Potential for the production of carotenoids of interest in the polar diatom Fragilariopsis cylindrus

Carotenoid xanthophyll pigments are receiving growing interest in various industrial fields due to their broad and diverse bioactive and health beneficial properties. Fucoxanthin (Fx) and the inter-convertible couple diadinoxanthin–diatoxanthin (Ddx+Dtx) are acknowledged as some of the most promising xanthophylls; they are mainly synthesized by diatoms (Bacillariophyta). While temperate strains of diatoms have been widely investigated, recent years showed a growing interest in using polar strains, which are better adapted to the natural growth conditions of Nordic countries. The aim of the present study was to explore the potential of the polar diatom Fragilariopsis cylindrus in producing Fx and Ddx+Dtx by means of the manipulation of the growth light climate (daylength, light intensity and spectrum) and temperature. We further compared its best capacity to the strongest xanthophyll production levels reported for temperate counterparts grown under comparable conditions. In our hands, th..., , , # Potential for the Production of Carotenoids of Interest in the Polar Diatom Fragilariopsis cylindrus

[https://doi.org/10.5061/dryad.v6wwpzh4j](https://doi.org/10.5061/dryad.v6wwpzh4j)

The polar diatoms Fragilariopsis cylindrus (CCMP3323) cultures were grown in sterilize natural sea water enriches with f or f/2 medium , at 0 °C and 7 °C under different photoperiods (12h light : 12h dark, 18h light : 6h dark, and continuous light), light intensities (5.8, 11.7, 23.4 µmol photons m−2 s−1 of photosynthetically usable radiation)  and 3 light spectra (artificial ‘white’ light spectrum, monochromatique blue 445nm and red light 660nm). Importantly, and contrary to many studies conducted in the field, cultures were kept optically thin, in order to control the light field inside the reactors, by a daily dilution with fresh f/2 medium (semi-continuous cultivation) to maintain a cell concentration of 1 millions cells mL−1. The so-called ‘white’ light spectrum used here was built to be as close...