Anaerobic microorganisms: the invisible revolution for the industry of the future

by José María Sanz Martín | Apr 4, 2025 | CARTIF Blog, Environment

In a world seeking to reduce its carbon footprint and move towards a circular economy, anaerobic microorganisms are emerging as key players in the fight against climate change. These organisms, which thrive in environments without oxygen, have been used for decades in processes such as anaerobic digestion for waste treatment and biogas production. However, their potential goes far beyond this. Thanks to advances in biotechnology, anaerobic microorganisms are emerging as key tools for industrial decarbonisation through innovative processes such as gas fermentation, where they can transform CO₂ or CO into high value-added products.

Heavy industries, such as steel, concrete and petrochemicals, generate large amounts of CO₂ and CO as a by-product of their processes. Traditionally, these gases have been released into the atmosphere, contributing to global warming. However, synthetic biology and biotechnology have opened up a new avenue to harness these emissions and convert them into valuable products through the action of specialised anaerobic micro-organisms.

Anaerobic bacteria, such as Clostridium, Moorella and Acetobacterium, can use CO₂ and CO as a carbon source and transform them into organic compounds via specialised metabolic pathways. This process, known as gas fermentation, facilitates the conversion of industrial emissions into renewable chemicals, fuels and biomaterials, promoting a more sustainable economy. For example, Acetobacterium woodii and Moorella thermoacetica are acetogenic bacteria capable of converting CO2 in acetic acid, a key input for the chemical and food industry, while species as Clostridium Ijundahlii can produce acetate and ethanol, making them a viable alternative for the generation of biofuels and other products of industrial interest.

In addition to ethanol or acetic acid, anaerobic bacteria are capable of generating other compounds of interest such as butanol, acetone and other organic acids like formic, propionic or butyric acid. These products are key in the manufacture of plastics, solvents and other chemical compounds with high industrial demand.

Biopolymers and bioplastics represent another promising avenue. Cupriavidus necator can transform CO2 into bioplastic precursors such as polyhydroxyalkanoate (PHA) and polyhydroxybutyrate (PHB), biodegradable materials that provide a sustainable alternative to conventional petroleum-based plastics.

Finally, single-cell proteins obtained from CO2 can be produced by various species of hydrogenotrophs, which convert gases such as CO2 and hydrogen into protein-rich biomass. These microbial proteins can be used as an alternative source for animal and even human food, contributing to global food security and reducing pressure on traditional agricultural resources.

“These microbial proteins can be used as an alternative source for animal and even human food”

The use of anaerobic microorganisms for the conversion of CO2 into valuable products offers multiple advantages. In first place, it reduces industrial emissions, mitigating the environmental impact of highly polluting sectors. In addition, it allows a sustainable production of chemical compounds and fuels without relying on fossil resources or agricultural crops.

Industrial gas fermentation processes already exist today and are proving their viability. For example, the company LanzaTech has developed technologies based on acetogenic bacteria to transform CO2 and CO into ethanol and other chemicals, using waste gases from the steel industry. This technology has been implemented in countries such as China and Belgium, where operational industrial plants have successfully converted emissions into biofuels and renewable materials. Another case is Carbon Recycling International (CRI), which uses microorganisms in Iceland to convert CO2 into methanol, a key compound in the chemical and transport industry.

However, despite its enormous potential, the implementation of gas fermentation on an industrial scale faces technical and economic challenges. These include optimising bioprocesses to improve CO2 conversion efficiency, reducing operating costs and developing bioreactors suitable for large-scale production. In addition, it is necessary to advance in the design of genetically modified microorganisms that can maximise the conversion of CO2 into specific products of industrial interest.

The Biotechnology and Sustainable Chemistry area of CARTIF has developed during the last years an intense research activity around gas fermentation technology and the management of anaerobic microorganisms. Specifically, the execution of R&D projects such as BioSFerA or CO2SMOS has allowed us to position ourselves in the European panorama as an entity capable of working successfully with this peculiar class of microorganisms and to specifically optimise their growth conditions in pressurised bioreactor, in order to increase production yields of various compounds such as acetic acid, ethanol or 2,3-butanediol.

As research and development continues to advance, these microorganisms will play an even m

ore fundamental role in the transition towards a more sustainable industry and a society with less environmental impact.

Microorganisms and their importance in the soil: The secret of a sustainable agriculture

by José María Sanz Martín | Sep 29, 2023 | CARTIF Blog, Environment

When we think in agriculture, we often focus on the development of the plant, but we rarely consider the importance of proper management of the soil in which crops are grown. Soil is a vital resource that sustains our lives and provides the food that is indispensable for humanity, and its health is essential for sustainable agriculture and food security.

At first glance, soil may appear lifeless, but in reality, it is teeming with microscopic life. Healthy soils harbour a wide variety of microorganisms, including bacteria, fungi, protozoa, nematodes, etc. These organisms, which often go unnoticed, play an essential role in the functioning of terrestrial ecosystems.

Among the soil-dwelling microorganisms, many are beneficial to plant health soil quality in general. These microorganisms perform a number of vital functions:

1. Decomposition of organic matter: microorganisms break down organic matter in the soil, such as fallen leaves and plant debris. This action releases essential nutrients that can be absorbed by plants to support their growth.

2. Nitrogen fixation: nitrogen is one of the most important nutrients for plant growth. Some bacteria have the ability to fix atmospheric nitrogen in a form that plants can metabolise.

3. Protection against pests and diseases: some microorganisms act as biological control agents, helping to prevent plant diseases by competing with pathogens or producing antimicrobial compounds.

4. Improvement of soil structure: other microorganisms, such as bacteria or fungi, generate soil aggregates that improve soil structure, porosity and water holding capacity.

5. Nutrient cycling: they participate in the decomposition and release of essential nutrients, such as phosphorus, potassium and various micronutrients (zinc, iron, copper, calcium), which are essential for plant growth.

Unfortunately, modern agriculture has engaged in practices that often damage the diversity and population of beneficial microorganisms in the soil. Excessive use of chemical fertilisers and pesticides, intensive tillage and lack of crop rotation are practices that can damage or unbalance the microbial ecosystem present in the soil.

For example, chemical fertilisers may provide nutrients to plants, but they can also lead to soil acidifcation and negatively affect beneficial microorganisms. Similarly, pesticides intended to kill pests can negatively affect other microorganisms in the soil, which can trigger a cycle of dependence on agricultural chemicals.

Fortunately, there are agricultural practices that can promote soil health and the abundance of micro-organisms that play a positive role in plant development:

Organic farming

Organic farming avoids excessive use of chemical pesticides and fertilisers, which preserves the microbial ecology of the soil.

Crop rotation

Changing crops season after season encourages microbial diversity and avoids the build-up of specific pathogens.

Use of cover crops

Maintaining a vegetative cover on the soil throughout the year helps to maintain microbial activity and prevent erosion.

Composting

Adding organic compost to the soil enriches the microbial population and provides nutrients in a balanced way.

Reduced tillage

Minimising soil tillage reduces the disruption of microorganisms in their natural environment.

Use of green manures

Planting green manure crops such as legumes can increase nitrogen fixation and enrich the soil in nutrients.

Soil health is fundamental to agricultural sustainability and global food supply. Beneficial microorganisms, working in symbiosis with plants, play an essential role in preserving that health. As a society, we must recognise the importance of

these tiny creatures and adopt practices that promote their thirving in our soils.

At CARTIF, we have the experience gained through the implementation of several projects related to the proper management of microbiology applied to agriculture and especially to soils, either in the form of biofertiliser (SUSTRATEC proejct) or in the form of biopesticide (SUPERA project).

Maintaining soil health is not only essential to ensure abundant and nutritous harvests, but also to preserve biodiversity and mitigate climate change. By protecting and nurturing life in the soil, we are investing in a healthier and more sustainable future for our planet and future generations. Let us care for the land that cares for us.