@article{Borovkov_Gudvilovich_Novikova_Klimova_2022, title={Production characteristics of Porphyridium purpureum (Bory) Drew et Ross semi-continuous culture at low irradiance}, volume={7}, url={https://marine-biology.ru/mbj/article/view/326}, DOI={10.21072/mbj.2022.07.1.01}, abstractNote={<p>The red microalga <em>Porphyridium purpureum</em> (Bory de Saint-Vincent, 1797) Drew et Ross, 1965 is of great interest to researchers as a source of various biologically valuable substances, with their content in cells being determined by cultivation conditions. Phycobiliproteins concentration in <em>P. purpureum</em> cells depends directly on nitrogen concentration in the culture medium and cell irradiance. Semi-continuous cultivation allows maintaining these parameters at a level given. The aim of the work was to study <em>P. purpureum</em> culture growth and B-phycoerythrin (B-PE) accumulation and production at low irradiance, with minimal rates of pigment photodestruction. <em>P. purpureum</em> semi-continuous (quasi-continuous) cultivation was carried out at a specific flow rate of 0.1 and 0.2 day<sup>−1</sup> and mean surface irradiance of 5 and 25 W·m<sup>−2</sup>. <em>P. purpureum</em> culture productivity increased by 1.6–17 times both with a rise in surface irradiance 5 to 25 W·m<sup>−2</sup> and an increase in the medium specific flow rate 0.1 to 0.2 day<sup>−1</sup>. Maximum productivity values for the experimental conditions (0.21 g·L<sup>−1</sup>·day<sup>−1</sup>) were recorded at 25 W·m<sup>−2</sup> and 20 % medium specific flow rate, but those were 1.5–2 times lower than the precalculated ones. In <em>P. purpureum</em> cells, protein and B-PE concentrations decreased both with an increase in surface irradiance (by 15–20 %) and with a rise in a specific flow rate (by 1.5 times) for all the variants. The shifts in protein and B-PE concentration in <em>P. purpureum</em> culture had a unidirectional character as well; those mainly corresponded to the shift in the culture density. <em>P. purpureum</em> B-PE productivity increased by 1.5–1.9 times with a rise in surface irradiance 5 to 25 W·m<sup>−2</sup>. Maximum B-PE productivity (13 mg·L<sup>−1</sup>·day<sup>−1</sup>) was recorded for the variants of the experiment with a surface irradiance of 25 W·m<sup>−2</sup> (0.1 and 0.2 day<sup>−1</sup>). An increase in specific irradiance of <em>P. purpureum</em> cells 7 to 26 W·g<sup>−1</sup> resulted in a rise in biomass productivity by 2.6 times; in B-PE productivity, by 1.8 times; and in protein productivity, by 1.7 times. In the experiment, irradiance was the factor determining the production characteristics of <em>P. purpureum</em> culture, and it was confirmed by the data obtained.</p>}, number={1}, journal={Marine Biological Journal}, author={Borovkov, A. B. and Gudvilovich, I. N. and Novikova, T. M. and Klimova, E. V.}, year={2022}, month={Mar.}, pages={3–13} }