title: Study of photorespiration in marine microalgae through the determination of glycolic acid using hydrophilic interaction liquid chromatography.
abstract: Determination of organic acids in intracellular extracts and in the cultivation media of marine microalgae aid investigations about metabolic routes related to assimilation of atmospheric carbon by these organisms, which are known by their role in the carbon dioxide sink. The separation of these acids was investigated by hydrophilic interaction liquid chromatography (HILIC) using isocratic elution with a mobile phase composed of 70:30 v/v acetonitrile/20 mmol/L ammonium acetate buffer (pH 6.8) and detection at 220 nm. HILIC allowed the determinations of glycolic acid, the most important metabolite for the evaluation of the photorespiration process in algae, to be made with better selectivity than that achieved by reversed phase liquid chromatography, but with less detectability. The concentration of glycolic acid was determined in the cultivation media and in intracellular extracts of the algae Tetraselmis gracilis and Phaeodactylum tricornutum submitted to different conditions of aeration: (i) without forced aeration, (ii) aeration with atmospheric air, and (iii) bubbling with N(2). The concentration of glycolic acid had a higher increase as the cultures were aerated with nitrogen, showing higher photorespiratory flux than that occurring in the cultures aerated with atmospheric air.
authors: Instituto de Química, Universidade de São Paulo, São Paulo, Brazil. rmmarilda@gmail.com
authors: Marilda
authors: M
authors: Rigobello-Masini
authors: José C P
authors: JC
authors: Penteado
authors: Maurício
authors: M
authors: Tiba
authors: Jorge C
authors: JC
authors: Masini
mesh_terms: D019069:Cell Respiration / Q000528:radiation effects; D000460:Chlorophyta / Q000737:chemistry* / Q000378:metabolism* / Q000528:radiation effects; D002853:Chromatography, Liquid / Q000379:methods*; D017377:Diatoms / Q000737:chemistry* / Q000378:metabolism* / Q000528:radiation effects; D006016:Glycolates / Q000032:analysis* / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D058086:Microalgae / Q000737:chemistry* / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D006016:Glycolates; C031149:glycolic acid