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

Reporting period: 2019-07-01 to 2020-12-31

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.
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, will enable de development and optimization of four MCF and thus overcoming the current challenges to generate key chemical products (C3-C6 alcohols, Poly(3-HP), formic acid and lactic acid). The project will provide the chemical, plastics and feed industry with an alternative and sustainable feedstock, contributing to the EU leadership in utilization of MCFs and enhance the European competitiveness in Circular Economy approaches.
The work carried out during the first reporting period towards the achievement of each specific objective is given below:
• Creation of a database of gas composition
The CO2-producing industrial partners (Arcelormittal, Nesher and Laborelec Engie), have analysed and integrated statistics of gaseous effluents from different gas streams. This database has been shared with the rest of the project beneficiaries and is available within the consortium for modelling, lab-scale and pilot scale studies on relevant WPs (WP2-7).
• CO2 solubilisation technologies.
Flexible technologies and strategies for increasing CO2 solubility, applicable to the different types of microorganisms and enzymes have been developed.
AVT.BioVT has installed and is testing the safety system for pressurised fermentation processes to ensure safe operation with toxic and explosive gases such as CO2, CO and H2. AVT.BioVT has also developed pre-culture and monitoring device that will be used for characterizing the cultivation system where up to 4 gases in flexible compositions can be used as in-gas.
LEITAT is working in the design of the fixed bed trickle reactor in downward system, and the development of advanced packing materials that favour adhesion, growing and biofilm formation. Lastly, the increase in solubilization of CO2 using carbonic anhydrase has being investigated. In collaboration with RUG, a first round of 8 mutants has been selected for increase in stability.
• Bioprocess development.
The partners responsible for the development of the 4 microbial Cell Factories (Fraunhofer, LEITAT, UAB, Wageningen, RUG) have defined the gas requirements and potential boundaries for the bioconversion processes.
RUG has been working in the development of more robust LDH, ADH and PDC for the production of lactic acid. Regarding LDH, Amongst the screened mutants, one with an increased Tm (from 63ºC 71ºC) has been obtained.

The work carried out during the second reporting period towards the achievement of each specific objective is given below:
• 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: The development of 4 MCFs is ongoing. The MCF1 concerning the anaerobic production of C3-C6 alcohols has made significant progresses for hexanol and butanol production achieving titre of 0.57 g L-1 and 0.12 g L-1respectively. The cloning of missing genes of the CO2 fixation Wood-Ljungdahl pathway in the solventogen Clostridium beijerinckii NCIMB 8052 has been achieved. Co-cultures of acetogenic and solventogenic Clostridia has also been explored as a possibility to convert CO2 via acetate to C3-C6 alcohols through cross-feeding from acetogens to solventogens. The metabolic engineering of the MCF2 Cupriavidus necator is at the last step of the genomic integration of the malonyl-coA reductase gene in replacement of the phaA-phaB genes. In the meanwhile, optimisation of PHB production under autotrophic conditions has been performed. The MCF3 concerning the production of formic acid (MCF3) is under development. The production of formic acid with isolated enzymes was achieved with TsFDH and BmGDH. The MCF4 for the production of lactic acid is under optimisation studying the ratios of enzymes and possible immobilisation. So far, the maximum yield of MCF4 is of 8.5 µM.
• Downstream processes: A tool for optimal downstream processing has been developed. The development of efficient downstream processes of the target product is ongoing at the moment with synthetic effluents resembling the expected composition of real ones as well as validation of the target products have been carried out using commercial versions of them.
• Pilot plant construction: Significant progresses have been made regarding the design and the construction of the mobile gas fermentation pilot. The plan is to have the unit operational by the end of 2021.
Despite the delays experienced in the development of the MCFs, BIOCON-CO2 is expected to develop and validate at least two MCFs, according to the expected impact.
Potential Impact: 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 4 MCFs developed within the BIOCONCO2 for the production of CO2-based platform molecules will aid in the faster introduction of sustainable biotechnology-based CCU process into the industry and thus catalyze the reduction of CO2 emissions and boosting EU towards a circular economy. 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. 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).
The current progress of the tasks does not allow to revise the initial objectives. However, the analysis in the project of the adiabatic temperature rise during the gas fermentation suggests that it is not possible to achieve a high titer without cooling the fermentation reactor. A lot of heat is then generated at low temperature, and its recovery will increase the capital cost. Studies on how to valorise the heat produced are ongoing and will be considered within the project.
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