SERDP funded research is making important advances in the application of synthetic biology tools to the production of energetic materials. Energetic materials, like propellants, explosives, and the constituents that make up these materials, are currently produced by chemical processes that often generate significant quantities of hazardous waste and subsequent environmental issues. Advances in synthetic biology offer the Department of Defense (DoD) opportunities to replace or significantly reduce problematic chemical processes. SERDP project WP-2333 is applying synthetic biology tools in creation of bacterial biocatalyst to produce a high purity biocellulose (BC) from glucose, which can subsequently be formulated into military grade nitrocellulose (NC), for use in propellants and other energetic materials.
NC provides the base material for many DoD propellant formulations. Current production uses feedstock cotton fibers and wood pulp that are prone to impurities, which decrease performance during storage and increase waste. Dr. Mark Fuller at CB&I and his team are working to develop a process that would replace the feedstock with a more refined BC, biosynthetically generated for production of NC.
The approach constructs a bacterial strain with a cellulose producing mechanism, controlled by synthetic biology. We have successfully knocked-out the native biocellulose synthesis ability of our bacterial strain,” explains Dr. Fuller who is now focused toward controlling the strains production of BC. His team has fully sequenced the genome of the bacteria, and produced a model of the metabolic pathways. These developments will increase the overall yield of BC produced by the strain, and will facilitate process scale-up. Using the generated BC, co-performers at the Naval Air Warfare Center – Weapons Division have synthesized small quantities of NC. This material will be characterized and tested to determine if it meets requirements for military use.
The development of environmentally benign bioprocesses for the production of energetic compounds and their precursors from renewable resources has the potential both to reduce the reliance upon foreign sources and promote manufacturing capability within the U.S. The development of biosynthetically generated, high purity BC will lead to the production of high performing NC that is more stable in storage, resulting in decreased waste. This process is also scalable, reproducible, and cost-effective. Given that the application of synthetic biology to the manufacture of energetic materials is somewhat new, this project will also serve to increase the knowledge base in this area, leading to additional opportunities in the future.