Heightened concerns over global warming and fossil fuel supply, security, and prices necessitate the implementation of alternative, sustainable routes to the production of chemicals and fuels. Whilst much attention has focussed on cellulosic processes, particularly through microbial-based processes, this is proving challenging, as are catalytic routes to biofuels from whole biomass. An alternative strategy is to directly capture carbon before incorporation into lignocellulosic biomass. Acetogenic bacteria species, such as Acetobacterium woodii are able to capture carbon (in the form of CO2) through anaerobic gas fermentation and reuse that carbon in products that displace their fossil-derived counterparts.
Acetogenic fermentation represents a versatile industrial platform for the sustainable production of commodity chemicals and fuels from diverse gas resources derived from industrial processes, coal, biomass and municipal solid waste (MSW). We will devise a new sustainable route to the important platform chemical 3-hydroxypropanoic acid (3-HP) using an Acetobacterium woodii chassis. 3-HP is ranked 3rd by the US Department of Energy (DOE) in the list of twelve platform chemicals which can be derived from biomass. 3-HP can serve as a starting point for production of acrylic acid (representing a $ 10 billion market together with the respective esters), acrylamide, malonic acid, poly(hydroxypropionate), 1,3-propanediol, and propiolactone. There is no commercially viable route to 3-HP from fossil feedstocks. From renewable raw materials, BASF, Cargill, and Novozymes recently demonstrated the production of 3-HP. However, identified bioroutes to 3-HP all rely on glycerol, fatty- acids, or sugar as feedstocks, which are vulnerable to price volatility and impact food and land availability. In contrast, the use of waste gases will supply an abundant and cheap non-commodity, non-food carbon source, thus dramatically lowering production costs, while concomitantly contributing to climate protection by consuming greenhouse gas emissions.
The overall goal of the CO2CHEM consortium is to derive a new manufacturing route to the important platform chemical 3-hydroxypropionic acid. Our innovative approach will be based on an acetogenic bacterial chassis, Acetobacterium woodii, and the use of waste CO2 gas, in combination with H2, as the feedstock. The assembled academia-industrial consortium provides the multidisciplinary skills and expertise needed to deliver this goal.
The specific objectives of CO2CHEM are:
1. Design, testing and implementation of the requisite genetic tools to bring about the necessary modifications to the process organism, A. woodii.
2. Identification and quantification of enzymes required for 3-HP biosynthesis
3. Sourcing and assembly of the requisite encoding genes and their optimised expression in A. woodii.
4. In-silico modelling in combination with ‘omic’ analysis to guide process improvements through the rational inactivation of competing pathways
5. Directed evolution of prototype process organisms with improved tolerance to 3-HP
6. Laboratory and industrial scale fermentation optimisation to develop a robust gas fermentation technology on CO2 +H2 mixtures
7. Implementation of techno-economic feasibility studies (TEA), life cycle assessments (LCA), and overall systems simulations analysis.
These specific objectives will be met through the implementation of multi-disciplinary, interrelated workpackages, comprising pivotal component sub-tasks, each led an appropriate member of the CO2CHEM team.