017
 
Description BBC Arabic's 4Tech interview 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact The 4Tech programme, on BBC Arabic, focuses on technology and the advances it can bring. A research in my lab and I were both interviewed for a feature to describe how we could use bacteria to capture and recover metals from waste.
Year(s) Of Engagement Activity 2018
URL https://www.youtube.com/watch?v=p2f2NUwKi30
 
Description Bang Goes The Borders 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact A workshop was set up to explain different aspects of molecular biology and our research in the lab. The primary audience was school children between the ages of 5 and 14 with parents also partaking in the workshop. Many regional schools attended the event which was held at the St. Mary's school in Melrose.
Year(s) Of Engagement Activity 2017
URL http://www.shintonconsulting.com/bgtb/
 
Description Bang Goes The Borders 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact A workshop was set up to explain different aspects of molecular biology and our research in the lab. The primary audience was school children between the ages of 5 and 14 with parents also partaking in the workshop. Many regional schools attended the event which was held at the St. Mary's school in Melrose.
Year(s) Of Engagement Activity 2016
URL http://www.shintonconsulting.com/bgtb/
 
Description Bang Goes The Borders 2018 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact A workshop was set up to explain different aspects of molecular biology and our research in the lab. The primary audience was school children between the ages of 5 and 14 with parents also partaking in the workshop. Many regional schools attended the event which was held at the St. Mary's school in Melrose.
Year(s) Of Engagement Activity 2018
 
Description Bang Goes the Borders activities 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Organised and demonstrated research-related activities for Bang Goes the Borders event in Melrose, Scottish Borders. We discussed our research and its impact with both school pupils and their families.
Year(s) Of Engagement Activity 2017
 
Description Cafe Sci 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Presented my research in an publicly-accessible manner to Cockermouth Café Scientifique
Year(s) Of Engagement Activity 2018
 
Description Cafe Sci 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Invited biotechnology debate panellist at a Cafe Sci event held as part of the Glasgow Science Festival, hosted by the Royal Society of Biology and the Biochemical Society. The event was publicised, tweeted live and later reported on by the Royal Society of Biology and the Biochemical Society.
Year(s) Of Engagement Activity 2016
URL http://www.gla.ac.uk/events/cafescientifique/events/canwegivenewbiotechthegreenlight/
 
Description Invited speaker to 'Curious Minds' lecture series 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Third sector organisations
Results and Impact Presented my research in an accessible way to the Perthshire Society of Natural Science. A regional learned society.
Year(s) Of Engagement Activity 2018
 
Description Metals in Biology Meeting in Durham, England 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The meeting involved a series of oral presentations with networking opportunities throughout on all topics related to metals in biology. I presented a poster presentation which got nominated for the poster prize, and had the opportunity to speak to and exchange ideas with many attendees and other researchers working on the same field.
Year(s) Of Engagement Activity 2016
URL http://prospect.rsc.org/MiB_NIBB/
 
Description Oral Presentation in ECB 2016 Conference in Krakow, Poland 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The purpose of the presentation was to communicate the project's goals and outcomes to date. The presentation sparked questions from the audience with a number of attendees approaching me after the talk to discuss the research.
Year(s) Of Engagement Activity 2016
URL http://ecb2016.com/
 
Description SynBioBeta Activate! event in Beijing, China 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This event provided the opportunity to hear the latest synthetic biology advances, new technologies and applications. It allowed me to network with industry experts and academics in similar fields. During the meeting I met with a number of researchers and communicated each others' research.
Year(s) Of Engagement Activity 2016
URL http://synbiobeta.com/news/china-growing-synthetic-biology-ecosystem/
 
Description Synthetic biology debate panellist 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Invited synthetic biology debate panellist at the Linnean Society of London, hosted by the London Evolutionary Research Network. This was a public debate, organised by a learned society.
Year(s) Of Engagement Activity 2018
 
Description UN Biodiversity Conference 2018 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact The Royal Society, the African Academy of Sciences and the Wellcome Trust organised an event on synthetic biology at the Conference of Parties to the UN Convention on Biological Diversity. This event informed conference delegates about synthetic biology as they debate how these technologies should be regulated. The Convention on Biological Diversity's (CBD) has been in discussions on synthetic biology since the 2016 Conference of Parties (COP) and there was another effort at this year's COP to agree proposals that would serve as a moratorium on gene drive research and possibly have wider implications for synthetic biology.
This event at COP was to provide delegates with an opportunity to hear about synthetic biology research and governance in a range of countries and contexts.
Year(s) Of Engagement Activity 2018