Featured Lendület Researcher: Szilvia Zita Tóth
Szilvia Zita Tóth, Director of the Institute of Plant Biology at the HUN-REN Biological Research Centre in Szeged and Head of the Laboratory for Molecular Photobioenergetics, is now conducting research on the hydrogen-producing capacity of green algae in her second Momentum (Lendület) grant project. This capacity may be harnessed for human energy generation in the future. In the long term, it may even become possible to utilise the direct electrical current production of algae. This would enable energy to be generated without the emission of greenhouse gases, while the algae would also absorb carbon dioxide through photosynthesis. In addition, the biomass of the algae could also be utilised.
Green algae are capable of producing hydrogen as part of their photosynthetic processes. Under natural conditions, this ability is primarily activated when they are suddenly exposed to light after being in dark, oxygen-free conditions. In such cases, the light energy already excites the algae’s photosynthetic apparatus, but CO₂ fixation has not yet begun. This transitional state lasts only a few minutes; however, even during this time, the algae need a way to get rid of the excess excitation energy.
Szilvia Zita TóthA potential source of green energy
“Hydrogen production acts as a kind of safety valve for algae: it allows them to release excess energy,” says Tóth, Head of the Laboratory for Molecular Photobioenergetics at the Biological Research Centre in Szeged. “The ability to produce hydrogen was discovered nearly a century ago, and ever since, researchers have been trying to extend its duration and improve its efficiency. This is, in fact, a potential source of green energy: if the process could be sustained continuously and efficiently, we could use algae to produce hydrogen for energy generation.”
Tóth has now been awarded support from the Momentum Programme for the second time. During the first five years of the grant, her team worked on developing a hydrogen production process that is sustainable, efficient, and less harmful to algae than previously established approaches. They have also succeeded in patenting the method they developed. The main goal of the new project
is to better understand the physiological basis of hydrogen production and the factors that limit it.
To this end, they are employing targeted and untargeted metabolomic analyses as well as transcriptomics, alongside a wide range of physiological investigations.
In addition, they are working intensively on a new line of research: the use of green algae in biophotovoltaic systems. The aim of this project is to expand the potential applications of green algae in the fields of sustainable electricity generation and biocatalysis. For their experiments, the researchers use a recently identified strain of Parachlorella kessleri, which exhibits outstanding exoelectrogenic activity – that is, it is capable of exporting electrons from the cell and reducing certain components in its environment.
New horizons in sustainable energy production
The research group’s goal is, on the one hand, to investigate the physiological role of exoelectrogenesis and, on the other, to identify the physiological limiting factors of biophotovoltaic systems in order to achieve sustained (days-long) electricity generation and to develop a continuously operating system. In addition, they aim to explore the applicability of exoelectrogenesis in biocatalysis by linking the exoelectrogenic activity of algae to specific enzymes. This concept offers an alternative to earlier biocatalytic processes which rely on costly external electron donors. Achieving these objectives will open up new horizons in the fields of sustainable energy production and biotransformation processes, which could lead to sustainable electricity generation as well as the environmentally friendly production of valuable chemicals and fuels.
“The algae-based electricity generation system currently operates only under laboratory conditions and on a small scale. A great deal of research will still be required before it can be put into practical use,” says Tóth. “At the same time, we must already be very careful about what results we publish and what we present at conferences. Many discoveries may have economic value in the future, so we are continuously considering the possibility of patenting them as well.”
Algae-based energy production – whether through the use of hydrogen or the exploitation of the exoelectrogenic capacity of algae – offers significant advantages in several respects.
These processes do not produce greenhouse gases, and, through photosynthesis, algae are capable of fixing substantial amounts of carbon dioxide from the atmosphere. Algal biomass can be used as a natural source of nutrients or as a biostimulant in agriculture, and may even be suitable for human consumption. The research group’s goal is to integrate algae into circular economic processes that are essential from a sustainability perspective.