Carbon capture and utilisation to replace sugar-based fermentations in the biotechnology industry

Industrial biotechnology relies on agriculture to provide the input energy in the form of sugars for bacterial fermentations. Sugars are the carbon source and the energy source in these traditional setups. However, certain bacterial species are able to utilise carbon dioxide as their carbon source while relying on hydrogen gas as their energy source; these species are Hydrogen Oxidising Bacteria (HOB). The biochemical route exercised in HOB is the most efficient form of biological carbon fixation including photosynthetic algae.
Several companies are attempting to commercialise the use of HOB to make Single Cell Protein (SCP), which is sold as a proteinaceous feed ingredient. As a feed ingredient SCP has major environmental advantages over traditional feed proteins: it has a lower overall carbon footprint in addition to a dramatically lower land and water use. However, for full uptake of the technology commercially the product must have sufficiently high value to compensate for the input costs and relatively high capital costs of a commercial plant. Adoption of this technology benefits from the ramp up in interest and scaling of the hydrogen economy.
One particularly attractive route for improving the value of SCP is to co-produce other biological compounds of commercial interest such as dyes, flavourings, fragrances, or antioxidants. If these can be produced by the bacteria and extracted during downstream processing then the economics of SCP as a feed ingredient may become significantly more favourable. In the long-term the HOB will be engineered to compete technically with established species which currently make higher value compounds, but the HOB will have the advantage of using a hydrogen and carbon dioxide input stream rather than a sugar-based input.
Established strains in industrial biotechnology are highly adapted or engineered to maximise productivity. HOB have not been the target of these manipulations historically because of a lack of inherent predisposition as a production organism. However, the ability to grow on a mixture of carbon dioxide and hydrogen is a highly desirable trait because of the environmental benefits of this process compared to one dependent on agricultural products as an input stream. In addition, this ability is not one that can be easily transferred to the established production strains. A far simpler approach would be to transfer the relevant properties from the established production strains to the HOB.
Deep Branch has a library of HOB capable of growing on carbon dioxide. Within that library there are several strains for which a genetic toolkit has been developed which allows sophisticated genetic engineering to be performed.
Escherichia coli is the most widely used species for expressing high value proteins largely because of the genetic toolkit which has been developed for it. This project aims firstly to emulate many of the developments which have made E. coli the dominant species in industrial biotechnology primarily by engineering strong protein expression systems comprising promoters, ribosome binding sites, and powerful dedicated RNA polymerases.
Certain bacterial species are naturally well evolved to produce a given class of biological compound for instance an antibiotic. Other species would have evolved in such a way as to make them ideal candidates for the production of chemically dissimilar compounds such as dyes or flavours. To assess the suitability of the chosen HOB for the production of different classes of compounds a range of compounds will be chosen for expression. This will help to inform the most appropriate target for optimisation and deployment in a commercial setting.
Another goal will be to increase the efficiency of carbon capture via protein engineering. This will involve identifying the bottleneck in the biochemical pathway of carbon fixation and making a library of different versions of the bottleneck protein.

The proposed Centre will benefit the following groups

1. Students - develop their professional skills, a broad technical and societal knowledge of the sector and a wider appreciation of the role decarbonised fuel systems will play in the UK and internationally. They will develop a strong network of peers who they can draw on in their professional careers. We will continue to offer our training to other Research Council PhD students and cross-fertilise our training with that offered under other CDT programmes, and similar initiatives where that develops mutual benefit. We will further enhance this offering by encouraging industrialists to undertake some of our training as Professional Development ensuring a broadening of the training cohort beyond academe. Students will be very employable due to their knowledge, skills and broad industrial understanding.
2. Industrial partners - Companies identify research priorities that underpin their long-term business goals and can access state of the art facilities within the HEIs involved to support that research. They do not need to pre-define the scope of their work at the outset, so that the Centre can remain responsive to their developing research needs. They may develop new products, services or models and have access to a potential employee cohort, with an advanced skill base. We have already established a track record in our predecessor CDTs, with graduates now acting as research managers and project supervisors within industry
3. Academic partners - accelerating research within the Energy research community in each HEI. We will develop the next generation of researchers and research leaders with a broader perspective than traditional PhD research and create a bedrock of research expertise within each HEI, developing supervisory skills across a broad range of topics and faculties and supporting HEIs' goals of high quality publications leading to research impacts and an informed group of educators within each HEI. .
4. Government and regulators - we will liaise with national and regional regulators and policy makers. We will conduct research directly aligned with the Government's Clean Growth Strategy, Mission Innovation and with the Industrial Strategy Challenge Fund's theme Prosper from the Energy Revolution, to help meet emission, energy security and affordability targets and we will seek to inform developing energy policy through new findings and impartial scientific advice. We will help to provide the skills base and future innovators to enable growth in the decarbonised energy sector.
5. Wider society and the publics - developing technologies to reduce carbon emissions and reduce the cost of a transition to a low carbon economy. Need to ascertain the publics' views on the proposed new technologies to ensure we are aligned with their views and that there will be general acceptance of the new technologies. Public engagement will be a two-way conversation where researchers will listen to the views of different publics, acknowledging that there are many publics and not just one uniform group. We will actively engage with public from including schools, our local communities and the 'interested' public, seeking to be honest providers of unbiased technical information in a way that is correct yet accessible.