Fucoxanthin production from Tisochrysis lutea and Phaeodactylum tricornutum at industrial scale

Fucoxanthin is a xanthophyll carotenoid with high market value. Currently, seaweeds are the primary source for fucoxanthin industrial production. However, marine microalgae reach 5 to 10 times higher concentrations (2.24 to 26.6 mg g-1 DW) and are considered a promising feedstock. In this work, two marine microalgae were produced at industrial scale to evaluate biomass and fucoxanthin production: Phaeodactylum tricornutum for autumn/winter and Tisochrysis lutea for spring/summer. Both strains were grown in 15 m3 tubular flow-through photobioreactors; for 170 consecutive days of semi-continuous cultivation regime. The average volumetric biomass productivities of P. tricornutum and T. lutea were 0.11 and 0.09 g DW L-1 day-1. P. tricornutum reached higher maximum biomass concentration (2.87 g DW L-1) than T. lutea (1.47 g DW L-1). P. tricornutum fucoxanthin content ranged between 0.2 and 0.7% DW, while T. lutea between 0.2 and 0.6% DW. The fucoxanthin content was correlated with the irradiation (MJ m-2) and biomass concentration in the photobioreactor (g L-1). This is the first work in literature reporting a long-term industrial production of T. lutea. Overall, we showed possible scenarios for fucoxanthin production from microalgae, increasing the window to supply the industry with steady production throughout the year.info:eu-repo/semantics/publishedVersio

Distribution and Abundance of MAAs in 33 Species of Microalgae across 13 Classes

We provide a direct comparison of the distribution and abundance of mycosporine-like amino acids (MAAs) in a diverse range of microalgal cultures (33 species across 13 classes) grown without supplementary ultraviolet radiation (UV). We compare the MAAs in cultures with those present in characterised natural phytoplankton populations from the English Channel. We detected 25 UV absorbing compounds including at least two with multiple absorption maxima. We used LC-MS to provide chemical characterisation of the six most commonly occurring MAAs, namely, palythene, palythine, mycosporine-glycine, palythenic acid, porphyra-334 and shinorine. MAAs were abundant (up to 7 pg MAA cell−1) in 10 species, with more minor and often unknown MAAs in a further 11 cultures. Shinorine was the most frequently occurring and abundant MAA (up to 6.5 pg cell−1) and was present in all but two of the MAA-containing species. The study provides further insight into the diversity and abundance of MAAs important from an ecological perspective and as potential source of natural alternatives to synthetic sunscreens

Morphology, growth, photosynthesis and pigments in Laminaria ochroleuca (Laminariales, Phaeophyta) under UV radiation

Young sporophytes of Laminaria ochroleuca were exposed in the laboratory either to a full light spectrum or to light depleted of only ultraviolet-B radiation (UVB) or of the whole ultraviolet radiation (UVR) using cutoff glass filters. The plants were grown under 16:8 h light-dark cycles with 6 h additional UV exposure in the middle of the light phase. Effective quantum yield of photosystem II (ΔF/Fm′) was measured daily, 1 h before UV exposure, at 2 and 5 h cumulative UV exposure and at 1 and 4 h after UV exposure. Growth was measured using two methods in separate experiments. In the first, a scanner with image analysis software was used to measure surface area every 3 days for 4 weeks. In the second, a growth chamber with online video measuring technique was used to measure growth every 10 min for 2 weeks. Pigments were measured at the end of the experiments. During the first day of UV exposure, the photosynthetic yield of plants exposed to photosynthetically active radiation (PAR) + ultraviolet-A radiation (UVA) and PAR + UVA + UVB was significantly reduced but was able to recover 1 h after the end of UV exposure. An increasing mean ΔF/Fm′ during UV exposure showed partial acclimation of photosynthesis in young sporophytes in the course of several days. However, a higher growth rate was observed in plants exposed to PAR alone, whereas reduced growth and damaged tissue were observed in plants exposed to UVR. Similarly, a lower content of all pigments was measured in thalli exposed to PAR + UVR. The result shows that acclimation of photosynthesis could underestimate the negative effect of this stress factor. Growth, as an integrative process, is a better parameter to explain ecophysiological performance at organism level. It was shown that growth and morphology of young sporophytes of L. ochroleuca are susceptible to UV damage, which could effectively limit the upper distributional range of this species