title: Optimisation of culture parameters for exopolysaccharides production by the microalga Rhodella violacea.
abstract: A unicellular Rhodophyte was identified by sequencing of its 18S rRNA encoding gene as belonging to the Rhodella violacea specie. With the objective to optimise the production of biomass and exopolysaccharide by this strain, effects of irradiance, pH and temperature on its photosynthetic activity were investigated. In a second time a stoichiometric study of the well-known f/2 medium led to its supplementation in N and P to increase biomass and then exopolysaccharide yields when the strain was cultivated in photobioreactors. The use of optimal conditions of culture (irradiance of 420 μE/m(2)/s, pH of 8.3 and temperature of 24 °C) and f/2 supplemented medium led to significant increases of biomass and exopolysaccharide productions. The structural characterisation of the produced exopolysaccharide revealed that it was sulphated and mainly composed of xylose. The different culture conditions and culture media tested had no significant impact on the structure of produced exopolysaccharides.
authors.affiliation: Clermont Université, Université Blaise Pascal, Institut Pascal UMR CNRS 6602, 24 Avenue des Landais BP 206, 63174 Aubière cedex, France.
authors.forename: Aurore
authors.initials: A
authors.lastname: Villay
authors.affiliation: Clermont Université, Université Blaise Pascal, Institut Pascal UMR CNRS 6602, 24 Avenue des Landais BP 206, 63174 Aubière cedex, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Laroche
authors.affiliation: Clermont Université, Université Blaise Pascal, Laboratoire "Microorganismes: Génome et Environnement", UMR CNRS 6023, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Diane
authors.initials: D
authors.lastname: Roriz
authors.affiliation: Clermont Université, Université Blaise Pascal, Laboratoire "Microorganismes: Génome et Environnement", UMR CNRS 6023, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Hicham
authors.initials: H
authors.lastname: El Alaoui
authors.affiliation: Clermont Université, Université Blaise Pascal, Laboratoire "Microorganismes: Génome et Environnement", UMR CNRS 6023, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Frederic
authors.initials: F
authors.lastname: Delbac
authors.affiliation: Clermont Université, Université Blaise Pascal, Institut Pascal UMR CNRS 6602, 24 Avenue des Landais BP 206, 63174 Aubière cedex, France. Electronic address: philippe.michaud@univ-bpclermont.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Michaud
mesh_terms: D018533:Biomass; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D058086:Microalgae / Q000378:metabolism*; D058433:Photobioreactors; D010788:Photosynthesis; D010802:Phylogeny; D011134:Polysaccharides / Q000096:biosynthesis*; D012337:RNA, Ribosomal, 18S / Q000378:metabolism; D000461:Rhodophyta / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors; D014994:Xylose / Q000737:chemistry
chemical_list: D003470:Culture Media; D011134:Polysaccharides; D012337:RNA, Ribosomal, 18S; D014994:Xylose
keywords: Exopolysaccharide; Rhodella violacea