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Tutkimus / Research
​Cyanobacterial cultures in simulated Martian-like atmospheres
Adaptation of cyanobacteria to simulated Martian-like growth conditions

 
In the era when international space programs are developing plans for exploration missions to Mars, there emerges a question about the sustainable and relyable means to produce life support supplies – oxygen and food - for the crews of such missions on Mars: Would it be possible to produce these photosynthetic products in Martian conditions?  Natural local resources for photosynthesis do occur on Mars, at least to most extent: the atmosphere contains 95% of CO2, water is available either as ice in the underground or as bound to the minerals, and sun light is available to provide energy for the process. Most of the nutrients (P, K, Mg, Mn, Fe and micronutrients) needed for plant or bacterial growth are available in the Martian regolith, except for nitrogen, which is present only in 2% concentration in the Martian atmosphere. Thus, N is available in Mars in a very limited supply, and need to be tightly recycled (not allowed to evaporate back into the atmosphere). In Mars, all organisms must be cultivated in closed, protected environment(s), to protect them from the harsh environment (i.e. high UV-radiation, and large daily temperature variation, with ΔT up to 70 oC), and also to protect the environment from terrestrial contamination. In such enclosures, the Martian atmosphere, with its high (95%) CO2, with no O2 and low N2, and with very low pressure and low water content would need be used as the raw material for constructing the suitable gas environment for the growth facilities. In these conditions some cyanobacterial species would be the most durable initial photosynthesizer, to produce O2, and to mediate bioleaching of the mineral nutrients.

We study how the low air pressure, high CO2 content supplied at different concentrations and flow rates, and depletion of O2 and N2 in the atmosphere affect the cell growth, and O2, H2 and lipid production of selected cyanobacteria. These studies are theoretically aimed towards efficient and sustainable production of different life support supplies on Mars, but our preliminary results indicate that they provide novel means also for enhancing cyanobacterial H2 and lipid production in terrestrial applications. These studies are performed by using two well-known cyanobacterial species, i.e. Arthrospira sp. PCC 8005, a cyanobacterium that produces edible, highly nutritious biomass, and Anabaena cylindrica, which is known to grow well on plain basalt, in sterile water, with efficient bioleaching of nutrients, and also known to be an efficient biohydrogen producer.  The molecular bases of the cellular growth responses, particularly the adaptation of the photosynthetic, nitrogen fixation and lipid biosynthesis pathways to these conditions are analyzed.

We also study the effects of the litotrophic cyanobacteria, and of the above-mentioned growth conditions on the bioleaching of nutrients from rocky substrates. In addition, new geochemical methods (GeoTrapTM) is tested for the cycling of the nitrogenous nutrients.

 
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