Experimental and Modeling Analysis of Synechocystis sp. PCC 6803 growth

[EN] Background/Aims: The influence of different parameters such as temperature, irradiance, nitrate concentration, pH, and an external carbon source on Synechocystis PCC 6803 growth was evaluated. Methods: 4.5-ml cuvettes containing 2 ml of culture, a high-throughput system equivalent to batch cultures, were used with gas exchange ensured by the use of a Parafilm TM cover. The effect of the different variables on maximum growth was assessed by a multi-way statistical analysis. Results: Temperature and pH were identified as the key factors. It was observed that Synechocystis cells have a strong influence on the external pH. The optimal growth temperature was 33 ° C while light-saturating conditions were reached at 40 E m –2 s –1 . Conclusion: It was demonstrated that Synechocystis exhibits a marked difference in behavior between autotrophic and glucose-based mixotrophic conditions, and that nitrate concentrations did not have a significant influence, probably due to endogenous nitrogen reserves. Furthermore, a dynamic metabolic model of Synechocystis photosynthesis was developed to gain insights on the underlying mechanism enabling this cyanobacterium to control the levels of external pH. The model showed a coupled effect between the increase of the pH and ATP production which in turn allows a higher carbon fixation rate.This work was financially supported by FCT (SFRH/BPD/37045/2007), POCI 2010 (III Quadro Comunitario de Apoio), Generalitat Valenciana (BFPI/2007/283), Ministerio de Educacion y Ciencia de Espana through the program Juan de la Cierva and project ArtBioCom (TIN2009-12359), EU FP7-KB-BE-2007 project TarPol (contract No. 212894), EU FP6-NEST-2005 project BioModularH2 (contract No. 043340), and AccOes Integradas Luso-Espanholas 2009 (E-44/09).Lopo, M.; Montagud, A.; Navarro-Peris, E.; Cunha, I.; Zille, A.; Fernández De Córdoba Castellá, PJ.; Moradas-Ferreira, P.... (2012). Experimental and Modeling Analysis of Synechocystis sp. PCC 6803 growth. Journal of Molecular Microbiology and Biotechnology. 22(2):71-82. https://doi.org/10.1159/000336850718222