A photobioreactor system for precision cultivation of photoautotrophic microorganisms and for high‐content analysis of suspension dynamics

Abstract

Small-scale photobioreactors for cultivation of photoautotrophic microbes are required for precise characterization of the growth parameters of wild-type and engineered strains of these organisms, for their screening, and for optimization of culture conditions. Here, we describe the design and use of a flat-cuvette photobioreactor that allows accurate control of culture irradiance, temperature, pH, and gas composition combined with real-time monitoring by a built-in fluorometer and densitometer. The high-power LED light source generates precise irradiance levels that are programmed by user-designed protocols. The irradiance, temperature, and gas composition may be static or dynamically modulated, while optical density and pH may be stabilized in turbidostat and pH-stat modes, respectively. We demonstrate that the instrument is able to detect minute variations of growth caused, for example, by sudden dilution or by circadian rhythms. The sensitivity of the instrument is sufficient to monitor suspension optical density as low as 10(-2). This newly designed photobioreactor can significantly contribute to the study and use of photoautotrophic microbes in systems biology and biotechnology.

Ultradian metabolic rhythm in the diazotrophic cyanobacterium Cyanothece sp. ATCC 51142

“…Cyanothece was grown in flat-panel photobioreactors with highly time-resolved, automated sampling to follow cyclic processes over days and weeks (19). Before the experiment shown in Fig.…”

“…For growing and real-time monitoring of cultures, we used flat panel photobioreactors (FMT-150, Photon Systems Instruments), which were described in detail previously (19). Unless specified otherwise, the culture temperature was stabilized at 36.0 ± 0.3°C, irradiance was 130-160 μmol photons m −2 ·s −1 of red light (∼627 nm) supplemented with 25 μmol photons m −2 ·s −1 of cool white or blue light (∼455 nm).…”

Optimization of Hydraulic Retention Time and Biomass Concentration in Microalgae Biomass Production from Treated Sewage with a Membrane Photobioreactor

“…Secondary treatment effluent from activated sludge processes could serve as a good cultivation medium because it also contains high levels of carbonate, as well as nitrogen and phosphorus. However, nutrient contents in wastewater and treated wastewater are much lower than those in cultivation media that has typically been used in past studies of microalgae cultivation [4][5][6][7][8].…”

Oscillators for Modelling Circadian Rhythms in Cyanobacteria Growth

“…Particularly the carbon dioxide concentration changes can be applied in the experiments. As the model output the optical density of cyanobacteria culture in 735 nm, as a parameter proportional to concentration of cyanobacteria culture, is used (Nedbal et al, 2008). …”