The need to reduce greenhouse gas emissions has intensified in recent years. This is highlighted by, for example, the European Union’s (EU) goal of reducing net greenhouse gas emissions compared to 1990 levels by at least 55% by 2030. Likewise, in the UK, the government is committed to reaching net zero greenhouse gas emissions by 2050.
Carbon capture and storage (CCS) is a fundamental element of the strategy behind these goals. The EU’s energy union has accepted the development of CCS as a “crucial priority”, and biotech is considered instrumental in achieving progress in this regard. In line with this, the UK government’s Net Zero Growth Plan discusses the need for biotech-derived energy and direct air carbon capture and storage plans.
In this article, we review the emerging biotech solutions and innovation occurring in the CCS field. We also discuss the opportunities for patent protection in this exciting area of research and development.
Nature’s carbon capture machines
Over millions of years, some of the most efficient carbon capture machines have evolved in nature. Algae, cyanobacteria, and fungi are among the best examples, and their power is being harnessed to develop new CCS strategies.
One approach has involved culturing algae in outdoor ponds to remove carbon dioxide directly from the atmosphere. In this approach, algae are grown in coastal desert areas, moving through a series of seawater ponds in a manner designed to maintain rapid growth. During this process, algae capture carbon dioxide from the atmosphere through photosynthesis. At the end of the process, algae are harvested and dried in the desert air. The drying process produces a highly stable biomass that can be compacted and buried under cool rock where it is predicted to remain stable for over 10,000 years. These processes have the added advantage of de-acidifying seawater, thereby increasing its capacity for absorbing further carbon dioxide from the atmosphere.
The natural carbon capture capabilities of cyanobacteria are also being utilised. Research teams have scoured the globe searching for cyanobacteria which thrive in hot springs and near volcanoes, where the water is high in dissolved carbon dioxide. Photobioreactor systems for growing the cyanobacteria have been developed which allow carbon dioxide to be captured directly from power stations and oil refineries, preventing it from being released into the atmosphere.
In addition, startups are emerging which transplant fungi into the soil of commercial tree plantations, exploiting the symbiotic relationships between the organisms and boosting the carbon sequestration capabilities of forests. Fungi pass essential nutrients from the soil to trees and receive carbon-containing molecules in return. These carbon-containing molecules are sequestered in the soil, increasing the capacity of the trees to capture carbon dioxide from the atmosphere. This strategy has been enhanced by a machine learning element which tells scientists which species of fungi will work best in different environmental conditions and with different tree species, illustrating the increasing importance of a cross-disciplinary approach.
Carbon capture at the molecular level
New strategies for CCS have been developed which focus on biochemical processes at the molecular level rather than exploiting the activity of microorganisms at the cellular level.
For example, research is ongoing to optimise carbonic anhydrase enzymes. Carbonic anhydrase is found in all living organisms and works to convert carbon dioxide into bicarbonate. This activity can be used on an industrial scale to capture carbon dioxide in flue gas as it exits combustion towers, reducing the amount of waste carbon dioxide gas which escapes into the atmosphere. Of course, to be used in combustion towers, these enzymes must be stable and effective at high temperatures. Thermostability has been achieved by utilising carbonic anhydrases extracted from thermophilic bacteria or by modifying the structure of the enzyme through processes such as enzyme cyclisation, which introduces extra covalent bonds between the polypeptide chains of the enzyme.
A further emerging biochemical strategy for carbon capture is one which integrates a novel pathway into the metabolism of E. coli, allowing the bacteria to convert carbon dioxide molecules into acetyl coenzyme A (acetyl-CoA). Acetyl-CoA is a key molecule in several cellular pathways, most famously in the Krebs cycle, as a precursor to lipids, amino acids and polysaccharides. As a result, acetyl-CoA is useful for the cellular production of, for example, biofuels and pharmaceuticals. This further demonstrates ways in which creativity and innovation in biotech can potentially contribute to reversing global warming due to previous carbon emissions, while also looking forward to reducing the carbon-intensive nature of production of consumer goods (see our earlier article here).
Although not used for direct carbon capture, an understanding of the biochemical processes performed by methanogens has exposed the utility of these microorganisms in the CCS ecosystem. Methanogens are anaerobic bacteria which naturally metabolise carbon dioxide and hydrogen to produce methane and water. Accordingly, rather than capture carbon dioxide themselves, these bacteria desorb carbon dioxide from other chemical carbon capture agents, such as amine-based compositions. This slows the rate at which the carbon capture agents become saturated such that they can be reused and recycled back into the process, thus improving the overall efficiency and sustainability of the carbon capture process. Although methane is traditionally considered a greenhouse gas itself, the “biomethane” produced by this process can be used in place of natural gas in generating electricity.
What about patents?
Biotech startups and companies with exciting new ideas in the CCS field will understandably want legal protection for their innovation. A newly identified or genetically modified microorganism which can efficiently capture carbon dioxide, for example, could itself be protected by a patent. Innovative formulations of the microorganism with enhanced stability or functionality could also be patentable. Protection could also be sought for methods of producing, storing, culturing and using the microorganism, bioreactors which efficiently harness its CCS power, and carbon-capture processes exploiting the microorganism or proteins derived therefrom.
As always with patent filing strategy, a balance must be struck between filing early enough to minimise compromising prior art disclosures and ensuring the patent application includes sufficient technical support for the key contributions of the invention. This is particularly the case in the biotech world, where demonstration of a technical effect often relies on experimental data.
An important consideration for applicants is the breadth they intend to achieve with their patent claims. If a sample of an innovative microorganism has been deposited at an appropriate institution, then achieving narrow protection for the specific microorganism may be straightforward, particularly if the advantages of the microorganism are disclosed, and ideally exemplified, in the application. However, efforts to extrapolate to cover a broader range of related microorganisms may require data for multiple related microorganisms or at least a scientific rationale enabling an extrapolation from the preferred microorganism representative of the advantages of the genus. Broad protection can be achievable for innovative formulations and methods, particularly if there are worked examples demonstrating the applicability of these inventions to a wide range of microorganisms.
The future
The ever-growing emphasis on gaining control of carbon dioxide emissions is evidently driving creativity in the biotech sector. Whether it is at the molecular or cellular level, researchers are developing ingenious methods and strategies which are applicable on an industrial scale. Harnessing natural processes in this way has the advantage of being less energy intensive and even more efficient than other CCS strategies. Hopefully, continued investment and innovation in the biotech sector will be a driving force behind the worldwide goal of decarbonisation.
