The scope of this project is to design and study predefined syngas-converting microbial co-cultures, supplemented with electricity for zero-CO2 emission syngas fermentation (SGF). Syngas is a gaseous mixture of CO, H2 and CO2, which can be generated during the gasification of carbonaceous materials (including biomass and wastes). SGF has received increased attention as a route to produce liquid fuels (e.g. ethanol, full-scale stage) or biochemicals (development stage). However, during CO fermentation about two-thirds of the carbon is emitted as CO2. The complete fixation of CO2 into products is possible, but requires extra reducing power, e.g. by supplementing H2 or electricity. Building on research conducted at MIB (syngas conversion to medium-chain fatty acids (MCFA)) and ETE (bioelectrical conversion of CO2 to MCFA) we will study the integration of syngas fermentation and microbial electrosynthesis (MES).
Firstly, we will isolate and characterize novel strains using as source a highly enriched MES culture available at ETE that converts CO2 to MCFA. We anticipate to isolate strains efficient in taking up electrons from a cathode or in mediating those to other microbes. In parallel, a co-culture of C. autoethanogenum and C. kluyveri, previously shown to convert syngas to MCFA, will be used as initial model for studying integrated SGF + MES for improved CO2 fixation. Further on, we will establish novel co-cultures with the new isolates and study cathode-microbe and microbe-microbe interactions. With this, we expect to obtain novel co-cultures that can efficiently convert syngas to MCFA, while capturing CO2.