Presenting BioSFerA at the Biomass Day 2023

Today, the Biomass Day 2023 event is taking place in Athens. The Greek conference is dedicated to the bioenergy role in the energy crisis and gathers public authorities and main scientific community representatives to deal with this topic.

Considering the Russia-Ukraine war and global geopolitical conflicts, it is always increasingly difficult to operate bearing in mind the decarbonization and climate neutrality European goals, as set by the Green New Deal and the Fitfor55 plan. The conference guides the discussion on the active role of the bioenergy in our economy to answer some questions: how can the contribution of bioenergy in the expansion and diversification of EU energy sources be easily and consistently ensured through the “RePowerEU” project? Is there a possibility in Greece and the EU of a more substantial energy use of biomass to alleviate the unsustainable energy costs of industries, commercial companies /services and households?

BioSFerA partecipates at the debate having our coordinator Konstantinos Atsonios (CERTH) as representative and handling a presentation on “Gasification technologies for the production of liquid and gaseous biofuels and their contribution to sustainable transport”.

For the full presentation (in greek) CLICK HERE.

 

Biomass Conversion and Biorefinery Journal: a new paper on BioSFerA

The CERTH team published a new scientific paper resulting from the development of the BioSFerA’s concept. The publication, entitled “Design considerations of an integrated thermochemical/biochemical route for aviation and maritime biofuel production“, describes the conceptual design of the novel integrated thermochemical-biochemical BtL process performed in our project.

The process design has been analysed considering three different operational scenarios examined and assessed mainly through overall performance indicators: carbon utilization (CU), energetic fuel efficiency (EFE), liquid fuel mass yield, and overall energetic/exergetic efficiency. As outlined in the study, design considerations and their impact on process efficiency were performed within the assumed scenarios, including parameters such as internal/external hydrogen securement via pressure swing adsorption (PSA)/water electrolysis and oxy-/air-acetate fermentation as well as autothermal/allothermal operation of the catalytic reformer. Aim of the study is also the definition of the key process specifications and the evaluation of the proposed concept compared to other competitive technologies.

To have a full overview of the BioSFerA process design, explore the entire article, free available in the Biomass Conversion and Biorefinery Journal (Springer) and in our Publications section.

DOI: https://doi.org/10.1007/s13399-023-03754-4

Updates from BioSFerA H2020: biological process status and forward project’s steps

Another important General Assembly meeting was held last October within the BioSFerA Consortium.  On this occasion, the partners met in Ghent (Belgium), at the Bio Base Europe Pilot Plant’s headquarter: last project updates and an interesting tour at the biobased process plant made well successful the meeting at BBEPP.

At this stage of the project, the biological process plays a significant role for all the following steps. Several partners contribute to the lab-scale optimisation to fully comply the further piloting activity and the overall BioSFerA concept achievement. Starting from the microorganisms’ investigation, CSIC updates the Consortium with its work to improve both acetogenic bacteria and oleaginous yeast strains on their production rates and contaminants resistance through a metabolic engineering strategy. On one hand, the Spanish research centre is working to optimize the overproduction of enzymes in the acetogenic bacteria Moorella, by increasing the copy number of the genes introduced in the strains using plasmids. Furthermore, they have genetically modified the oleaginous yeast to create an obese strain overexpressing synthetic DGA genes (diacylglyceride acyltransferase) and deleting a gene involved in the fatty acids degradation metabolism. This Y. lipolytica yeast strain has been tested in different media with single or combined substrates (glucose-acetate-glycerol). The results showed better performances in all the cases for the GMO yeast strain than the wild type. Next months, CSIC plans to test new obese strains and perform other experiments to increase the production of TAGs with higher C14 content.

First lab-scale results begin to be achieved in the gas&liquid fermentation processes, where BBEPP and CARTIF are mainly involved. They are currently testing the Moorella strains considering different gas composition and other process parameters to understand the biomass behaviour and its productivity. From the BBEPP side, the syngas fermentation trials are currently under operation using 1 L batch fermentation and 10 L continuous bioreactors aiming to increase the process performance; meanwhile, CARTIF is conducting the gas fermentation tests on 1 L pressurized bioreactor, discovering the glucose as possible co-substrate useful to increase biomass and acetate production.

For what concern the liquid fermentation, BBEPP successfully cultivated Y. lipolytica on the gas fermentation effluent in shake flasks, thus confirming the BioSFerA concept. Furthermore, a series of bioreactor trials were performed to assess the TAG accumulation potential of the Y. lipolytica strain modified by CSIC on acetic acid (AA) and glucose. In parallel, CARTIF also completed fed-batch and continuous optimization trials testing different substrates, such as AA substrate, AA and glycerol or only glucose. The parameters still need to be optimised to reach the final target set at 60 % TAGs accumulation and 50-100 g/L TAGs. CARTIF will continue the trials focusing on the AA/glycerol substrate and improving concentrations and other process parameters.

Last stage of the biological process is the recovery and purification of the TAGs, which is currently under investigation by BBEPP. During the meeting, a sample of purified microbial oil produced by Y. lipolytica was showed to the Consortium to better understand each step development. A sample of the obtained oil will be also sent to KPRT for further analysis, while a broth sample will be available for ENVIPARK to perform the steam explosion and advances with the downstream process step.

 

Progress from the piloting: last September BBEPP and VTT met to define next steps and integration process between the two gasification&fermentation units. A HAZOP study was conducted, risks were listed, together with mitigation measures, as well as the following BBMPP’s shipping and the preliminary operational conditions. BBEPP is also taking care of the fermentation scaling-up activities, running trials on 150 L fermenter with Y. lipolytica and glucose as substrate to set up the process parameters. The gas&fermentation piloting phase will start in April 2023 and will be finished latest by October 2023.

 

Continue the BioSFerA model concept development: the EMMS model for the DFB (Dual Fluidized Bed) and the full chain model at commercial scale are performed by CERTH with SFW and partners collaboration. The techno-economic analysis will consider the entire value-chain accounting for capital and operational costs and biofuel minimum selling price. A sensibility analysis will be performed from the base-case scenario in order to identify hotspots for cost optimization. At the end, at least 3 scenarios in different EU countries will be analysed to verify the versatility of the model at territorial level. The analysis will be completed with the LCC and LCA results.

A first market assessment was also present by GF, showing the competitor market analysis of different biofuel processes. Likewise, the evolution of pricing over the years, as well as forecasts for future pricing, were discussed for conventional and alternative technologies. According to GF some serious impacts could be originated by the Ukrainian war on biofuel production, due to European imbalance of energy supply and offer. From a legal point of view, KPRT rather reports possible further revision of a large number of European policies and directives associated with the Fit-for-55 package.

 

The Consortium is also very active from the dissemination side and the partners participated to several events during last months. Worth mentioning, in November ENVIPARK took part at the international fair on circular economy ECOMONDO (Italy) with an institutional stand and its projects, included BioSFerA. The project was even presented during a workshop organised by GLAMOUR, another European project with an active collaboration.

After more than two project’s years, BioSFerA has reached some relevant results and the project is well advancing. Some important challenges still need to be faced, but the activities respect the project schedule and the Consortium is hopeful to easily accomplish them, thanks to the high-level and cooperative partnership. Further updates will be released after the meeting planned next May 2023 at VTT’s premises in Finland.

The BioSFerA Consortium at BBEPP premises during the 5th GA meeting

The biological pathway for the fuels of the future

Interview with Jose M Sanz Martin, CARTIF

A central step to fully comply with the successful operation of the BioSFerA model is to ensure the highest yield of the fermentation steps by optimizing the different parameters that influence the biomass growth and its productivity.

In the project, CARTIF is one of the partners with an important role in the biological process for the lipids production at lab-scale. Thanks to its experience as Applied Research Centre Foundation in terms of R&D and technology transfer activities, CARTIF is leading the biological step referred to the project’s WP3 activity. Here, few questions to Jose M Sanz Martin, Researcher at CARTIF in the Agrifood and Sustainable Processes Division, to better understand the BioSFerA biological process development at lab-scale and the double-stages fermentation process that leads to the acetate before and after to the TAGs lipids production:

What are the last updates on the optimisation of the acetate fermentation process parameters for C14 and C16-18 TAGs production?

We are currently working on finding the best bioreactor strategy to favour lipid accumulation and for this we are testing nitrogen-limited conditions, continuous feeding of acetate as a main carbon source and recycling of cells using hollow fibre membranes. We are also using an engineered Yarrowia lipolytica strain developed by CSIC, which has improved triacylglycerides (TAGs) productivity. The results are promising and all this leads us to increase lipid production with respect to the wild-type strain.

 

Did you find any barriers and if yes, how are you trying to dealing with them?

Regarding the gas fermentation, one of the key aspects to improve the process is the choice of a suitable working strain, as well as the establishment of process conditions that allow for higher productivity. In addition, in order for the gases to be used efficiently by the microorganisms, it is very important that they are solubilised properly in the culture medium. To solve these problems, we have selected a strain of the acetogenic bacterium Moorella thermoacetica that is capable of producing a large amount of acetate from syngas, and we have improved the growth conditions by using bioreactors that allow us to control the flow rate of the gas fed as well as to increase the working pressure to favour its solubility in the medium.

As for acetate fermentation with Y. lipolytica, although acetate is a promising cost-effective and suitable carbon source for microbial fermentation, its use as the sole carbon source to enhance lipid synthesis is not very favourable from a metabolic point of view. To overcome this problem, we have confirmed that feeding a co-substrate such as glycerol can help to improve biomass production and drive metabolic flux towards TAGs production.

1.5 L continuous fermentations for TAGs production (installation of cell recycling system and continuous feeding strategy). Detail of the growth of Y. lipolytica from acetate+glycerol.

 

What are the last promising results?

In relation to acetate fermentation with Y. lipolytica, although we have not yet achieved the expected objectives of lipid production, we observed that the addition of glycerol during the fermentation process together with a nitrogen starvation strategy and limited stress conditions greatly favours the accumulation of TAGs by facilitating their metabolic biosynthesis. From here, we are conducting tests to find the most suitable concentration of glycerol to maximise this lipid accumulation.

 

For the overall biological production process of lipids from syngas at lab scale, several partners are involved in its optimisation and in different way. As leader of this activity, how this collaboration can impact the research and results?

I believe that the collaboration between all the partners involved in this work package is very beneficial for the progress of the project, as we can share the large amount of work that needs to be done according to the experience and capabilities of each partner. For example, VTT’s expertise in gasification has allowed us to select the best process conditions to achieve a syngas suitable for fermentation with microorganisms.  CSIC has obtained genetically modified strains of Moorella and Yarrowia that will maximise the productivity of the process, which is essential for the next stage of scaling up. In terms of bioprocess optimisation, BBEPP has focused more on optimising the anaerobic fermentation conditions, while CARTIF has focused on aerobic fermentation. Finally, ENVIPARK has contributed its expertise in the further processing of the lipids obtained in the fermentation broth.

In addition, the sharing of all the work done and the close collaboration that we have maintained throughout the project has allowed us to clarify many doubts and resolve the technical difficulties that we have encountered. It is certainly very gratifying to be able to work on this topic with some of the best researchers in Europe.

CSIC poster on the microbial lipids research in BioSFerA

Last 2-4 November, CSIC participated at the 6th Congress of Applied Synthetic Biology in Europe.

An important opportunity to show the last results about BioSFerA through the presentation of a poster entitled “Lipase overexpression in Yarrowia lipolytica for direct biofuel production“. It describes the research work led by our partner CSIC in the framework of the project: final goal is to build a Y. lipolytica obese strain expressing a robust lipase for the in situ production of biodiesel. The engineered strain will be able to produce TAGs from glycerol and to produce a lipase (either intracellularly or surface displayed), which after cell lysis with organic solvent and methanol will perform the direct transesterification of TAGs into FAMEs (biodiesel).

Download the poster here.

BioSFerA at the ECOMONDO Exhibition

From 8th to 11th November, BioSFerA will take part at the ECOMONDO Exhibition, International fair dedicated to the circular economy and the ecological transition with base in Rimini (Italy).

An important annual event for circular economy experts from several sectors to meet each other and receive updates about the last technological innovations. BioSFerA will be there in different ways:

  • virtual stand, from our partner’stand Environment Park, search for BioSFerA in its projects’ list;
  • in-presence with some project’s representatives from Environment Park, scheduling B2B meetings from the virtual stand with each person;
  • project presentation at the INDUSTRIAL&REPLICATION WORKSHOP, 9th November, 2-6 pm, organised by GLAMOUR project. The event aims to give last updates on the clean technologies for second generation biofuels, gathering experts and International research projects. Here the link to register at this hybrid event and the agenda.

 

For more information, please contact marianna.franchino@envipark.com

 

BioSFerA at the 2022 International Freiberg Conference on Waste Gasification

Our partner VTT participated at the 2022 International Freiberg Conference on Waste Gasification, held in Germany last 19-21 September.

Ville Nikkanen presented its research on syngas processing in a poster titled “Fluidized bed gasification of wastes and syngas processing”.  The work shows the technical results of the gasification process exploration from different types of feedstock, selected for BioSFerA and using a Dual Fluidised Bed Gasifier.  Main steps and related parameters for the gasification process optimisation have been identified, together with the final syngas quality analysis and possible future applications. After the lab test, the VTT’s syngas production pilot will be integrated with the BBEPP’s mobile gas fermentation unit to produce acetate by microbial activity and contribute to the advancing of the BioSFerA concept’s scaling-up.

 

Discover the VTT’S POSTER.

BioSFerA H2020, project’s update and meeting in Madrid

For the first time, after two years of project, the BioSFerA Consortium meets in person in Madrid. The first physical meeting took place last 3rd – 4th May at the Center for Biological Research Margarita Salas (CIB) of our partner CSIC, the Spanish National Research Council. The two-days meeting was also the opportunity to visit the CIB-CSIC’s laboratories, where a large number of researchers conduct their researchs on biotechnology, included the experiments for BioSFerA.

 

Concerning the CSIC’s activities, the research centre is continuing its trials currently dedicated to the genetic modification of selected acetogenic bacterial and oleaginous yeast strains: based on genetic engineering strategies, CSIC has created 8 recombinant Moorella strains with different acetate production rates. Results are still not fully satisfying, so that CSIC will move forward to better understand the recombinant bacterial behaviour, considering extreme fermentation conditions and syngas contaminants. On the other hand, genetic modifications on several genes involved in lipid metabolism are also in progress for Y. lipolytica, the oleaginous yeast used in the triacylglycerides (TAGs) production phase from acetate.

 

Meanwhile, the investigation of the gas & liquid fermentation processes for the parameters’ optimization are still ongoing. The activities were conducted on pressurized bioreactors of 1 L and 10 L dimensions for CARTIF and BBEPP respectively and using realistic data on the VTT’s syngas mix. They operated in different conditions to explore the factors influencing the acetate production, such as the use of different media or the application of a continuous fermentation mode with a membrane for cell recycling. A general finding from these tests is that increased biomass concentration can lead to higher volumetric acid acetic production. In addition, increased pressure was applied to overcome gas transfer limitations. Further investigations on the oleaginous yeasts’ fermentation step are also proceeding: BBEPP presented the results so far of acetate fermentation trials in the 7 L fed-batch bioreactor applying a pH-static feeding strategy, whereby different trials were performed using the both wild-type and genetically modified Yarrowia strains. CARTIF achieved tests using a fed-batch fermenter and two different continuous feeding strategies (high constant and gradually increased flow rate), but both the feeding and the cell recycling strategies need to be optimised to further increase TAGs production. First experiments were also performed by ENVIPARK with its steam explosion pilot plant as first step in the downstream process for the TAGs recovery. These first trials were conducted using a broth sample provided by BBEPP and literature parameters for an initial setting.

 

Even the preparations for the pilot process activities are advancing: VTT updates the Consortium with the successful accomplishment of the Factory Acceptance Test and the last steps to conclude the gasification unit, while BBEPP informed about the finalisation of the Bio Base Mobile Pilot Plant (BBMPP) construction. A draft timeline of the work has been presented, defining the transportation of the BBEPP’s mobile unit to the VTT site at the end of the year 2022 and the launch of the pilot process integration within 2023.

 

Within the progresses of the project’s activities, it is time for the scaling-up of the BioSFerA’s concept, starting with the DFB (Dual Fluidized Bed) gasification system as first block to help its functionality and transferability at industrial level. The techno-economic, environmental and social analysis has started as well. RINA, and the other partners involved in the activity, are preparing the basis for the future assessments related to the LCA/LCC analysis (CERTH), and the social-LCA too (NTUA). One reason of discussion was the current energy crisis and the impact of the COVID-19 outbreak on the expected techno-economic performance indicators, which will need to take into account these aspects.

 

Finally, the dissemination activities continue to follow the project’s progresses and advance with new activities, such as the release of the official BioSFerA’s newsletter at the end of May and the update of the website with the news related to the pilot process. On the 4th May afternoon, after the meeting, a workshop on “Advanced Technologies for Green Molecules Production” was also organised in hybrid format in synergy with other two projects COS2MOS and Life Biomass C+, giving evidence of the first project’s results and its contribution to the biotechnology research development. After this fruitful meeting, the Consortium expects to meet again in October, this time in Belgium at the BBEPP’s headquarter.

The BioSFerA Consortium at CSIC premises during the 4th GA meeting

VTT EXPLAINS: THE SYNGAS PROCESS AND ITS INTEGRATION WITH THE FERMENTATION UNIT

Interview with Ville Nikkanen

The syngas production from different biomass feedstocks is the first process step characterising the concept proposed by BioSFerA. Thanks to the exploration of these biofeedstocks from all over Europe, the improvement of the gasification process allows to increase the value of the BioSFerA’s technology according to sustainability and circularity principles. As initial stage, it is also crucial to have a good operative and performance control for the following gas fermentation steps and downstream process to achieve the final biofuels as expected.

VTT, as an expert in the gasification process, has carried out the bench-scale test at TRL4 with 5 different feedstocks, necessary to proceed with the second step of fermentation. These preliminary analyses are also important for the scale-up activity consisting into the integration of the BBEPP’s mobile gas fermentation unit with the syngas process and having as main results the construction and run of a pilot process plant at TRL5.

Mr. Ville Nikkanen, which has coordinated the VTT activity on the syngas production, explains more in detail the path taken and the future development concerning the syngas plant.

 

What tests have you conducted so far and what results have they produced?

Preliminary tests at bench-scale have been conducted to provide data describing the syngas composition produced by the feedstock used for the biological research and the following double-stage fermentation. The bench-scale tests were conducted in a bubbling fluidized bed gasifier (BFB), showed in figure 1, with continuous flows of feedstock, bed material (sand and dolomite) and gasification agents (H2O and O2). A hot gas filter and reformer units were used for eliminating particles and tars from the produced syngas. For removing trace impurities and for improving the syngas quality, a water scrubber and adsorber beds after the reformer unit were tested. The gas quality were analysed by using different online and offline gas analysis methods. During the experiments, the main parameters influencing the final syngas composition are the feedstocks and the feed gasses (O2, CO2, H2O, N2) and the used processing units. The achieved results show the reforming unit is required in the gas fermentation process in order to remove the harmful components (e.g., naphthalene and benzene). Moreover, gasses that are fed into the gasifier and reformer (O2, N2, H2O, CO2) and their volume flow influence the syngas composition more than the selected feedstock. Finally, water samples collected after the reformer unit seem to be suitable for gas fermentation. The long-term accumulation of impurities and the effect of this will be studied later in the project in piloting runs expected to be carried out in 2023.

 

How does the different feedstock affect the functioning of the system?

5 different feedstocks in the form of pellets have been tested: forest residue, bark, straw, sunflower husk and olive pruning. Higher concentrations of H2S, COS, HCN, and NH3 are measured with feedstock that have high sulfur (S) and nitrogen (N) content, such as straw, sunflower husk, and olive prunings. This might lead to larger requirements for the gas cleaning in the downstream, if these gaseous components inhibit the growth of microbes. Also, ash sintering can cause more operational problems in the gasifier if straw, sunflower husk, or olive prunings are used as a feedstock in the pilot process. Based on those bench-scale gasification tests all of the feedstocks could be potentially selected for the piloting runs, specifically because the reformer helps to average the syngas composition. Then the main criteria for the feedstock selection are their availability, cost, and sustainability.

 

What is the added value in integrating the syngas unit with the fermentation unit? What kind of technical limits must be overcome?

The integration between the syngas and fermentation units allows to join the best characteristics of each technology in the right combination in a single process. The thermochemical and biochemical approaches offset each other in some steps, reducing costs and enhancing the efficiency of the overall process. For example, the costs of sulfur (H2S) and nitrogen (NH3) removal could be potentially minimized as the microbes seem to be very tolerant toward these components. However, some specific components such as hydrogen cyanide (HCN, COS) can be potentially very inhibiting and toxic even at very low concentrations leading to a need to remove these components selectively. Sure, it is also a challenge to find the right syngas composition to feed the microorganisms, the conditions to exploit the technology according to the available feedstock, and from a bench to a pilot-scale until TRL5. One of the main technical parameters is the monitoring and minimisation of the inhibiting components in short and long-term operation activity. An ultra-cleaned syngas unit helps to control these data and a continuous syngas flow is required to minimise the production of unwanted substances from not standard operation.

 

What are the next steps and expected results to reach?

Last improvements to optimise the syngas production are focused on the minimisation of the operational risks in the piloting phase. Therefore, the main activity is the identification of the most critical impurities and, specifically, the impurity tolerance to better control the risks and select the only the necessary process units, reducing costs and enhancing the overall efficiency. In parallel, an action plan has been settled with BBEPP, in charge of the mobile gas fermentation unit. The main next steps and the shipping of the components at Bioruukki in Finland have been defined, planning to start with the integration operations in March 2023 to have the process completed by the end of March 2024. The pilot-scale gasifier can be fed with maximum 100 kg of biomass per hour. The aim of these piloting tests is to produce a realistic gas mixture for the gas fermentation and run the process continuously for hundreds of hours to verify the performance in a realistic environment and to scale up the gas fermentation step in an integrated process. Until now, we have worked together with BBEPP to identify some starting parameters to join the two units, such as the minimum gas pressure at the compressor inlet and also safety and automation requirements.

Figure 1 – Syngas process scheme: dual fluidized bed gasifier,
hot-gas filter and catalytic reformer unit.

 

Report Deliverable 3.1 – Bench-scale gasification tests at TRL4

Scientific Paper Activated Carbons for Syngas Desulfurization: Evaluating Approaches for Enhancing Low-Temperature H2S Oxidation Rate

The importance of the microorganisms’ study in the BioSFerA concept

Interview with José Luis García

Spanish Nation Research Council (CSIC), as one of the largest European public research institution with high expertise in the biotechnology field, gives its contribution to BioSFerA on biological processes at laboratory scale thorough its institute, the Center for Biological Research Margarita Salas (CIB) (Madrid). Its main activity is the research of the best microorganisms, playing a key role in the double stage fermentation characterising the BioSFerA process.

Exploring the micro level and the microorganisms’ interaction with the surrounding environment is crucial when moving processes from the laboratory to pilot scale level. Few questions to go deepen the CSIC activity and the biological research in laboratory with José Luis García, Research Professor at CIB (CSIC) and leader of the Environmental Biotechnology group:

 

As project partner, how CSIC contribute to the project and what is the innovative aspect led by your research activity?

Our main contribution to BioSFerA is to develop a new collection of system metabolic engineering tools that can allow to modify the acetogenic bacteria and the oleaginous yeasts in order to obtain robust bacteria and yeast that could render higher production yields of acetate and lipids than the natural wild type strains. Using these tools and considering the lessons learned during the implementation of the processes at industrial scale it will be possible to propose other modifications to improve even further the production yields.

 

Your work is focused on bacteria and their interaction with organic matter and the surrounding environment. What are the main limitations hindering bacterial activities to consider for their performance, specifically in the BioSFerA processes?

It’s important to consider the final objective of the process, which in BioSFerA is to transform the syngas obtained from biomass gasification into acetate that will be further used to produce lipids. Analysing our model, we can split it into two main steps: in the first one, we use acetogenic bacteria to transform syngas into acetate, whereas in the second step we use oleaginous yeasts to transform acetate into lipids. To develop an industrial efficient process the first problem that we have to handle is how to increase the bacterial production of acetate from syngas. This can be achieved by combining the production of enough microbial biomass from syngas and an efficient transformation of syngas into acetate. In addition, we have to take care of possible syngas contaminants that are toxic for the bacterial acetogenic strains and that can affect bacterial growth or viability. Hence, we have performed a screening of different acetogenic bacteria that are able to grow at high cell densities, that produce high amounts of acetate, and that are resistant or tolerant to some contaminant/impurities present in syngas.

Example of Y. lipolytica strains growing
on YPD (rich liquid medium) agar plates.

 

Considering the acetate production, how the syngas composition from the different biomass can affect the fermentation process?

As mentioned above, in BiosFerA we are traying to transform the residual biomass into syngas: a mixture of carbon dioxide, carbon monoxide and hydrogen, that is obtained by a process named gasification. The syngas, as result of a gasification process, depends on the origin and properties of the biomass which influence the presence of the contaminants and the syngas composition. Usually, the biomass gasification not only produces syngas, but also other compounds like hydrogen sulphide, hydrogen cyanide, benzene, ammonia, methane, etc. This means the production of acetate will be affected by the proportion of the main gases (CO2, CO, H2), that varies depending of the biomass and the gasification conditions and that are responsible of the bacterial growth and the acetate yields, and also by the presence of toxic unwanted contaminants. Therefore, it is important to find the most appropriated syngas composition as well as to eliminate as much as possible the unwanted contaminants to a level that can not affect bacterial growth or acetate production. 

 

What kind of approach have you followed in these research activities and how is the work coordinated with the other partners? What are the advantages of having such a broad, interdisciplinary team as BioSFerA?

In a very early steps, we have collected all the information available in the literature dealing with the metabolism, molecular biology and processes of the organisms of interest, this is acetogenic bacteria and oleaginous yeasts. Then, we have selected the best strains and performed a screening of their properties using different culture conditions in order to test which are the best acetate producers from syngas and lipid producer from acetate. After selecting the best performing microorganisms, i.e. the acetogenic bacteria Moorella thermoacetica and the oleaginous yeast Yarrowia lipolytica, we have used systems metabolic engineering approaches to identify the target genes that have to be deleted or overexpressed, to channelling the metabolism to the production of the metabolite of interest. After modifying the strains, they have been initially tested at CIB-CSIC at lab scale using shake flask cultures and then transferred to CARTIF and BBEPP for fermentations in bioreactors at high volume levels. At this point, the interdisciplinary nature of the different groups involved in BioSFerA project allows us to find the best operational conditions to produce the compounds of interest at pilot and industrial scales.

 

Acetate metabolism in acetogenic bacteria.
Target genes are indicated in colours.

Lipid (TAG) metabolism in oleaginous yeasts.
The main target genes are indicated in red.

 

So, first you analyse the organism’s metabolism to identify the best strains and then you guide them in the metabolic process of the desired substances, through genetic modifications. What is the value added to use GMO microorganisms?

GMO microorganisms are designed for different purposes, but in principle they are all aimed at increasing the performance of processes. The yield of the process can be increased by redirecting the carbon flux to the production of the desired product and at the same time by avoiding the formation of unwanted by-products. Additionally, as it is the case of lipids, we can also modify the microorganism eliminating the degradative pathways of lipids and fatty acids, facilitating that the decided final product is accumulated inside the cell, without the possibility of its further degradation. The GMOs constructed in BiosFerA project are oriented to increase the production of acetate from syngas in the case of acetogenic bacteria, and to increase the production of lipids from acetate in the case of oleaginous yeast. If required, the strains can be also modified to acquire other properties, for instance the resistance or tolerance to specific toxic contaminants.

Electroporator used to create OGMs

 

Detailed information on the biological research at laboratory scale carried out by the BioSFerA’s partners are available in the Deliverable 3.2Deliverable 3.3.

Further explore through the opinion-Editorial Letter by CSIC – Integrating greenhouse gas capture and C1 biotechnology: a key challenge for circular economy.

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