A photosynthetic biomanufacturing platform for the development of circular economy and a more sustainable industry

The Problem

of global unsustainability

The way we produce things is not sustainable. Our whole economy is structured in a linear fashion: extract, refine, consume, and throw it away. This is causing huge amounts of polluting waste, paving the road for resource scarcity in the near future.

  • Carbon dioxide levels are higher than they've been at any point in the last 3.6 million years

    CBS News, April 2021
  • Climate crisis likely creating extreme winter weather events, says report

    The guardian, Sept. 2021
  • Climate crisis has shifted the Earth’s axis, study shows. Massive melting of glaciers has tilted the planet’s rotation, showing the impact of human activities.

    The guardian, Apr. 2021
  • Scientists are seeing an 'acceleration of pandemics': They are looking at climate change

    USA Today, Sept 2021
  • Climate crisis is 'single biggest health threat facing humanity,' WHO says, calling on world leaders to act

    CNN, 11 October 2021
  • Carbon dioxide levels are higher than they've been at any point in the last 3.6 million years

    CBS News, April 2021

Are you aware of these problems?

At 4c_Fuels we are!

Challenges of our times

The threat of Climate Change...

Accumulation of greenhouse gases due to human activities is causing global issues that affect every living being on this planet. We cannot continue like this, and we all know it. Every chemical element has its cycle on Earth, and Carbon is not an exception. For millions of years carbon has been buried deep down in the Earth’s crust, quietly and peacefully. But since the industrial revolution we have been extracting and burning that dormant carbon reservoir, taking its energy and generating CO2 gas in the process. We have shifted the weighting scale: carbon is now above us in the air instead of down below buried in the Earth. And this is happening so quickly in the geological time scale that we are changing the environmental conditions of our whole planet, think about how big that is.

Pollution image
Renewable technologies are not for everyone...

We knew about climate change and the end of oil for a long time ago. That is why we have been trying to find alternative sources of energy that do not continue emitting CO2, the so-called ‘renewable energies’. However, these new technologies are yet emerging and have some limitations regarding their availability and how these power can be stored and accessed by the final consumers. To name a few, ships or planes cannot be powered with renewable technology due to their high energy consumption and limitations of storage in batteries. They still require the use of fuels and have been excluded from the sustainable revolution we are living in nowadays.

Sustainability is not just clean energy...

Renewable energies provide us with just that: clean energy. What about the materials we need to produce physical things? Plastics, textiles, drugs, pigments, cosmetics, fertilizers: they cannot be produced from just energy. We need feedstocks to convert them into products. Nowadays there are no established technologies that could provide us with the feedstocks we need in a sustainable way. Some alternatives are arising to either utilize waste as a feedstock or to generate new sustainable materials. However, they struggle to compete with well-established non-renewable sources.

The problem with biobased renewables

You might have heard about bioproducts, like biofuels or biomaterials. These technologies allow us to convert biomass into goods that replace traditional fossil-based products. However not all of them are actually sustainable. Despite these products coming from renewable feedstock, the whole industrial process might not be sustainable in the end.

For example, the biofuels industry has travelled across some generations. First attempts used vast extensions of arable land, directly competing for space with food supplies. Further approaches relied on agricultural waste or non-alimentary crops. However these biofuels required more energy to be produced than the energy they could provide. In other cases, like palm-oil biodiesel, the process is energetically viable but not sustainable regarding their global impact.


Cyanobacteria: A sustainable production platform

The Power of The sun

When thinking about renewable sources of energy, the sun looks like a promising candidate. Every year the sun irradiates earth's surface with 7,000 times more energy than our current global demand. Not surprisingly, the sun is the main energy source for life, and nature excels in sustainability: everything is used and nothing is wasted.

Nature's Toolbox

During millions of years of evolution organisms have fine-tuned a whole set of tools capable of converting almost anything into useful products to fulfill their needs. This makes nature the perfect place to look for inspiration and strategies to achieve sustainability,

Inspired by the wisdom of nature, we asked ourselves...

Could we use sunlight to drive the production of chemicals, fuels and materials, employing nature's toolbox?

The era of phototrophs synthetic biology

Since ancient times, we have been exploiting nature’s toolbox to obtain products like cheese, beer or antibiotics. However, our ability to harness nature’s potential to transform matter into valuable products was limited to the native abilities that organisms have already developed to survive. Nowadays, the emerging field of synthetic biology allows us to engineer organisms to solve new problems that nature has never encountered before.

Thanks to synthetic biology, we are able to engineer a biological production platform that converts sunlight into valuable products. For this purpose, we looked around for what nature had already designed: phototrophs.

Phototrophs are organisms that use sunlight as energy. Most of them use this energy to fix atmospheric CO2 and convert it into more complex molecules.

Among all of these organisms, cyanobacteria are the most efficient ones in harvesting sunlight for carbon fixation. In contrast with microalgae or plants, cyanobacteria are prokaryotic organisms, which make them easier to engineer

Taking all of this together, we are committed to expand cyanobacteria’s native abilities by applying synthetic biology to produce valuable chemical products out of sun and carbon dioxide.

Developing a circular bioeconomy

Our goal is to develop a truly sustainable photosynthesis-driven production technology which will use sunlight as energy source and carbon dioxide and water as feedstocks. Our platform overcomes the limitations of conventional heterotrophic bioprocesses, which require a continuous input of supplies that are used as both carbon and energy sources. With our platform all of the produced materials are synthetized out of the most relevant atmospheric pollutant : Carbon Dioxide.

We aim to establish an integrated circular process. By the end of the product’s life cycle, the generated waste can be reused as feedstock and upgraded to a valuable product again. Powered by sunlight this cycle can provide us with valuable products with zero net emissions in a sustainable fashion.

Our technology is based on engineered cyanobacteria, capable of capturing CO2 and converting it into useful chemical products. As a proof of concept we will engineer an n-butanol production process.

The development of this novel manufacturing technology is the aim of the 4C_Fuels project. 4C is the acronym for Cyanobacterial Cyclic Carbon Capture, which summarizes the philosophy behind our ideas.

Despite focusing our project in n-butanol production, we aim to settle the foundations for a truly sustainable solar-driven chemical manufacturing platform.

cyanobacteria image

4C_Fuels. New Solutions

But wait, if all of this sounds so great why haven’t we seen a change in the way we produce things?

Actually it’s happening! It’s called Green Biorefinery, and it aims to obtain products using engineered photosynthetic organisms in a sustainable way.

However, it faces some challenges that 4C_Fuels aims to address:

Challenge #1

The Products

Most of the products we need, such as fuels or plastics, are not naturally produced by photosynthetic organisms. Thus, current industrial practices need to transform natural feedstocks into useful products. These conversions require high amounts of energy and resources, leading to unsustainable production processes.

Solution #1

Metabolic Engineering

Thanks to the increasing knowledge on Synthetic Biology we can now engineer new microorganisms capable of directly producing the products we need. Although this approach is not new, it has not been widely explored for photosynthetic organisms until now

✔️ Our goal is to engineer a cyanobacteria capable to directly produce a useful product: butanol.

❔ But, once you got there, how are you going to obtain the final product?

Challenge #2

Product recovery: Downstream Processes

One of the main bottlenecks for the development of Green Biorefinery is the high costs associated with product recovery. Current processes rely on harvesting biomass and extracting the products of interest out of it. Depending on the industry this step can account for up to 85% of total production cost. The current paradigm is focused on biomass as a resource to exploit.

Solution #2


We aim to simplify the downstream processes by engineering our microorganisms to directly produce and secrete the product of interest. This eliminates the need of harvesting and further processing of biomass. Our cells will feed on CO2 and sunlight and convert them into butanol, like a living catalyst. This circumstance can improve the viability of industrial processes, as we have studied within our implementation & proof of concept sections

✔️ We see biomass as a tool for conversion, not as a resource to harvest and exploit.

❔ That sounds amazing! But could this technology be scaled up to the industrial level?

Challenge #3

Need for improved industrial chassis

Most of the photosynthetic microorganisms used at the industrial scale have several drawbacks inherent to their nature, slowing down the consolidation and establishment of phototrophic-based industry. Photosynthetic microorganisms usually suffer from lack of robustness and slow growth rates, limiting their suitability as industrial chassis.

Solution #3

Novel robust fast-growing strains

For our project we will use a new cyanobacterial strain: Synechococcus elongatus PCC11801.. As well as other recently discovered fast growing strains, PCC11801 has a set of features that make it ideal for Industrial applications: the ability to grow in a wide range of conditions and high tolerance to harsh environments typically found in industry (robustness), a fast-growing phenotype and similarities with well-studied laboratoratory strains

✔️ Our goal is to establish PCC11801 as an ideal industrial workhorse.

❔ Ok, but doesn’t it have other limitations?

Challenge #4

Large-Scale Cultivation of photosynthetic microorganisms

There are some problems all phototrophic-based industries have to deal with, which are not related with the specific strains they use. Photosynthetic microorganisms precise huge reactor setups since they usually grow at very diluted concentrations. In addition, these cultures are exposed to fungal contaminations, grazing by other wild living entities, and the risk of release when working with genetically modified organisms.

Solution #4

Cyanobacterial Encapsulation

To solve all of these issues we propose CELL ENCAPSULATION. Via physicochemical treatment of the cells we generate biohybrid materials where the cells reside secure from environmental threats like pathogens or grazers. Encapsulated cells require smaller reactors as higher biomass concentrations can be achieved and metabolic performance is enhanced since cell division is limited. Likewise, encapsulation serves as a biocontainment method to prevent release risks

✔️ Via cell encapsulation we aim to develop a true photobiocatalyst suitable for industrial needs.

Taking together these key aspects, our project aims to solve the main problems of the current photosynthetic-based industry, developing a photobiocatalytic manufacturing platform. Starting with n-butanol production as a proof of concept.

Dive deeper within 4C_Fuels project