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2018-03-05 - Colloque/Présentation - poster - Anglais - 1 page(s)

Van Camp Camille , Wattiez Ruddy , "The exopolysaccharide production by Cyanothece sp. PCC 7822 through an adapted metabolism" in ECO-BIO2018 : teamp up to accelerate global bioeconomy, Dublin, Irlande, 2018

  • Codes CREF : Biochimie (DI3112), Biologie moléculaire (DI3111), Microbiologie et protistologie [bacteriol.,virolog.,mycolog.] (DI3130)
  • Unités de recherche UMONS : Protéomie et Microbiologie (S828)
  • Instituts UMONS : Institut des Biosciences (Biosciences)
Texte intégral :

Abstract(s) :

(Anglais) Introduction The present research is a part of the Algotech project based on the production by Microalgae/Cyanobacteria in order to obtain high-added value products. In this context, we investigate exopolysaccharide production by Cyanobacteria because of their properties and applications in cosmetics, medicine or food industries. Methods Cyanothece sp. PCC 7822 was selected due to its ability to produce high rate of EPS. This cyanobacterium is an unicellular diazotrophic bacterium able to grow in continuous light or in light/dark cycle. This study focuses on the impact of culture conditions such as light intensity and cycle, nitrogen source, temperature on the EPS production. The effects on the bacterial metabolism and the EPS composition are analysed through different axes: phenotypical, biochemical, proteomics (mass spectrometry) and metabolomics (metabolic flux, NMR). Firstly, bacterial growth under light/dark cycles with different nitrogen sources was tested (N2, NO3-, NH4Cl and urea). Simultaneously, EPS production demonstrated by two types of alcian blue staining was analysed. Results As shown in the figure 1, Cyanothece sp. PCC 7822 grows similarly in presence of N2 or NO3- (17.6mM). Microscopic EPS examination with both specific dyes shows the production of large amount of extracellular EPS and suggests the presence of sulphated and carboxylic groups in EPS composition (Figure 2). Moreover, optimisations of EPS alkaline extraction and colorimetric quantitation protocols (phenol sulfuric and anthrone method) have been achieved. Discussion In the frame of a project implicated in microalgal energetics and biomass promotion, this work targets the EPS production by Cyanothece sp. PCC 7822 by using innovative processes. This bacterium Cyanothece sp. PCC 7822 shows its full potential by its EPS composed of carboxylic and especially sulphated group which is not the case with microalgae. In fine, this particular composition leads to saccharides with interesting industrial properties.


Mots-clés :
  • (Anglais) Cyanobacteria
  • (Anglais) exopolysaccharide
  • (Anglais) nitrogen source