title: Gas Transfer Controls Carbon Limitation During Biomass Production by Marine Microalgae.
abstract: This study presents the first in-depth analysis of CO2 limitation on the biomass productivity of the biofuel candidate marine microalga Nannochloropsis oculata. Net photosynthesis decreased by 60% from 125 to 50 μmol O2 L(-1)h(-1) over a 12 h light cycle as a direct result of carbon limitation. Continuous dissolved O2 and pH measurements were used to develop a detailed diurnal mechanism for the interaction between photosynthesis, gas exchange and carbonate chemistry in the photo-bioreactor. Gas exchange determined the degree of carbon limitation experienced by the algae. Carbon limitation was confirmed by delivering more CO2 , which increased net photosynthesis back to its steady-state maximum. This study highlights the importance of maintaining replete carbon concentrations in photo-bioreactors and other culturing facilities, either by constant pH operation or preferably by designing a feedback loop based on the dissolved O2 concentration.
authors.affiliation: Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales 2007 (Australia).
authors.forename: Bojan
authors.initials: B
authors.lastname: Tamburic
authors.affiliation: Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales 2007 (Australia).
authors.forename: Christian R
authors.initials: CR
authors.lastname: Evenhuis
authors.affiliation: Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales 2007 (Australia).
authors.forename: David J
authors.initials: DJ
authors.lastname: Suggett
authors.affiliation: Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales 2007 (Australia).
authors.forename: Anthony W D
authors.initials: AW
authors.lastname: Larkum
authors.affiliation: Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales 2007 (Australia).|Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie DD2 5DA (United Kingdom).
authors.forename: John A
authors.initials: JA
authors.lastname: Raven
authors.affiliation: Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales 2007 (Australia).
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Ralph
mesh_terms: D018533:Biomass; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D058086:Microalgae / Q000254:growth & development / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D058009:Stramenopiles / Q000254:growth & development / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide; D002244:Carbon; D010100:Oxygen
keywords: biomass; carbon dioxide fixation; kinetics; photosynthesis; renewable resources