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BIOtechnological processes based on microbial platforms for the CONversion of CO2 from ironsteel industry into commodities for chemicals and plastics

Periodic Reporting for period 3 - BIOCONCO2 (BIOtechnological processes based on microbial platforms for the CONversion of CO2 from ironsteel industry into commodities for chemicals and plastics)

Reporting period: 2021-01-01 to 2022-06-30

The EU chemical industry relies heavily on non-renewable fossil resources as raw materials, power and fuel, being one of the main industrial sectors contributing to CO2 emissions and worldwide it currently generates about 6.7% of the total CO2 emissions. The dependence of the chemical industry on fossil resources must be reduced and it is necessary to develop environmentally friendly, sustainable and economically feasible processes to produce chemicals. Moreover, the emissions of greenhouse gases (GHG) must be reduced to have a reasonable chance of limiting global warming. Bio-CCU is an emerging technology with few applications, except in pilot and demonstration projects. The largest barrier to wider deployment is the high costs. BIOCON-CO2 fully addresses the following expected impacts of BIOTEC-05-2017 by applying a strategy to biologically transform CO2 emitted by the iron&steel industry. The strategy, based on a three decision-making stages, has enable the development and optimization of four MCF and thus contributing to overcome the current challenges to generate key chemical products (C3-C6 alcohols, PHB, formic acid and lactic acid) and to provide chemical, plastics and feed industry with an alternative and sustainable feedstock. BIOCON-CO2 will promote the EU leadership in utilization of MCFs and enhance the European competitiveness in Circular Economy approaches.
Cutting-edge technologies and strategies have been developed for each stage of the BIOCON-CO2 platform that can be combined as “puzzle pieces” depending on the target chemical and the used biological system.
• Creation of a database of gas composition. The CO2-producing industrial partners (iron&steel, cement and electric power industries) have analysed and integrated statistics of gaseous effluents from different gas streams. This database has guided the research performed on WP3 to WP5 to develop robust MCFs able to use real gases with any or minimum pre-treatments as raw materials.
• CO2 solubilisation technologies. An array of technologies/strategies for increasing CO2 solubility, applicable to the different types of microorganisms and enzymes have been developed. This includes: a fixed trickle bed reactor with advanced materials, gas fermentation systems such as AnaRAMOS and glasshaker, pressure fermentation and an engineered carbonic anhydrase enzyme with improved performances.
• Bioprocess development. During BIOCON-CO2 four microbial cell factories (MCFs) had been developed using anaerobic microorganisms (Clostridium spp. for C3-C6 alcohols), aerobic microorganisms (Cupriavidus necator for PHAs) and enzymes (formate dehydrogenase for formic acid and multienzymatic system for lactic acid production), thus proving high flexibility and versatility to the BIOCON-CO2 platform. In each MCF different strategies to increase tolerance to impurities and to enhance their productivity applying genetic improvement tools have been investigated.
• Downstream processes: The main goal of the BIOCON-CO2 approach for the downstream processes is to create an integrated process for extracting and purifying the different building blocks based on their differential properties of the products compared to those of the media they are in. An automated tailored statistical tool, called DS-OptiDoE (DSODE), able to optimise downstream strategies has been developed and it has been published as an open-source tool in the platform Zenodo (DOI: 10.5281/zenodo.6606670). Efficient downstream processes for C3-C6 alcohols through pervaporation, PHB by cell lysis and precipitation/washing, lactic acid using a membrane filtration cascade of ultrafiltration, nanofiltration and reverse osmosis, and formic acid through two successive steps of nanofiltration and reactive liquid-liquid extraction have been developed. In addition, an integrated biocatalytic-chemocatalytic route to convert n-butanol into 2-ethylhexanol and an enzymatic process for ring-opening polymerisation of lactic acid to PLA have been developed.
• Demonstration in industrially relevant conditions: The goal is to demonstrate and validate the developed biological processes in a real industrial environment and with actual flue gasses from the steel mill industry. a mobile gas fermentation pilot plant, Bio Base Mobile Pilot Plant (BBMPP) has been constructed and installed at Arcelor Mittal site. The BBMPP was designed as flexible in operation as possible, though allowing the ability to work with a wide array of microbial strains all requiring process-specific operational procedures. The BBMPP is equipped with 3 bioreactors pressurizable up to 8 barg: a 157L stirred tank reactor or STR, a 24 L STR, and a 10 L trickle-bed reactor or TBR. Even some additional experiments should be performed for optimizing the process, the results obtained in the fermentation of C. necator to produce PHA using real gases are very promising.
Taking into account that CO2 emissions of EU iron&steel and cement&lime industries account for 19.2% and 10.5% of the industrial emissions in 2010 (concentrated at specific sites), these sectors have a great potential to reuse CO2 and to reduce the environmental and economic (carbon tax) associated burden. The use of CO2 to produce chemicals will reduce CO2 release both by consuming it and by decreasing the use (and dependence) of fossil resources for chemicals synthesis. BIOCON-CO2 is expecting to capture 4% of the market volume of these chemicals at medium term (5 years after the industrial implementation) and 10% of the market share at long term (10 years), i.e. 2 around 1.4Mtonne CO2/year and 3.5Mtonne CO2/year (respectively) would be consumed (3% and 48% of global and European iron&steel industry CO2 emissions, respectively).
Although the current knowledge generated and the low maturity of Bio-CCU technologies do not allow to revise the initial objectives, the outcomes of BIOCON-CO2 let us be optimistic about the potential of Bio-CCU strategies and their contribution to reduce CO2 emissions in medium to long term.
Development of tools: i) genetically improved Clostridia strains for alcohol production; ii) improved Carbonic Anhydrase (CA) to enhance CO2 solubilization; iii) gas fermentation systems for real-time online monitoring of CO2 transfer rate for optimizing culture media and process conditions; iv) electrofermentation as strategy to reduce process energy consumption by means of increasing productivities and avoiding H2 injection; v) more robust and efficient formate dehydrogenase and alcohol and lactate dehydrogenase and pyruvate decarboxylase for formic and lactic acids production; vi) immobilisation of whole-cell biocatalyst for formic acid production; vii) a decision making tool for optimum downstream processing; viii) efficient downstream processes based on pervaporation, cell lysis and precipitation/washing, membrane filtration (ultrafiltration, nanofiltration and reverse osmosis) and reactive liquid-liquid extraction have been developed.
Development of infrastructure: i) a pressurized bioreactor operating in industrially relevant conditions at lab utilizing real gas effluents, and ii) a mobile pilot and demonstration bioreactor.
These tools could be transferred to other bioproducts produced from CO2, which is the main contribution of BIOCON-CO2 to the European CCU strategy.