Conclusions
We have provided here a detailed study of temperature impacts onArthrospira platensis biomass production in semi-continuous operation. This temperature study of Arthrospira platensis in photobioreactor cultivations demonstrates that temperatures in the 20 - 35 °C range are favorable for achieving consistent productivities, though long term exposure to 35 °C caused some modest changes in productivity and more obvious changes in pigmentation. Exposure to simulated conditions for summer temperature profiles for Southwest Florida shows some issues for the most extreme conditions but a general tolerance for the short term, mid-day exposures to higher temperatures. The response of the cultures to abrupt changes in temperature is immediate for biomass production and quantitatively consistent with the temperature dependence observed for Pmax in smaller scale photosynthetic response experiments. Pigment variations with abrupt changes in temperature occurrs on a time scale that was essentially the same as that expected for turnover of the cell population under semi-continuous operation. No other acclimation effects were identified. These results all involve annual average irradiance conditions. Extension of this study to higher irradiance conditions in the summer may cause additional issues in combination with extreme temperature exposures, high or low. Productivity modeling based on photosynthetic parameters derived from periodic sampling of the cultures provides excellent agreement with experiment and consistency with the performance of large scale outdoor PBR cultivations.