FROM CO2 TO POLYHYDROXYALKANOATES VIA CYANOBACTERIA

abstract

English

Carbon dioxide pollution is a topic that resonates strongly with society. More than 35 billion tons of CO2 were emitted to the atmosphere in 2021 (ref.1). Capture and usage of carbon dioxide together with reducing the CO2 emission per year could slow down warming of Earth surface.Polyhydroxyalkanoates(PHAs) are microbial biopolymers, occur as an intracellular granules and serve as an energy storage compound. They are biodegradable, UV resistant and biocompatibile2. PHA itself are fragile, the properties can be improved by incorporating other monomers into the structure resulting in in-vivo copolymer synthesis. PHA production is financially demanding. For heterotrophic bacteria waste materials serve as a carbon source. As the cyanobacteria are capable of oxygenic photosynthesis, they do not demand carbon source and for PHA synthesis they need only CO2 and light source.Cyanobacteria are phototrophic gram-negative bacteria belonging to the prokaryotes. They are ecologically extremely important as they are capable of oxygenic plant-like photosynthesis. Thanks to this ability cyanobacteria played a key role in biological and in geological history of our planet. Cyanobacteria synthesize many biologically active secondary metabolites such as glycogen, pigments, lipids or PHAs3. In this study two cyanobacterial strains from Synechocystis family were tested for copolymer production. The composition of co-polymer differs and the composition of co-polymers also varies depending on the precursor concentration. Synechocystis sp. PCC6803 and CCALA192 cultivated with acetate and γ-butyrolactone accumulated co-polymer 3HB-co-4HB with different fractions of 4HB. After several experiments CCALA192 seems to be very promising PHA producer. In air bubbled multicultivator we were able to gain up to 15-20 % of PHB in cell dry weight.Role of PHAs in cyanobacterial metabolism seems to be very complex. PHAs do not serve only as an energy storage compound, but also they help to survive the stress conditions. Deeper understanding together with well-adjusted cultivation conditions can make cyanobacteria the PHA-producers in present and future rich in CO2

PHA, cyanobacteria

ŠEDRLOVÁ, Z.; OBRUČA, S.

17. 4. 2023

XXIInd INTERDISCIPLINARY MEETING OF YOUNG LIFE SCIENTISTS

2336-7202

XXIInd INTERDISCIPLINARY MEETING OF YOUNG LIFE SCIENTISTS

Czech Chemical Society Symposium Series 21 (2) 67-122 (2022)

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108

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http://www.ccsss.cz/index.php/ccsss/issue/view/38