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

Fengzheng Gao,Maria J Barbosa,Marta Sá,Iago Teles (Cabanelas, Itd),René H Wijffels

doi:10.1002/bit.27657

Fengzheng Gao, Maria J Barbosa + Show 3 more

Open Access

https://doi.org/10.1002/bit.27657

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Abstract

The effect of light on biomass and fucoxanthin (Fx) 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 Fx content and for biomass concentration to be applied for both microalgae species. Prediction models showed high R 2 for cell concentration (.93) and Fx content (.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 Fx 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 Fx 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.

Highlights

Fucoxanthin (Fx) is the main carotenoid in marine brown algae, playing a key role in photosynthesis (Miyashita et al, 2011; Wang et al, 2019)
It is reported in literature that T. lutea can accumulate up to 1.82% DW of Fx (Kim et al, 2012b; Mohamadnia et al, 2020), while P. tricornutum can accumulate as much as 5.92% DW (McClure et al, 2018)
Due to the high biomass concentration, no light was detected on the back of the flat‐panel PBRs

Summary

| INTRODUCTION

Fucoxanthin (Fx) is the main carotenoid in marine brown algae, playing a key role in photosynthesis (Miyashita et al, 2011; Wang et al, 2019). It is reported in literature that T. lutea can accumulate up to 1.82% DW of Fx (Kim et al, 2012b; Mohamadnia et al, 2020), while P. tricornutum can accumulate as much as 5.92% DW (McClure et al, 2018) Both microalgae are promising candidates for Fx production at industrial scale. This study intends to fill that gap, by investigating the effect of different incident light intensities on biomass and Fx productivity in T. lutea and P. tricornutum. T. lutea and P. tricornutum were cultivated in pilot‐scale outdoors flat‐panel photobioreactors (PBRs), at different cell concentrations, to evaluate the effect of specific light intensity on biomass and Fx productivities. This work provides a new approach to monitor microalgal growth and composition using online fluorescence

| MATERIAL AND METHODS

| RESULTS AND DISCUSSION

| CONCLUSIONS