EPO-Acetogen

Climate change demands that mankind abandons the use of fossil energy sources. Many times, industrial biotechnology has been proposed as a sustainable alternative in this context. To implement industrial biobased production of chemicals and fuels suitable feedstocks and microbial catalysts are needed. A circular carbon economy based on the abundantly available CO2 (from industrial sources or captured directly from air) and renewably generated energy (e. g. wind or solar) could be established where C1 compounds such as CO2 (+H2), carbon monoxide (CO), formate or methanol serve as sustainable feedstocks for bioproduction of every day needed products such as fuels and bioplastics. Acetogenic bacteria are prime candidates in this context, as this group of anaerobic bacteria can utilize all these feedstocks with high energetic efficiency. However, this efficiency comes at the cost of low availability of ATP, the cellular energy currency, a fact that has been described as "life at the thermodynamic limit". This leads to low growth yields and a narrow spectrum of possible products. Next to carbon, nitrogen, oxygen and hydrogen, phosphorus is one of the key elements of life and metabolism. Phosphorus naturally exists in different oxidation states. One reduced phosphorus compound is phosphite which is naturally found in small quantities on Earth today but is also used industrially as a fertilizer as well as in the automotive and chemical industry. In the context of cellular energy metabolism phosphite is interesting because there are certain anaerobic bacteria which can utilize phosphite as an energy source and can generate substantially higher levels of cellular energy (ATP) compared to acetogens. The main objective of EPO-Acetogen is to develop the model acetogen Acetobacterium woodii into an organism with the ability to use phosphite as an energy source. The main rationale is that by implementing phosphite utilization, acetogen metabolism can be doped, i.e. ATP production can be increased beyond levels that are naturally possible. To achieve this goal, a broad approach including microbiology, genetic engineering, fermentation, analysis of microorganisms with a toolbox of bioanalytical methods and computer-generated models will be used. Ultimately, it is anticipated that EPO-Acetogen will provide a powerful chassis to conduct both fundamental studies relating to the role of microbial Pt oxidation in the geochemical phosphorus cycle as well as applied studies relating to systems metabolic engineering of acetogens for C1+H2+Pt- to-chemicals/fuels bioproduction.