Increasing PHA production in cyanobacteria by mixotrophic cultivation

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angličtina

Cyanobacteria are phototrophic gram-negative bacteria capable of oxygenic photosynthesis. They are able to synthetize polyhydroxyalkanoates (PHA). They do not require costly organic substrate and, oppositely, cyanobacteria can fix CO2. PHA serve as carbon and energy source in form of intracellular granules. PHA help cyanobacteria to survive stress conditions. In this work we demonstrated that stress conditions lead to the highest yields of PHA. Two cultures from genera Synechocystis were used. Multiple stressors were applied on cultures, stressors include PHA precursors. Cultivation with the same PHA precursors in same concentration led to 1,6-higher amount of PHA when multicultivator was used. The highest amount of PHA reached the 25 % of PHA in dry biomass. Strains are capable of copolymer synthesis in presence of its precursor. Synechocystis sp. PCC 6803 cultivated with γ-butyrolactone accumulated copolymer of 3-hydroxybutyrate (44 %) and 4-hydroxybutyrate (56 %). The total amount of PHA as well as yield of biomass was lower than in a control due to the toxic properties of γ-butyrolactone. This study was funded by the project GA19- 19-29651L of the Czech Science Foundation (GACR), by the Austrian Science Fund (FWF), project I 4082-B25, by Brno Ph.D. Talent – Funded by the Brno City Municipality.

cyanobacteria, Synechocystis, polyhydroxyalkanoates

ŠEDRLOVÁ, Z.; SLANINOVÁ, E.; FRITZ, I.; DAFFERT, C.; OBRUČA, S.

1. 12. 2021

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