In order to obtain growth characteristics of P. angustum S14 in batch mode, and in conditions equivalent to those used in the continuous culture experiment, we performed duplicate growth curves in the light (406.7 μE · m–2 · s–1) and in the dark using the photobioreactors, the “high” substrate medium and the same parameters used in the continuous culture experiments. Growth was estimated from OD620 nm measurements as above.
The optimum pH for growth was tested in duplicate using the “high” substrate medium to which buffers MES (Sigma-Aldrich; for pH 5.5–6.5), HEPES (Sigma-Aldrich; for pH 7.0–8.0), or AMPSO (Sigma-Aldrich; for pH 8.5–10.0) were added at 2.0 mg/ml. pH was adjusted to a 5.5–10.0 range using 25% (v/v) concentrated HCl or 1 N NaOH. Growth was followed in 24 well plates (Evergreen Scientific, USA) incubated at 25°C in the dark at 100 rpm. OD620 nm measurements were obtained using a Paradigm™ Multi-mode Detection Platform (Molecular Devices, USA).
The optimum pH for growth was tested in duplicate using the “high” substrate medium to which buffers MES (Sigma-Aldrich; for pH 5.5–6.5), HEPES (Sigma-Aldrich; for pH 7.0–8.0), or AMPSO (Sigma-Aldrich; for pH 8.5–10.0) were added at 2.0 mg/ml. pH was adjusted to a 5.5–10.0 range using 25% (v/v) concentrated HCl or 1 N NaOH. Growth was followed in 24 well plates (Evergreen Scientific, USA) incubated at 25°C in the dark at 100 rpm. OD620 nm measurements were obtained using a Paradigm™ Multi-mode Detection Platform (Molecular Devices, USA).