title: CAH1 and CAH2 as key enzymes required for high bicarbonate tolerance of a novel microalga Dunaliella salina HTBS.
abstract: Outdoor microalgal cultivation with high concentration bicarbonate has been considered as a strategy for reducing contamination and improving carbon supply efficiency. The mechanism responsible for algae's strong tolerance to high bicarbonate however, remains not clear. In this study, we isolated and characterized a strain and revealed its high bicarbonate tolerant mechanism by analyzing carbonic anhydrase (CA). The strain was identified as Dunaliella salina HTBS with broad temperature adaptability (7-30°C). The strain grew well under 30% CO2 or 70gL(-1) NaHCO3. In comparison, two periplasm CAs (CAH1 and CAH2) were detected with immunoblotting analysis in HTBS but not in a non-HCO3(-)-tolerant strain. The finding was also verified by an enzyme inhibition assay in which only HTBS showed significant inhibition by extracellular CA inhibitor. Thus, we inferred that the extracellular CAH1 and CAH2 played a multifunctional role in the toleration of high bicarbonate by HTBS.
authors.affiliation: Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, PR China.
authors.forename: Yuyong
authors.initials: Y
authors.lastname: Hou
authors.affiliation: Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, PR China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, PR China.
authors.forename: Shulin
authors.initials: S
authors.lastname: Chen
authors.affiliation: Shandong Jinjing Biotechnology Co., Ltd., Shandong 261313, PR China.
authors.forename: Yubin
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, PR China. Electronic address: chen_fj@tib.cas.cn.
authors.forename: Fangjian
authors.initials: F
authors.lastname: Chen
mesh_terms: D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism*; D001639:Bicarbonates / Q000378:metabolism*; D002256:Carbonic Anhydrases / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D058086:Microalgae / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D008854:Microscopy, Electron; D010802:Phylogeny; D013696:Temperature; D016823:Volvocida / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D020418:Algal Proteins; D001639:Bicarbonates; D007527:Isoenzymes; D002256:Carbonic Anhydrases
keywords: Bicarbonate; Carbonic anhydrase; Dunaliella salina HTBS; Inorganic carbon fixation