Biofissazione della CO2

Biofixation of CO₂: bio-oil and valuable products from microalgae

We use LED photobioreactors to cultivate microalgae to fix CO₂ and obtain bio-oils, nutraceuticals, pharmaceuticals and food bases.


We are working on innovative technology to fix CO2 through the cultivation of microalgae. At the Research Centre for Renewable Energy and the Environment in Novara, in collaboration with the Polytechnic of Turin and a network of Italian start-ups, we have started up a pilot plant with multilayer photobioreactors in which algae are fed by artificial light that uses wavelengths optimised for photosynthesis. The plant biomass produced, collected and dried is an algal flour that can be used in nutraceuticals, animal feed or cosmetics. The fatty fraction of the extract can be used to produce algal oil, which can then be used to produce advanced biofuels in Eni's biorefineries. Launched in November 2020, the new pilot plant in Novara has achieved very promising daily biomass productivity data that, projected on plants of industrial scale, could produce up to 500 tonnes of biomass and trap about 1,000 tonnes per year of CO₂ per hectare of land. Building on this experience, we plan to launch a pilot plant on an industrial scale, to be built within the Gela biorefinery.


Finding new ways to reuse carbon dioxide in industrial processes is part of the strategy to reduce the emissions of climate-changing gases. Such operations use the circular economy approach, which already features in our business model, to allow them to “close the anthropic carbon cycle”, Here, through the natural photosynthesis process, CO2 molecules are biofixed by microscopic algae, intensively cultivated in photobioreactors. This technology gives us both the possibility to reduce emissions in our business sectors, using them to cultivate algal crops, and to make use of areas which cannot be used for agricultural purposes, not to mention the opportunities for local development that launching business initiatives based on these plants could bring to the area.


Technological challenge

Like all plants, algae need the sun to grow. However, they are real living cells, in fact they reproduce by mitosis. It's possible to intensify and make their growth pattern more efficient, for example by using one or more specific light frequencies. In the pilot plant at the Novara Renewable Energy and Environment Research Centre we have created multilayer photobioreactors which feed the algae with light from an LED system, which guarantees uninterrupted 24-hour operation at any latitude.  The photobioreactors system consists of four innovative hydraulic panels in parallel, inside which the micro-algae circulate. Each of the panels is equipped with special LED lamps that diffuse light uniformly inside, using the wavelengths preferred by algae for photosynthesis. Light modulation by intensity and quality is controlled according to optimal growth conditions to intensify growth.

Eni has already previously researched CO2 biofixation with microalgae using sunlight, both in open pond (at the Eni Refinery in Gela) and in photobioreactors (at the Enimed site, in Ragusa). In the latter case, the research was based on technology from BioSyntex Srl (BSX), which involved the cultivation of microalgae fed by CO2 from activities managed by our subsidiary EniMed and concentrated sunlight with panels made up of thousands of Fresnel lenses that follow the sun and concentrate its rays in special optical fibres.

Industrial integration

The Novara pilot plant consists of four photobioreactors and is integrated with renewable energy sources. The technology on which it is based was developed by Photo B-Othic, with whom Eni signed a License Agreement. Photo B-Otic was created to support the development of bio fixing technology and starts from the initiative of MEG, Everbloom, Abel Nutraceuticals and the Cooperativa Arcobaleno, which is a majority shareholder and has promoted this entrepreneurial initiative, the result of ten years of research work in the field of nutraceutics and biotechnology in collaboration with the DIATI of the Politecnico di Torino. The potential transition to an industrial-scale pilot plant, which could be built at the Gela biorefinery, would allow us to further consolidate our expertise in algae biofixation and fully incorporate it into our industrial processes. The industrial development of biofixation technology is part of our strategy to decarbonise our assets. Being able to use the CO₂ from our activities and convert it into marketable products gives us the double advantage of reducing emissions and making new sustainable products available on the market. This initiative is currently at the advanced experimental stage required to optimise each step and maximise the efficiency of the entire process. Once we have built industrial scale production systems based on this technology, the areas of application could be diversified into agro-industrial, food and/or nutraceutical markets, and for our own business. Because of its particular design, the artificial light technology photobioreactor system has a reduced carbon footprint and is modular, meaning it can easily be installed in many types of industrial site, wherever there is carbon dioxide to be captured.

Environmental impact

The strengths of our microalgae decarbonisation technology are their low energy consumption, high efficiency, simplicity, modularity and compactness and, with the use of optimised wavelength LEDs, 24/7 uninterrupted operation. These factors make them suitable for applications in the most varied of contexts and compatible with the different operational scenarios that might be encountered in the energy industry. They generally adapt to all logistically favourable areas, from brownfield sites converted to sites that cannot be used for agriculture. Once they have been developed on an industrial level, these plants could make a significant contribution to reducing the CO₂ emissions generated by our upstream operations and other industrial sectors, with the added bonus of obtaining a finished product such as algal flour, which can be used in the downstream sector or sold for use in other production processes. Both of these factors mean that these technologies could be adopted on a broad scale, thus boosting the potential positive impact that it could have in terms of limiting carbon dioxide emissions.