| Title | Growth and photosynthetic performance of Chlamydopodium fusiforme cells cultivated in BG11 and Bristol media |
| Abstract | Nitrogen is an essential nutrient for all life forms and its availability is periodically limited in marine and freshwater ecosystems. To optimize the growth of the freshwater microalga Chlamydopodium fusiforme and to investigate the cell acclimation process to different amounts of nitrogen, we grew cells in Bristol and BG11, under fixed conditions of 10 h:14 h light/dark cycle. Cultures grown in BG11 exhibited higher biomass accumulation, reaching a cell dry weight of 1.94 ± 0.1 g L-1, while in Bristol it reached 1.58 ± 0.1 g L-1. In cells grown in BG11, chlorophyll content increased continuously up to 79.6 mg L-1 (9th day), while in Bristol it was much lower (29.5 mg L-1). This fact caused a strong difference in their spectrally averaged optical cross-section normalized to chlorophyll a (a*), and consequently in their photosynthetic performance (oxygen evolution and electron transport rates). Carotenoid content followed a similar pattern. It was interesting to note that despite this great difference in chlorophyll concentration, both photosynthesis rate and cell dry weight were not affected proportionally. The chlorophyll a fluorescence measurements indicated a stable effective quantum yield of photosystem II in both culture conditions. During the dark phase of the cycle we observed in both cultures a remarkable reduction of both electron transfer and photosynthesis rates, while maximum quantum yield of PSII remained stable (0.74 ± 0.01). This indicated that the reduction in both photosynthesis rate and maximum electron transport rate (ETRmax) observed during the dark phase were not due to damage of PSII reaction centers but rather to reduced flow of electron subsequent to PSII. Recovery of the fully photosynthetic capacity required about 1 h of illumination |
| Source | Journal of applied phycology 32 (1), pp. 145–152 |
| Keywords | Chlamydopodium fusiforme.Chlorophyceae.Microalgae.Variable fluorescence.Photosynthesis.Biomasscomposition |
| Journal | Journal of applied phycology |
| Editor | Kluwer Academic Publishers, Dordrecht, Paesi Bassi |
| Year | 2020 |
| Type | Articolo in rivista |
| DOI | 10.1007/s10811-019-01900-y |
| Authors | Touloupakis E., Tartari G., Zittelli, G.C., Torzillo, G. |
| Text | 452315 2020 10.1007/s10811 019 01900 y Scopus 2 s2.0 85073943820 Scopus 000521187500013 Chlamydopodium fusiforme.Chlorophyceae.Microalgae.Variable fluorescence.Photosynthesis.Biomasscomposition Growth and photosynthetic performance of Chlamydopodium fusiforme cells cultivated in BG11 and Bristol media Touloupakis E., Tartari G., Zittelli, G.C., Torzillo, G. CNR Istituto di Ricerca sugli Ecosistemi Terrestri, Via Madonna del Piano 10, Sesto Fiorentino, Florence, I 50019, Italy CNR Istituto di Ricerca sulle Acque, Largo Tonolli 50, Verbania, 28922, Italy CNR Istituto per la Bioeconomia, Via Madonna del Piano 10, Sesto Fiorentino, Florence, I 50019, Italy Nitrogen is an essential nutrient for all life forms and its availability is periodically limited in marine and freshwater ecosystems. To optimize the growth of the freshwater microalga Chlamydopodium fusiforme and to investigate the cell acclimation process to different amounts of nitrogen, we grew cells in Bristol and BG11, under fixed conditions of 10 h 14 h light/dark cycle. Cultures grown in BG11 exhibited higher biomass accumulation, reaching a cell dry weight of 1.94 ± 0.1 g L 1, while in Bristol it reached 1.58 ± 0.1 g L 1. In cells grown in BG11, chlorophyll content increased continuously up to 79.6 mg L 1 9th day , while in Bristol it was much lower 29.5 mg L 1 . This fact caused a strong difference in their spectrally averaged optical cross section normalized to chlorophyll a a , and consequently in their photosynthetic performance oxygen evolution and electron transport rates . Carotenoid content followed a similar pattern. It was interesting to note that despite this great difference in chlorophyll concentration, both photosynthesis rate and cell dry weight were not affected proportionally. The chlorophyll a fluorescence measurements indicated a stable effective quantum yield of photosystem II in both culture conditions. During the dark phase of the cycle we observed in both cultures a remarkable reduction of both electron transfer and photosynthesis rates, while maximum quantum yield of PSII remained stable 0.74 ± 0.01 . This indicated that the reduction in both photosynthesis rate and maximum electron transport rate ETRmax observed during the dark phase were not due to damage of PSII reaction centers but rather to reduced flow of electron subsequent to PSII. Recovery of the fully photosynthetic capacity required about 1 h of illumination 32 Published version https //doi.org/10.1007/s10811 019 01900 y 19/08/2019 2020 Growth_and_photosynthetic_performance_of_Chlamydop The aim of this work was to investigate the growth and the biochemical composition of the freshwater microalga Chlamydopodium fusiforme on two culture media Bristol and BG11, having different nitrogen and phosphorus concentrations. The microalga was grown in both growth media, under fixed conditions of light/dark cycle, light irradiance, and temperature. The experiments were carried out over the course of 10 days, and at the end cells were harvested in order to evaluate their biochemical composition. 2020 Growth_and_photosynthetic_performance_of_Chlamydop.pdf Articolo in rivista Kluwer Academic Publishers 0921 8971 Journal of applied phycology Journal of applied phycology J. appl. phycol. Journal of applied phycology. giuseppe.torzillo TORZILLO GIUSEPPE graziella.chinizittelli CHINI ZITTELLI GRAZIELLA eleftherios.touloupakis TOULOUPAKIS ELEFTHERIOS gabriele.tartari TARTARI GABRIELE |
