Exploiting the unique abilities of algae and bacteria to capture atmospheric carbon dioxide
Project duration: June 2023–June 2026
Mr Dion Frampton
Kim Lee-Chang, Matthew Taylor, Anusuya Willis, Nawshad Haque and Eileen Lee.
Owing to their fast rates of carbon fixation (10–50 times faster than terrestrial plants) and potential for rapid and scalable production, algae and cyanobacteria are promising biological agents of accelerated carbon dioxide removal (CDR). Importantly, these organisms also have the capacity to biosynthesise intracellular recalcitrant carbon (AIR-C) compounds – macromolecules with high durability – that are stored long term in aquatic systems.
Intensive production of algae for the purpose of CDR has exciting potential, both in Australia and more broadly, yet there are significant barriers to realising the potential. Fundamental knowledge of AIR-C chemistry, responsible algal species, quantities, and the biosynthetic processes involved is relatively poor. Marine species are particularly underrepresented in this knowledge base, yet their potential contribution to the global biological carbon capture capacity is significant. There are also critical questions that need to be answered. How much carbon can be sequestered and how durable is sequestration?
A promising opportunity exists to assess, quantify, and process AIR-C compounds, conduct life cycle analyses (LCA) of the system process, and explore avenues for accelerated biosynthesis (via intra and extracellular routes). Indeed, the application of algal species with characterised and enhanced AIR-C production for the primary purpose of CDR will have many avenues to knowledge generation and advancement, as well as potential benefits for Australia that include creation of new carbon-based businesses and technologies, expansion of our overall carbon storage potential, and access to carbon offset methods with integrity.
Our aim is to directly address the critical questions and knowledge gaps that are preventing advancement in this field.
We’ll begin with assessment and selection of appropriate species for effective carbon fixation and scalable production of AIR-C, followed by AIR-C biosynthesis and new or improved routes for biosynthetic conversion, effective downstream processing and value adding, and LCA of the process to determine its application to CDR.
With an initial focus on contained cultivation systems, we’ll exploit the diversity of photosynthetic algae and cyanobacteria to accelerate the biosynthetic conversion of atmospheric CO2 into long-lived AIR-C compounds such as aliphatic polymers and related macromolecules. In doing so, we’ll advance new and improved species, products and processes for accelerated CDR and other applications (e.g., algae mariculture industry). The developed technologies will also ideally link with other developing CDR-related technologies and processes such as direct air capture (DAC) and CO2 photobioreactor technology.
Perhaps the greatest challenge for the project is the inescapable complexity of interactions between multiple disciplines, and complex science within each discipline, combined with an early state of current knowledge for algae in this application area. Overcoming challenges associated with scalability, cost of production, and verifiability will be critical as the technology matures. Navigating the regulatory environment will also be a challenge if/when approaches involving genetic modification require field testing.
Apart from the broad innovation challenges, there are inherent technical risks in any strategy involving metabolic and molecular manipulation, including that of algae. This is largely due to the complex multidisciplinary approach required to find the species/products/processes that warrant further investigation, the complexity of the biosynthetic pathways involved, the lack of molecular and metabolic knowledge resources for algae, and the varied responses of different biological systems. With a robust research design and contingency plans, and expertise across microbial culturing, photobioreactor technologies and scale-up, organic chemistry, molecular/metabolic characterisation and LCA, the project team are fully equipped to meet these challenges.
- Xu et al. (2019). Progress, challenges and solutions of research on photosynthetic carbon sequestration efficiency of microalgae. https://www.sciencedirect.com/science/article/abs/pii/S136403211930262X?via%3Dihub
- Zhou et al. (2017). Bio-mitigation of carbon dioxide using microalgal systems: Advances and perspectives. https://www.sciencedirect.com/science/article/abs/pii/S1364032117303817?via%3Dihub