Periodic Reporting for period 2 - PhotoSynH2 (Photosynthetic electron focusing technology for direct efficient biohydrogen production from solar energy)
Período documentado: 2023-10-01 hasta 2025-01-31
Nature’s most powerful energy converter, photosynthesis, offers an elegant blueprint. In plants, algae, and some bacteria, sunlight is used to split water into oxygen, protons, and electrons, which are then used to create energy-rich compounds. Certain algae can even produce hydrogen directly, but this process is naturally inefficient and inhibited by its own oxygen byproduct.
The PhotoSynH2 project core idea is to create a technology we call ‘photosynthetic electron focusing’, where the high-energy electrons from water splitting are channelled directly towards a highly efficient, engineered hydrogen-producing enzyme, bypassing the native metabolism.
A key innovation is the use of custom-designed [FeFe] hydrogenase enzymes as catalysts, which avoid the need for expensive and rare metals like platinum. The project is engineering these enzymes for higher activity and improved tolerance to oxygen. To further protect the system, the host bacteria are also being engineered to consume intracellular oxygen.
Sriven by a detailed techno-economic analysis, in addition to hydrogen, the engineered cyanobacteria will co-produce astaxanthin, a high-value antioxidant pigment used in nutraceuticals and cosmetics. This dual-production strategy dramatically improves the economic viability of the entire process.
The project aims to demonstrate this technology in custom-designed photobioreactors, scaling up to a 1,300-litre system. To ensure sustainability, the engineered strains are also being fortified for robust growth in challenging conditions, such as high-salinity seawater or nutrient-rich wastewater. By combining these innovations, PhotoSynH2 aims to create a biological hydrogen production platform that is not only environmentally sustainable but also economically competitive.
The PhotoSynH2 project core idea is to create a technology we call ‘photosynthetic electron focusing’, where the high-energy electrons from water splitting are channelled directly towards a highly efficient, engineered hydrogen-producing enzyme, bypassing the native metabolism.
A key innovation is the use of custom-designed [FeFe] hydrogenase enzymes as catalysts, which avoid the need for expensive and rare metals like platinum. The project is engineering these enzymes for higher activity and improved tolerance to oxygen. To further protect the system, the host bacteria are also being engineered to consume intracellular oxygen.
Sriven by a detailed techno-economic analysis, in addition to hydrogen, the engineered cyanobacteria will co-produce astaxanthin, a high-value antioxidant pigment used in nutraceuticals and cosmetics. This dual-production strategy dramatically improves the economic viability of the entire process.
The project aims to demonstrate this technology in custom-designed photobioreactors, scaling up to a 1,300-litre system. To ensure sustainability, the engineered strains are also being fortified for robust growth in challenging conditions, such as high-salinity seawater or nutrient-rich wastewater. By combining these innovations, PhotoSynH2 aims to create a biological hydrogen production platform that is not only environmentally sustainable but also economically competitive.
During its second period, the PhotoSynH2 project transitioned from foundational tool-building to demonstrating integrated biological systems, marking significant progress across all areas of its research programme.
A major breakthrough was the demonstration of biological hydrogen production in engineered Synechocystis strains without the need for external chemical activation. The systems biology and strain engineering team at Uppsala University (WP3) achieved this by successfully co-expressing both an engineered [FeFe] hydrogenase and its specific maturation enzymes. This creates a self-sufficient biological system where the cell can assemble its own active catalyst in vivo, a critical step towards industrial feasibility.
This achievement was built upon the advanced genetic toolkit developed by the CSIC team (WP1). They designed and validated a powerful suite of synthetic biology tools, including novel CRISPR-based systems for gene activation and repression, as well as RNA-based regulators. These function like precise genetic switches, allowing the consortium to fine-tune metabolic pathways, downregulate competing processes, and control the expression of the project's engineered components.
The hydrogen-producing enzyme itself was the focus of the second research team at Uppsala University, specialising in biocatalysis (WP4). This team identified novel [FeFe] hydrogenases from nature and, through rational protein engineering, created new variants with significantly enhanced catalytic activity. Crucially, they engineered enzymes with improved tolerance to oxygen, a key bottleneck that has long hampered biological hydrogen production. This work has already resulted in a peer-reviewed publication in a high-impact journal.
To create a more resilient industrial chassis, the i3S team in Portugal (WP5) successfully engineered Synechocystis strains with enhanced tolerance to high-salinity conditions, demonstrating robust growth in media mimicking seawater. This innovation reduces the reliance on precious fresh water. Moreover, to create an intracellular environment appropriate for hydrogenases activity/H2 production, Synechocystis strains were further engineered to harbor oxygen scavenging devices. Taking a complementary approach to sustainability, the CNR team in Italy (WP6) demonstrated that the cyanobacteria could be cultivated using nutrient-rich wastewater from a municipal treatment plant. Their experiments showed not only successful growth but also sustained, long-term hydrogen production, showcasing a truly circular economy model.
Following a detailed techno-economic analysis, the project strategically pivoted to include the co-production of a high-value pigment. The CSIC team (WP2) is leading the work to integrate the genetic pathway for astaxanthin synthesis into the cyanobacterial host, aiming to create a highly profitable biorefinery.
Finally, the project's hardware has seen substantial development. The M2M team in Italy (WP6) designed an improved 1,300-litre multiplate photobioreactor (MPL). A 150-litre first improved MPL pilot version has been constructed and installed at the CNR site for outdoor testing under real-world solar conditions. In parallel, Algreen in the Netherlands (WP6) has identified a potential industrial site for future large-scale deployment and has mapped the complex regulatory pathway needed to operate with genetically engineered microorganisms at this scale in Europe.
A major breakthrough was the demonstration of biological hydrogen production in engineered Synechocystis strains without the need for external chemical activation. The systems biology and strain engineering team at Uppsala University (WP3) achieved this by successfully co-expressing both an engineered [FeFe] hydrogenase and its specific maturation enzymes. This creates a self-sufficient biological system where the cell can assemble its own active catalyst in vivo, a critical step towards industrial feasibility.
This achievement was built upon the advanced genetic toolkit developed by the CSIC team (WP1). They designed and validated a powerful suite of synthetic biology tools, including novel CRISPR-based systems for gene activation and repression, as well as RNA-based regulators. These function like precise genetic switches, allowing the consortium to fine-tune metabolic pathways, downregulate competing processes, and control the expression of the project's engineered components.
The hydrogen-producing enzyme itself was the focus of the second research team at Uppsala University, specialising in biocatalysis (WP4). This team identified novel [FeFe] hydrogenases from nature and, through rational protein engineering, created new variants with significantly enhanced catalytic activity. Crucially, they engineered enzymes with improved tolerance to oxygen, a key bottleneck that has long hampered biological hydrogen production. This work has already resulted in a peer-reviewed publication in a high-impact journal.
To create a more resilient industrial chassis, the i3S team in Portugal (WP5) successfully engineered Synechocystis strains with enhanced tolerance to high-salinity conditions, demonstrating robust growth in media mimicking seawater. This innovation reduces the reliance on precious fresh water. Moreover, to create an intracellular environment appropriate for hydrogenases activity/H2 production, Synechocystis strains were further engineered to harbor oxygen scavenging devices. Taking a complementary approach to sustainability, the CNR team in Italy (WP6) demonstrated that the cyanobacteria could be cultivated using nutrient-rich wastewater from a municipal treatment plant. Their experiments showed not only successful growth but also sustained, long-term hydrogen production, showcasing a truly circular economy model.
Following a detailed techno-economic analysis, the project strategically pivoted to include the co-production of a high-value pigment. The CSIC team (WP2) is leading the work to integrate the genetic pathway for astaxanthin synthesis into the cyanobacterial host, aiming to create a highly profitable biorefinery.
Finally, the project's hardware has seen substantial development. The M2M team in Italy (WP6) designed an improved 1,300-litre multiplate photobioreactor (MPL). A 150-litre first improved MPL pilot version has been constructed and installed at the CNR site for outdoor testing under real-world solar conditions. In parallel, Algreen in the Netherlands (WP6) has identified a potential industrial site for future large-scale deployment and has mapped the complex regulatory pathway needed to operate with genetically engineered microorganisms at this scale in Europe.
The PhotoSynH2 project has produced several results that advance the state-of-the-art in biotechnology and green energy. The creation of a self-activating bio-hydrogen system marks a critical step forward, moving beyond laboratory methods that require chemical synthesis of cofactors and toward a more autonomous and industrially viable biological catalyst. Furthermore, the project has delivered superior catalysts in a robust host that can thrive in seawater or wastewater and has demonstrated sustained photobiological hydrogen evolution over several weeks in a lab-scale reactor, a key proof-of-concept for achieving continuous production in large-scale outdoor systems.