CO2 is a natural end product of metabolism in living organisms and significantly higher levels of the gas are exhaled than inhaled, for example. Plants in turn use CO2 during photosynthesis. As a natural nutrient and building block in the formation of biomass by plants and bacteria it is of particular interest in the field of biotechnology. There are even some microorganisms that feed exclusively on CO2 with the most famous examples found in proximity to hot springs such as those found in Iceland.
Yet the existence of these amazingly resilient organisms is no miracle; they are thought to date back to prehistoric times when concentrations of carbon dioxide in the earth’s atmosphere were much higher at around 20 per cent. This knowledge is the background of research aimed at the use of carbon dioxide in industry including the ZeroCarbFP research alliance coordinated by BRAIN. Just as sulphur dioxide advanced from being the culprit of acid rain to being a new valuable material in the form of calcium sulphate and plaster, the intention is to turn CO2 into a bioeconomy commodity. BLICKWINKEL talked to Dr. Jörg Mampel, research scientist and project manager at BRAIN, about his ZeroCarbFP project.
BRAIN: You are looking for microorganisms that feed on CO2 – which ones are at the top of your list?
Dr. Jörg Mampel: There are organisms known as chemolithoautotrophs, in short c-autotrophes, which obtain all of the carbon they need from CO2. Most of those bacteria live exclusively on CO2 and they use energy obtained from the oxidation of inorganic compounds such as methane, hydrogen, metal ions, nitrogen compounds and sulphur compounds for CO2 reduction. We identify and optimise these organisms for biotechnological applications to fix gaseous CO2 from secondary streams and waste streams and, subsequently, provide this as an efficient and advantageous material for industrial use.
BRAIN: What were the first steps in your research?
Dr. Jörg Mampel: The ZeroCarbFP Alliance started in 2013. During the first three-year research phase we were able to establish a two-stage process to recycle CO2 at laboratory scale. This was a huge success partly due to the fact that we do not need much room and we can get by with CO2 gas at relatively low temperatures – compared to alternative processes involving algae, for example. This facilitates extremely effective substrate provision and the microorganisms deliver correspondingly high CO2-fixation rates. First, however, we had to examine several thousand pre-selected microorganisms for special characteristics. Finally, we chose a few candidate-specialists which demonstrated particularly good growth characteristics and were able to produce substances that we may develop further to obtain platform chemicals.
BRAIN: Which materials are to be produced at the end of the process?
Dr. Jörg Mampel: The specific focus of our project is the provision of new and sustainable intermediate products for the manufacture of bioplastics. The bioplastics industry is still heavily dependent on fossil fuels. In our laboratory, we can already produce carbonic acids with carbon skeletons entirely made up of CO2. Every individual carbon atom in these skeletons originates from the added carbon dioxide. This places our research at the top of the field.
BRAIN: Which biogenic sources of CO2 do you want to use and at which scale?
Dr. Jörg Mampel: Within the framework of ZeroCarbFP we collaborate with the Südzucker company which produces bioethanol as well as sugar. During the fermentation process in bioethanol facilities, most of the CO2 contained in the plant material ends up in the fuel ethanol. Some of the gas is released, however, and it is this CO2 that we want to make use of. There are around 25 large bioethanol facilities in Europe alone, and about 200 in the USA. The amount of CO2 at our disposal amounts to millions of tonnes per facility and year.
BRAIN: Can the results of your research be applied to other sources of CO2 or are you mainly focussed on bioethanol facilities?
Dr. Jörg Mampel: We may indeed provide a portfolio of areas for use of CO2 to various industrial partners with different sources of CO2 and we may also still adapt the portfolio to various specialised areas of application. Essentially, our processes can be used for various point sources of CO2 which deliver high gas concentrations of biogenic, chemical or petrochemical origin. If necessary, we can also search our BioArchive or on-site facilities for further microbes using CO2. In the past, were able to show that bacteria living on CO2 had densely populated an industrial flue gas duct. We cultivated the respective bacteria in the laboratory, fed them on fumes and reached very promising results after their optimisation – just as we did with the bioethanol facilities project.
BRAIN: From the energetic point of view, CO2 is classified as ‘dead’. Huge amounts of energy are required to make use of the molecule. How can you achieve this efficiently?
Dr. Jörg Mampel: CO2 needs to be activated by energy before it can be used in biotechnology. We are currently using hydrogen to produce the required activation energy. However, we assume that industrial applications will involve renewable energy sources in the future. The shift towards biobased industry has to go hand in hand with an energy transition providing sustainable sources of energy. As part of the ZeroCarbFP Alliance, we are currently investigating alternatives such as the use of light energy or of surplus electricity to activate CO2.
BRAIN: What is the impact of CO2 recycling technologies on climate protection?
Dr. Jörg Mampel: We need to be realistic – the contribution of these technologies to climate protection will be limited in the forseeable future. Over 80 per cent of the petroleum extracted worldwide is used for energy, heat and transport, directly releasing CO2 into the atmosphere. The amount used in the production of valuable materials is still comparatively small. Our primary motivation at the moment is an economic one to give the user a competitive edge. The environmental advantages are an automatic added bonus.
BRAIN: Are there any further fields of application for biogenic CO2 you are looking at?
Dr. Jörg Mampel: We are already working on new fields of application on the basis of our two-stage technology platform and with the aim of recovering new resources. The processes and methods can be transferred, but we cannot reveal any details until we have done more research.
BRAIN: What will happen when bioplastics end up in landfill? Will the CO2 be released back into the atmosphere?
Dr. Jörg Mampel: This is, theoretically, possible and already under debate and investigation. We are building on scientific progress and new technologies-research in the field of bioeconomy is extremely dynamic. As Nature is our paradigm, all material should finally be fed back into the global material cycle, which largely runs on CO2. The big advantage of using CO2 as a building block for bioplastics is that fossil carbon is not required for the production process and does not have to be mobilized. The same applies to biofuels. An additional advantage of bioplastics is that the CO2 is bound for significantly longer periods and, hence, has no effect on the climate.
BRAIN: Which areas of research are you currently focusing on and what are the next steps?
Dr. Jörg Mampel: The current ZeroCarbFP development phase began in 2016 and our aim is to optimise our two-stage process in order to guarantee process stability and increase yields. We have already started upscaling to transfer the processes to a larger scale. Provided that the evaluation of the ZeroCarbFP development phase turns out well - and we are convinced it will - the pilot phase is due to start in 2019 and will last three years. Within this period we want to realise the upscaling to production scale. At present, we are considering a fermentation tank on the order of 200 litres. Later on, we will hopefully progress to a commercial application in order to provide new industrial materials.
Valuable resources derived from biogas waste streams
Within another research programme of the ZeroCarbFP Innovation Alliance, BRAIN is investigating the biotechnological processing of waste streams which are released during biogas production on the basis of rape seed oil. One focus is set on valuable resources used in the food and cosmetics industry.
Together with its partner, RWTH Aachen University, BRAIN worked on molecular issues in terms of optimisation of isolated microorganisms during the first research phase between 2013 and 2016. Since biogas producer Bioeton Deutschland GmbH constantly provided various batches of raw glycerine from the outset, they were able to investigate the effect of different purities on the production process.
The current 3-year development phase is focussed on the elaboration of certain procedures. Upstream processing (fermentation) and downstream processing (product separation of the fermentation brew as well as purification and concentration) are being developed bearing in mind the production scale. Priority is given to procedures that allow the production of natural products. A comprehensive analysis of sustainability and cost efficiency will also be performed. These projects are coordinated by research engineer Dipl.-Ing. Marc Gauert.