Optimizing fucoxanthin production in the diatom Phaeodactylum tricornutum using ARTP-evolved mutant consortia and a multifaceted approach in LED-driven photobioreactors

Abstract

The diatom Phaeodactylum tricornutum is known for its rapid growth and high fucoxanthin content (1–3% of dry weight), a photosynthetic pigment with considerable pharmaceutical and nutraceutical potential. Despite these advantages, the commercial biotechnological applications of this organism have not yet been realized, primarily due to challenges in scaling up photobioreactor (PBR) systems, as well as issues with the organism’s robustness and production processes. In this study, we present a multifaceted approach to enhance fucoxanthin productivity by combining innovations in PBR design, strain improvement, and LED light recipes. Systematic evaluation of P. tricornutum in 700 mL column PBRs identified optimal light conditions (e.g., 660 nm red light at 50 μmol photons m–2 s−1 with optimized light regimes), which were subsequently scaled up to novel 200 L and 10,000 L PBRs. Meanwhile, atmospheric and room temperature plasma mutagenesis, coupled with an adaptive evolution screening technique, generated superior mutant consortia exhibiting enhanced phenotypic characteristics, including higher fucoxanthin yield and long-term stability of cultivation. Comparative cultivation experiments in the 10,000 L PBR demonstrated the superiority of the mutant consortia, yielding 0.59 g L–1 biomass (an 18% increase) and 7.29 mg L–1 fucoxanthin (a 32.79% increase) compared to the wild type strain. Productivity was significantly improved, with biomass and fucoxanthin production rates reaching 0.12 g L–1 d–1 (a 33.33% increase) and 1.47 mg L–1 d–1 (a 54.74% increase) in the 10,000 L PBR, respectively. This work provides an optimized light recipe, superior mutant consortia, and scalable PBR design, effectively bridging laboratory-scale research with industrial application potential.

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