Decarbonization & microalgae

CarbonWorks

Decarbonization & microalgae

One day - soon? - our planet will be a carbon-free world.

Without fossil carbon, of course - we need carbon, we're made of carbon ourselves!

And without fossil carbon, how will our societies organize themselves?

From the point of view of energy production, we should find solutions with renewable energies and decarbonized energies.

But when it comes to producing the inputs we need for our food, our agriculture, the chemicals we need and the raw materials we use in industry, where are we going to find the carbon that makes them up, which today comes from fossil or mineral resources?

It won't be possible to find it in nature - at least not in the quantities we need. Nature is in fact under increasing pressure: droughts, floods, falling agricultural yields, competition between economic players for access to biomass.

So we have to look elsewhere for carbon.

That elsewhere is CO₂.

At CarbonWorks, the living inspires our work, and even inhabits it.

To get the carbon C out of the CO₂, CarbonWorks uses a service that nature does us very well: photosynthesis. Photosynthesis is the ability of most plants to capture the carbon C they need from CO₂, while releasing a molecule of oxygen O₂ into the atmosphere.

And for this CarbonWorks uses microorganisms that do it with immense talent:

photosynthetic microalgae.

These microalgae are fascinating microorganisms. They are organisms ranging in size from 1 to 100 microns, which capture CO₂ through photosynthesis, and also know how to produce particular molecules: limestone, silica, lipids, proteins, toxins and so on. By choosing the right strain of algae, we cultivate micro-factories that naturally produce the desired molecule, and thus the renewable resources we're looking for.

The difficulty, today, is that we don't know how to cultivate microalgae on the scale needed in terms of renewable resources as well as CO₂ capture.

This is precisely CarbonWorks' challenge. CarbonWorks is developing an innovative technology for growing microalgae on a large scale: while conventional crops produce 80 to 100 tonnes of biomass/ha/year, CarbonWorks is aiming to produce 5,000 tonnes of biomass/ha/year and, to achieve this, capture 10,000 tonnes of CO₂/ha/year.

This is known as Carbon Capture and Utilization, or CCU.

Microalgae can do a lot of things. When we talk about production on the scale needed, we're talking about large volumes. And for CarbonWorks, the 1st application for microalgae in large volumes is human food.

CarbonWorks is developing applications for its partners in agriculture (biocontrol products as a contribution to the Ecophyto II plan) or biostimulant products to offset falling agricultural yields, nutraceuticals (omega 3, for example, to provide health solutions without resorting to overfishing), animal feed and proteins. But it's also about cosmetics, pharmaceuticals and biosourced chemistry!

In a world without fossil carbon, in a world in which nature is under pressure, allying ourselves with the living to produce our resources of tomorrow is essential and keeps the whole CarbonWorks team busy.

Learn more about the CarbonWorks approach

The invention of photosynthesis on planet Earth

In his book La vie sociale des Plantes (Fayard), Jean-Marie Pelt describes the emergence of photosynthesis on Earth in an evocative, poetic yet totally scientific way.

"It was then that Life achieved its second stroke of genius: the invention of photosynthesis, i.e. a now inexhaustible and inexhaustible source of glucose [whose origin is the carbon contained in CO₂], from which all living processes could indefinitely feed. Photosynthesis was Life's answer to the greatest challenge it had ever faced: starvation. From now on, [Life] would have its syntheses carried out by living beings themselves, more precisely by those among them who had acquired the ability to make chlorophyll.

If the limestone fossils of Bulawayo in Rhodesia [now Zimbabwe] are to be believed, the first trace of a chlorophyllous being dates back 3,100,000,000 years. Life then dragged on for almost another billion years before communities of blue-green algae, the first chlorophyllous beings, developed strongly, this time leaving abundant traces in the fossil record.

Chlorophyll, the green pigment of plants, is one of the essential molecules of life; a sort of solar cell, it captures the energy of light rays and uses it to synthesize - from the simplest and most abundant molecules: water and the omnipresent carbon dioxide - the sugars that are the essential materials of life: this is photosynthesis. Chlorophyllous organisms, whether microscopic algae or green plants, are therefore factories that produce living matter; this is the primary role of a meadow or forest. And like all factories, they produce waste, in this case the emission of a "polluting" gas: oxygen.

Reinventing photosynthesis.

Starvation! "Photosynthesis is Life's answer to the greatest challenge it has ever faced: famine. A shortage of glucose over 3 billion years ago, making it necessary to find energy in light and carbon in the ultra-present CO₂ in the atmosphere. Today, there's a shortage of carbon, since for reasons of human survival, we want to avoid going underground to find the carbon we need; and, in the same dynamic, it's in CO₂, via photosynthesis, that we're going to find some of the answers.

Photosynthesis is indeed part of the answer to a world without fossil carbon. We can't do without carbon; where are we going to look for it? In CO₂!

That's what we've been doing for over 10,000 years via agriculture or in the exploitation of woodlands: it's photosynthesis that we're exploiting.

But today, this natural exploitation of photosynthesis is no longer sufficient. Our needs have grown, while the biomass in which we live (nature) is undergoing unprecedented attrition. Droughts, or simply heatwaves, floods, fires, deforestation, declining agricultural yields, increased competition for access to biomass for industry, all contribute to reducing its availability.

All these factors are prompting us to invent a new way of producing additional biomass through photosynthesis!

That's the challenge CarbonWorks is taking up: CarbonWorks has invented a process for growing photosynthetic microalgae on a large scale. With the aim of capturing CO₂ through photosynthesis, on the one hand, and producing additional biomass, on the other, with such high surface yields that this production does not compete with agriculture.

Why microalgae??

Microalgae are the microorganisms that invented photosynthesis.

Thanks to an anteriority of over 1 billion years, thanks to the fact that they are unicellular organisms, microalgae have a growth and multiplication capacity unique among photosynthetic organisms. And therefore a capacity to produce biomass - and therefore capture CO₂ - far superior to terrestrial plants. For the fastest of them, these microalgae split every 2 to 7 hours in suitable conditions*, and every 24 hours or so for commonly produced strains.

What's more, these same microalgae have developed strategies for adapting to their environment. To do so, they have learned to produce certain molecules, such as carotenoid pigments that protect the cell from excess light and its deleterious effects on the photosynthetic apparatus, saccharide polymers that form a gangue around the cells and enable them to attach themselves to supports or protect themselves from an unfavorable environment, and temperature-resistant proteins that enable them to live in volcanic environments. Microalgae have also developed the ability to move in an aqueous environment thanks to the flagellum, and to build a protective wall around the cell, which can be of various types, such as silica in diatoms or limestone in coccolithophores.

Using these strategies, for example, microalgae produce 7 to 31 times more lipids than plants under conventional culture conditions.

*: Yu, J., Liberton, M., Cliften, P. et al. Synechococcus elongatus UTEX 2973, a fast growing cyanobacterial chassis for biosynthesis using light and CO2. Sci Rep 5, 8132 (2015)

Within ecosystems, the role of microalgae is above all to build up a gigantic quantity of biomass from atmospheric CO₂ and available mineral elements, while producing oxygen. This biomass is the first link in the food chain, particularly in the ocean, which is commonly referred to as phytoplankton.

Microalgae are the primary source of essential nutrients such as long-chain polyunsaturated fatty acids (EPA and DHA), essential for the development of many animals (including fish and humans), and carotenoid pigments, powerful antioxidants that protect cells from free radicals and UV radiation. Astaxanthin, a red carotenoid pigment synthesized by certain microalgae, is responsible for the pink or red color of shellfish, salmon flesh and flamingo feathers.

Microalgae have been used in the economy since the 1950s.

The cultivation systems used are extensive, essentially raceways, tubular systems and flat panels. These are tried and tested systems, which are well suited to the objective of limited production. They take up a lot of land, producing no more than 80 to 100 tonnes of biomass per hectare per year. They are therefore used for low-volume applications, mainly cosmetics and certain nutraceutical applications.

And tomorrow?

Tomorrow, i.e. soon, CarbonWorks will be offering the use of its new-generation photobioreactor, an industrial photobioreactor with a surface yield of 5,000 t biomass/ha/year - and therefore 10,000 t CO2 captured/ha/year.

It is this performance that will unlock the use of microalgae in industry, in order to decarbonize it. Thanks to this capacity to produce large volumes of microalgae, industry has the means to decarbonize its inputs, by manufacturing them from its own CO2 emissions.

This is CCU: Carbon Capture and Utilization. By extracting the carbon we all need from CO₂ rather than from underground, CCU avoids the emissions usually associated with the production of industrial raw materials.