RESEARCH
Primary Areas of Interest
ASCORBATE (VITAMIN C)
IN PLANTS
Physiological roles, transport and metabolism of ascorbate
Ascorbate is an essential vitamin for humans, which is of plant origin and fulfills various roles both in mammalian and plant cells. Szilvia Z. Tóth and her group focus on the biosynthesis, transport and physiological roles of ascorbate in plants and green algae. Their results may ultimately contribute to increasing the ascorbate contents of crops.
SINGLE CELL ANALYSIS FOR GREEN ALGAE
Combination of microfluidics and chl a fluorescence imaging
Our approach is based on microfluidics, which allows the trapping of a small number or unique algal cells for several days, during which morphological examinations can be performed by microscopy. We combined this with chlorophyll-a fluorescence measurements that provide valuable information on photosynthetic activity.
H2 PRODUCTION
BY GREEN ALGAE
Establishment of an entirely green renewable energy production system
Hydrogen gas (H2) is a clean energy carrier that features zero carbon emissions during its combustion. Green algae are capable of generating H2 during photosynthesis by their highly active [Fe-Fe]-type hydrogenases; for this reason, the photoproduction of H2 could theoretically be the most efficient way of converting sunlight into chemical energy by biological systems.
ELECTRIC CURRENT PRODUCTION BY GREEN ALGAE
The EnergUP - MSCA project
Renewable energy sources are of high interest due to the shortage of fossil energy sources and the present energy crisis. One possible way to obtain green energy is the use of photosynthetic organisms to directly produce electricity in various bio-photovoltaic devices (BPVs).
Alga-based current production could be advantageous for several reasons, such as 1) being an environmental friendly way of sunlight energy conversion, 2) the potential to decrease the energy consumption of alga biomass production by including self-sustainable bioreactors in the production system. The fact that these photosynthetic algae capture CO2 while produce O2, is a further positive aspect.
Although BPVs provide a promising alternative for producing energy, the efficiency of the available systems are inadequate for industrial use. The goal of the Marie Skłodowska Curie Action EnergUP project is to improve the alga-based, light-dependent current production by targeting various aspects of the process.
Specifically, we aim at (1) enhancing the electron flow from the alga cells towards the electrodes by altering photosynthetic electron transport processes, (2) investigating whether the cell wall represents a barrier for electron transfer (3) establishing an alga cell immobilization method for a more efficient current production.
We designed a small-scale BPV device to carry out measurements on up to eight samples simultaneously. This setup enables varying the light intensity and to test its effect on current production. This small-scale sample holder requires a small culture volume and it is designed to carry out short term measurements (up to one hour).
We also constructed a bio-photovoltaic device for liquid cell cultures for long-term measurements. This experimental setup enables measuring the light-induced current production for several days and it does not require specific pretreatment of the cell culture, such as harvesting or concentrating. The obtained currents are outstanding, i.e., several times higher than reported so far, and this experimental system does not impose severe stress on the alga cultures. We use the liquid culture BPV to test various photosynthetic mutants.
By employing these newly developed BPV devices and mutant strains, we have succeeded in substantially increasing the rate of current production. We have also discovered that there is a large variability between wild-type strains in terms of current producing capacity. In the frame of the present project, various alga species are screened using our newly developed bio-photovoltaic setups; a strain with high current production capacity has already been identified.
Recent publication: Petrova et al., Enhancing biophotovoltaic efficiency: Study on a highly productive green algal strain Parachlorella kessleri MACC-38. Bioresource Technology (in press)
