Production and monitoring of biomass and fucoxanthin with brown microalgae under outdoor conditions

The effect of light on biomass and fucoxanthin productivities was studied in two microalgae, Tisochrysis lutea and Phaeodactylum tricornutum. High and low biomass concentrations (1.1 and 0.4 g L-1 ) were tested in outdoor pilot-scale flat-panel photobioreactors at semi-continuous cultivation mode. Fluorescence spectroscopy coupled with chemometric modeling was used to develop prediction models for fucoxanthin content and for biomass concentration to be applied for both microalgae species. Prediction models showed high R2 for cell concentration (0.93) and fucoxanthin content (0.77). Biomass productivity was lower for high biomass concentration than low biomass concentration, for both microalgae (1.1 g L-1 : 75.66 and 98.14 mg L-1 d-1 , for T. lutea and P. tricornutum, respectively; 0.4 g L-1 : 129.9 and 158.47 mg L-1 d-1 , T. lutea and P. tricornutum). The same trend was observed in fucoxanthin productivity (1.1 g L-1 : 1.14 and 1.41 mg L-1 d-1 , T. lutea and P. tricornutum; 0.4 g L-1 : 2.09 and 1.73 mg L-1 d- 1, T. lutea and P. tricornutum). These results show that biomass and fucoxanthin productivities can be set by controlling biomass concentration under outdoor conditions and can be predicted using fluorescence spectroscopy. This monitoring tool opens new possibilities for online process control and optimization. This article is protected by copyright. All rights reserved.