2.5. Analytical methods
Volatile suspended solids (VSS) and DIC concentrations were determined according to methods 2540 and 4500 of Standard Methods [23], respectively. DO was determined by means of a portable DO meter (Thermo Orion 3-Star RDO). CO2 and O2 concentrations in the gas phase were determined by means of a PBI Dansensor Checkmate 9900 CO2/O2 Headspace. During the operation of the continuous photobioreactor connected to bubble column, gas composition was determined through a gas chromatograph with thermal conductivity detector (Perkin Elmer Clarus 500). The gas/liquid mass transfer coefficient for O2 (KLaO2) was measured using the dynamic gassing-in method [24], in
seawater without biomass. CO2 mass transfer coefficient (KLaCO2) was calculated from values determined for O2, through the relation KLaCO2 ¼ 0; 9KLaO2