Renewal rate and nutrient concentration as tools to modify productivity and biochemical composition of cyclostat cultures of the marine microalga Dunaliella tertiolecta

1995 ◽  
Vol 44 (3-4) ◽  
pp. 287-292 ◽  
Author(s):  
J. Fábregas ◽  
M. Patiño ◽  
B. O. Arredondo-Vega ◽  
J. L. Tobar ◽  
A. Otero
Keyword(s):  
Biochemical Composition ◽  
Nutrient Concentration ◽  
Dunaliella Tertiolecta ◽  
Renewal Rate ◽  
Marine Microalga

Distinctive control of metabolic pathways byChlorella autotrophicain semicontinuous culture

1996 ◽  
Vol 42 (11) ◽  
pp. 1087-1090 ◽  
Author(s):  
Jaime Fábregas ◽  
Manuel Patiño ◽  
Ever D. Morales ◽  
Adolfo Dominguez ◽  
Ana Otero
Keyword(s):  
Growth Rate ◽  
Metabolic Pathways ◽  
Biochemical Composition ◽  
Nutrient Concentration ◽  
Nutrient Concentrations ◽  
Organic Fraction ◽  
Culture Volume ◽  
Semicontinuous Culture ◽  
Marine Microalga ◽  
Strong Control

The marine microalga Chlorella autotrophica was cultured semicontinuously under light–dark synchronizing conditions at two nutrient concentrations (2 and 4 mmol N∙L−1) and five rates of daily renewal (from 10 to 50% of culture volume). Under such conditions, the biochemical composition of C. autotrophica was strongly influenced by the renewal rate, but unlike other marine microalgae, the nutrient concentration had no effect on the biochemical composition of the organic fraction of the microalga at a given growth rate. Results suggest that this species exerts a strong control over metabolic pathways, independent of the nutrient concentration in the medium.Key words: Chlorella autotrophica, semicontinuous culture, biochemical composition.

Response of the Marine Microalga Dunaliella tertiolecta to Nutrient Concentration and Salinity Variations in Batch Cultures

1986 ◽  
Vol 125 (5) ◽  
pp. 475-484 ◽  
Author(s):  
Jaime Fabregas ◽  
Concepcion Herrero ◽  
Buenaventura Cabezas ◽  
Rosa Liaño ◽  
Julio Abalde
Keyword(s):  
Nutrient Concentration ◽  
Dunaliella Tertiolecta ◽  
Batch Cultures ◽  
Marine Microalga ◽  
Salinity Variations

Modulation of photosynthesis and inorganic carbon acquisition in a marine microalga by nitrogen, iron, and light availability

2005 ◽  
Vol 83 (7) ◽  
pp. 917-928 ◽  
Author(s):  
Erica B Young ◽  
John Beardall
Keyword(s):  
Inorganic Carbon ◽  
Dunaliella Tertiolecta ◽  
Initial Slope ◽  
Carbon Concentrating Mechanism ◽  
High Affinity ◽  
N Limitation ◽  
Marine Microalga ◽  
Concentrating Mechanism ◽  
Energy Limitation ◽  
Use Efficiency

The marine microalga Dunaliella tertiolecta Butcher expresses a high affinity for dissolved inorganic carbon (DIC) through a carbon-concentrating mechanism (CCM), known to be influenced by CO2 availability and instantaneous light supply. However, the regulation by light and nutrient supply during growth is less understood, although N and Fe limitation impose an energy limitation by compromising the photosynthetic apparatus. Dunaliella tertiolecta was grown under steady-state conditions of limited light, N, and Fe availability, and the affinity for DIC was measured under saturating light. High affinity DIC uptake capacity was maintained by D. tertiolecta under all growth-limiting conditions, but was modulated in response to the limiting resource. Affinity of photosynthesis for DIC(k0.5) was significantly reduced in cells grown under low light, both in turbidostats and in batch culture (p ≤ 0.03), although cell-normalized Pmax was not significantly affected. In contrast, N and Fe limitation resulted in a significant reduction in cell chlorophyll, Pmax, and maximum photosystem II quantum yield (Fv/Fm), but the affinity for DIC was enhanced with increasing N or Fe stress. While the affinity for DIC improved with increasing N stress (k0.5 < 17.8 µM at µ = 0.27 d–1 versus k0.5 > 26 µM at µ ≥ 0.77 d–1), light use efficiency (α) was impaired under N limitation, suggesting a trade-off between light harvesting capacity and active DIC uptake. Stable C isotope analysis of Fe-limited cells confirmed a lower fractionation by the most Fe-limited cells, consistent with the k0.5 data and more active DIC acquisition (δ13C = –19.56 at µ = 0.27 d–1 cf. δ13C = –26.28 at µ = 0.77 d–1). Assessment of affinity for DIC using k0.5 was supported by the close fit of P versus DIC curves to Michaelis–Menten kinetics; with the high DIC affinity of D. tertiolecta, there was poor resolution in the initial slope of the P versus DIC curve as a parameter of affinity for DIC. Enhanced DIC uptake efficiency under Fe and N limitation may relate to improved resource-use efficiency conferred by CCM activity.Key words: algae, carbon-concentrating mechanism, iron, light, nitrogen, nutrient limitation, photosynthesis.

scholarly journals Decrease of plasma cholesterol with the marine microalga Dunaliella tertiolecta in hyper cholesterolemic rats.

1994 ◽  
Vol 40 (6) ◽  
pp. 533-540 ◽  
Author(s):  
JAIME FÁBREGAS ◽  
CONCEPCIÓN HERRERO ◽  
YOLANDA GAMALLO ◽  
ANA OTERO ◽  
JOSÉ MANUEL PAZ ◽  
...  
Keyword(s):  
Plasma Cholesterol ◽  
Dunaliella Tertiolecta ◽  
Marine Microalga
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