GASCHEM: Optimising industrial gas fermentation for commercial low-carbon fuel & chemical production through systems and synthetic biology approaches

Global Energy demand is expected to increase by up to 40% by 2030. The key challenge facing the global community is to not only increase the sources of energy supply, but to also maximize the use of sustainable forms of energy to safeguard the environment while ensuring that the latter do not detrimentally impact food supplies. In this regard, renewable sources of energy will play an increasing role in the global primary energy supply. The UK government, along with the majority of the civilised world, have now set challenging targets for reductions in greenhouse gas (GHG). Centre stage is the need for the sustainable production of hydrocarbons for energy, lubricants, and high value chemicals.

Traditional routes to chemical generation through biological systems have been reliant on the conversion of the more tractable components of plant biomass (sugars and starch) into chemicals, and in particular biofuels. The microbes employed ferment the easily accessible sugar and/or starch of plants, such as sugar cane or corn, and convert them into biofuels, most commonly ethanol. This has led to concerns over competition with use of these products as food, and a re-focussing of efforts on so-called 'second generation' biofuels. These are generated from cell wall material (lignocellulose) derived from non-food crops or agricultural wastes, such as willow and straw, respectively. Cell wall material is a product of photosynthesis, whereby plants convert atmospheric carbon dioxide gas (CO2) into sugars which are then used to assemble the complex carbon-based polymer, lignocellulose. For the fermentative growth of microbes on plant cell walls, lignocellulose must first be converted back into simple sugars. However, lignocellulose is extremely resistant to breakdown. Overcoming this recalcitrance in a cost effective manner is proving extremely challenging.

An alternative route would be to directly capture carbon, by harnessing the ability of certain bacteria, typified by Clostridium ljungdahli, to 'eat' the gas carbon monoxide (CO). When CO is injected into the liquid medium of fermentation vessels it is consumed by Clostridium ljungdahlii and converted into ethanol. Fortunately, CO is an abundant resource, and a waste product of industries such as steel manufacturing, oil refining and chemical production. Moreover, it can be readily generated in the form of Synthesis Gas ('Syngas'), by the gasification (heating) of forestry and agricultural residues, municipal waste and coal. By allowing the use of all these available low cost, non-food resources, such a process both overcomes the "Food versus Fuel" issues associated with traditional ethanol production, and circumvents many of the challenges associated with 'second generation' biofuels. Furthermore, capturing the large volume of CO (destined to become CO2 once released into the atmosphere) emitted by industry for fuel and chemical production provides a net reduction in fossil carbon emissions.

The Industrial Partner in this project, LanzaTech, have developed a versatile and robust process based on such a 'gas-eating' bacterium, and demonstrated its ability to produce chemicals from the off-gas of a Steel plant. Current products include ethanol, and another alcohol (butanediol) which, unlike ethanol, has potential as a valuable chemical, solvent or polymer. The University of Nottingham has developed world-leading genetic tools which can be used to both enhance the productivity of the current process, and extend the number of products the organism can make. Working together, the Nottingham tools will be used to improve our understanding of how LanzaTech's 'gas-eating' bugs convert carbon monoxide into chemicals. Thereafter, this knowledge will be exploited to both increase the yields of existing products, and extend the range of useful chemicals that can be made.

Gas fermentation allows low carbon fuels and chemicals to be produced in any industrialized geography without consuming valuable food or land resources. Working with LanzaTech we will use metabolic engineering to both better understand and thence optimise and extend product streams through systems and synthetic biology approaches.

WP1: A Systems Approach to Understanding Alcohol Production (Yr 1-3)
We will: (a) establish and validate procedures for the analysis of the transcriptome, metabolome and key enzyme activities of cell culture samples; (b) investigate the relationships between gene transcription and metabolic products through a series of perturbations studies, in which samples are taken as process conditions are varied from steady state EtOH and 2,3BD production, and; (c) establish a predictive model of EtOH/2,3BD production from gas fermentation and then undertake an iterative process of hypothesis and testing through mutant creation to progressively refine the model.

WP2: Maximising Levels of EtOH and 2,3BD Through Metabolic Engineering (Yr 2-4)
Using knowledge gained, and models generated, in WP1, we will: (a) undertake modeller-led genetic modifications of metabolic pathways to maximise either EtOH or 2,3BD production, and; (b) test and optimise product yields in laboratory-scale gas fermentation (LanzaTech)

WP3: Synthetic Biology Routes to Novel Product Streams (Yr 3-5)
We will: (a) synthesize and assemble component operon parts for production of chemical targets in C. ljungdahlii; (b) optimise the system through iterative hypothesis and testing, and; (c) evaluate and optimise chemical product yields at laboratory scale

WP4: Industrial Biotechnology (Yr 4-5)
Strains will be evaluated by: (a) transfering the most promising clones to LanzaTech for lab scale testing and product extraction; (b) conducting trials of the most promising clones at the LanzaTech Pilot Plant, and; (c) if appropriate, testing at Demonstration scale in Shanghai

WHO WILL BENEFIT?

The overall aim of this project is to enhance and extend the capabilities of acetogenic bacteria in terms of fuel and chemical production from sustainable resources. As this is an Industrial Partnership, the primary beneficiary other than the University of Nottingham is LanzaTech. They will directly commercialise all useful strains that emerge from the project and will have first refusal on any foreground intellectual property that arises.

Both parties have extensive global networks of commercial contacts and strategic partners. For example, LanzaTech have partnerships in numerous industry sectors including steel making, oil refining and chemical production (see the LanzaTech web site: http://www.lanzatech.co.nz/content/partnerships) including a Joint venture with Baosteel, the world's second largest steel maker. Nottingham have partnerships/ collaborations with EBI, Qteros, Lanxess and Genencor (N America), Evonik, Universities of Munich, Ulm and Berlin (Germany), TMO Renewables Ltd, Invista, Unilever and Green Biologics Ltd (UK), Metabolic Explorer Ltd, INRA and CNRS (France), the Chinese Academy of Sciences and the Mumbai Institute of Chemical Technology (India). Working together, LanzaTech and UoN will seek to maximise these links for the benefit of both organisations.

The successful commercialization outputs will have a rapid and global impact for both humanity and the environment. It will reduce greenhouse gas emissions and environmental pollution, provide an alternative to the use of food or farm resources for the production of low carbon fuels and chemicals. It is therefore of benefit to society, ultimately impacting on health and well-being.

HOW WILL THEY BENEFIT?

Project outcomes will allow improved fermentation process economics, encouraging more rapid and wide spread adoption of gas fermentation to produce low cost, low carbon fuels and chemicals. The partnership are anticipated to directly benefit from the outputs of the project through their commercial adoption. Additionally, the partnership intends to explore strategic licensing deals with third party organisations. These will take the form of up front and milestone payments as well as ongoing royalty streams. The successful scale-up and commercialization of processes will assist the UK, and other national governments in meeting challenging 'greenhouse' gas reduction targets, and contribute indirectly to food security. The generation of chemicals and fuels from waste gases will additionally impact on reducing reliance on fossil reserves, and therefore increase national fuel security.

The use of low carbon fuels to displace petrol reduces localized pollution from transport thus improving public health and in turn national productivity, ie, EtOH petrol blends reduce smog formation. The American Lung Association credits ethanol-blended petrol with reducing smog-forming emissions by 25% since 1990, toxic exhaust emissions by as much as 30%, toxic content by 13% (mass) and 21% (potency), and tailpipe fine particulate matter emissions by 50%.

Our programme is tailored to allow definitive benefits to be realized within the project's timeframe. Thus, the initial target is to improve the productivity of the existing LanzaTech EtOH process, due to begin commercial operation in 2013. Our work should benefit commercial EtOH production by 2014/15. Commercial production of 2,3 Butanediol should be achieved in an equivalent timescale. The production of our other targets will be realized during the latter stages of the project, and be in the demonstration phase by 2017.

The project will provide the opportunity for staff working directly on the project, together with affiliated postgraduate students, to become trained in the strategically important areas of 'Systems' and 'Synthetic' Biology, 'Industrial Biotechnology and Bioenergy'. These skills will be translatable to many areas outside of acetogens, enhancing future job prospects.