ENGICOIN · Engineered microbial factories for CO2 exploitation in an integrated waste treatment platform

The ENGICOIN proposal aims at the development, from TRL3 to TRL5, of three new microbial factories (MFs), integrated in an organic waste anaerobic digestion (AD) platform, based on engineered strains exploiting CO2 sources and renewable solar radiation or H2 for the production of value-added chemicals, namely: MF.1) the cyanobacteria Synechocystis to produce lactic acid from either biogas combustion flue gases (CO2 concentration ~ 15%) or pure and costless CO2 streams from biogas-to-biomethane purification.MF.2) the aerobic and toxic metal tolerant Ralstonia eutropha to produce PHA bioplastics from biogas combustion flue gases and complementary carbon sources derived from the AD digestate.MF.3) the anaerobic Acetobacterium woodii to produce acetone from the CO2 stream from biogas-to-biomethane purification.High process integration will be guaranteed by taking advantage of low-grade heat sources (e.g. from cogenerative biogas-fired engine or an tailored PEM electrolyser), exploitable side gas streams (e.g. O2 from electrolysis, CO2 from biomethane purification), low-price electricity produced during night-time by a biogas-fired-engine cogeneration unit or even intensified operation conditions (e.g. up to 10 bars pressure for the anaerobic acetone production bioreactor; led-integrated photo-bioreactor). This is an essential feature, alongside with the high conversion rates enabled by synthetic and systems biology on the above microorganisms, to achieve competitive selling prices for the key target products (1.45 €/kg for lactic acid; 3.5 €/kg for PHA; 1 €/kg for acetone).Notwithstading the key application platform (anaerobic biorefinery based on organic wastes) the innovative production processes developed have a great exploitation potential in other application contexts: flue gases from different combustion appliances (e.g. cement kilns), alcoholic fermentation CO2 streams (e.g. lignocelluosic biorefineries, breweries), etc.