Grow-Your-Own Composites: Programming Diverse Material Properties for Defence into Engineered Bacterial Cellulose

Bacterial cellulose is a strong, ultrapure form of the biomaterial nanocellulose, which is naturally made in large amounts by several species of Acetobacter bacteria including K. rhaeticus. Bacterial cellulose is cheap to produce, has desirable purity, high crystallinity and tensile properties and does not contain other impurities like those found in plant cellulose. It is mouldable, biocompatible and capable of storing water over 90% of its total weight, and has found numerous commercial applications in medical wound-dressings, high-end acoustics, and many other diverse products.

In this proposal, we plan to build on our recent success guiding the Imperial College 2014 iGEM team in developing genetic manipulation methods and a synthetic biology toolkit for K. rhaeticus, the first toolkit of note for bacteria that produce cellulose in high yields. Our vision is to use synthetic biology methods to modify the production of bacterial cellulose from K. rhaeticus so that the bacterial cultures now produce programmable cellulose composites that have diverse and highly-desired material properties, ideally for defence applications. By using our synthetic biology tools and expanding this toolkit with further features such as genome editing and light-based control, we will be able to alter and control bacteria at the DNA level so that they now can be made to secrete modified bacterial cellulose with different bulk properties such as altered hydrophobicity. We will also use our toolkit to get our growing bacteria to produce interwoven mixtures of bacterial cellulose and other biomaterials such as bioplastics, functional proteins (e.g. enzymes) and protein polymers (e.g. curli fibres and silks). The result will be a variety of biosynthesised nanocellulose composites, likely to have valuable material properties that improve the strength and ductility of materials fabricated with this substrate, without increasing the weight and cost significantly further. Combining our team's considerable expertise in synthetic biology, composite engineering and blast research, we will together develop methods to safely convert these bacterial cellulose composites into lightweight layered composite materials and into advanced aerogels that match the material properties desired for defence applications in protection and shock absorption and more. We will test the mechanical properties of our new biosynthesised composites and use this to feedback to improved second-generation designs. Our project brings together Synthetic Biology and Advanced Materials, two of the UK's Eight Great Technologies, and will lay the foundations for using DNA-based engineering of cells to produce advanced biomaterial composites with many diverse and valuable future applications.

The proposed work will take foundational science in bacteria and composites right through to applications that yield new material products. As such it is an exemplar interdisciplinary project designed to produce advanced improved products at lower cost, and will benefit academic biotechnology and engineering science, DSTL, the UK/EU engineering sector, and UK industrial manufacturing throughout the value chain. The project links together both Synthetic Biology and Advanced Materials - two of the UK's Eight Great Technologies - and bridging these areas of UK research expertise will likely catalyse significant downstream wealth creation by aiding in developing new technologies with a wide array of future applications. Furthermore, it will lead the way in combining these key areas so that the use of synthetic biology methods in the production of biomaterials and composites becomes a realistic prospect in the UK, and one that will likely attract significant investment as well as widespread research and media interest.

The applied research of this project, the biosynthesis of advanced materials, will open up a new avenue of applications in synthetic biology in UK and Europe, not just for the defence sector but well beyond. It will provide tools to improve existing industries and may yield an entirely new industry sector of its own, which will likely have a downstream impact on many consumer goods as well as aiding advances and improvements in medical healthcare, transport and even space exploration. Bacterial cellulose is already demonstrated as a useful material for electronics, displays, wound dressing, audio equipment and more. The possibility of affordable precise biosynthesis of bacterial cellulose composites will likely impact on all these industries and yield applications in as yet unanticipated industries as well.

The foundational work proposed will have broad impact in the rapidly-growing industrial synthetic biology sector as it demonstrates how a toolkit for precision engineering of an industrially-relevant organism can be achieved. 'Domestication' of industrially-attractive microbes is a key challenge for expanding synthetic biology's reach into industrial biotechnology and the workflow we have taken to do this for Acetobacter will likely provide a template for repeating this with other organisms. The foundational work on methods to develop composites and aerogels from bacterial cellulose will also aid in development of bacterial cellulose-based applications in industry and we anticipate that valuable IP could be generated in this area.

We anticipate that the planned products of the project; layered composites and advanced aerogels will have immediate impact in the defence sector where they will provide improved impact protection with lower weight and cost than existing materials and we plan to work closely with DSTL to ensure this. We hope that these materials are one day saving lives in real-world scenarios. Modifications to these same materials could also see their use elsewhere, and working with textiles researchers and artists/designers will give us an opportunity to explore these possibilities further.

Finally, this project will also impact educational training, teaching new skills to those employed on the project and also providing opportunities to extend the research into undergraduate teaching via research competitions such as iGEM. The UK has had remarkable success in teaching synthetic biology, producing many world-class undergraduate projects, so investment in further research here in the UK is critical to retaining the best students in the country and building a successful UK-based synthetic biology industry.

The attached Pathways to Impact document further details how we anticipate working with companies and promoting our work to the general public, and how we will exploit knowledge generated in the project and promote future research collaborations.