Variations in the biochemical composition of the diatom Coscinodiscus eccentricus with culture age and salinity (original) (raw)
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Latin American Journal of Aquatic Research, 2012
The estuarine diatom Thalassiosira weissflogii (Fryxell & Hasle, 1977) has been widely used as live feed in aquaculture. The growth rate and biochemical composition of microalgae are highly influenced by environmental factors such as, light, salinity and nutrient availability. Salinity is difficult to control in some shrimp laboratories specialized in larvae production, because these laboratories depend upon the levels measured in estuaries or coastal lagoons, which are the water sources for larvae culture. The present study evaluated the effect of different salinities (25, 30, 35, 40, 45 and 50 psu), on the growth and chemical composition of T. weisflogii at three culture phases, under laboratory conditions. The highest growth rate and maximum cell density were found at 25 psu. Decrease in size and striking changes in morphology of the cells were observed at the higher salinities and drastic changes occurred at 50 psu. Protein and carbohydrate content were higher at low salinities (25 and 30 psu) during the stationary phase. The lipid production was higher at low salinities, but diminished as the phase changes occurred; in contrast, the lipid content was unaffected by the growth phase at higher salinities (≥35 psu). The higher growth rate and better biochemical composition were obtained at 25 and 30 psu.
Latin American Journal of Aquatic Research, 2012
The estuarine diatom Thalassiosira weissflogii (Fryxell & Hasle, 1977) has been widely used as live feed in aquaculture. The growth rate and biochemical composition of microalgae are highly influenced by environmental factors such as, light, salinity and nutrient availability. Salinity is difficult to control in some shrimp laboratories specialized in larvae production, because these laboratories depend upon the levels measured in estuaries or coastal lagoons, which are the water sources for larvae culture. The present study evaluated the effect of different salinities (25, 30, 35, 40, 45 and 50 psu), on the growth and chemical composition of T. weisflogii at three culture phases, under laboratory conditions. The highest growth rate and maximum cell density were found at 25 psu. Decrease in size and striking changes in morphology of the cells were observed at the higher salinities and drastic changes occurred at 50 psu. Protein and carbohydrate content were higher at low salinities (25 and 30 psu) during the stationary phase. The lipid production was higher at low salinities, but diminished as the phase changes occurred; in contrast, the lipid content was unaffected by the growth phase at higher salinities (≥35 psu). The higher growth rate and better biochemical composition were obtained at 25 and 30 psu.
Aquaculture, 2005
The marine diatom Chaetoceros cf. wighamii has been investigated for its potential use as food in mariculture. In this work, we investigated temperature (20, 25, and 30 8C), salinity (25 and 35) and carbon dioxide addition (air and air + CO 2) effects on growth and biochemical composition of C. cf. wighamii, under laboratory conditions. C. cf. wighamii growth and biomass was primarily affected by carbon dioxide addition and to a lesser extent by temperature and salinity. In general, lipid and carbohydrate content were higher at lower temperatures (20 and 25 8C) while protein was unaffected. Carbon dioxide addition increased protein and lowered carbohydrates, but had no effect on lipid content. Carbohydrates were enhanced while lipids and protein decreased at the highest salinity (35). These results should be taken into consideration when evaluating the nutritional value of this microalga for marine invertebrate larvae.
Marine Biology, 1976
Skeletonema costatum was grown in chemostats under ammonium or silicate limitation to examine its growth kinetics and changes in cellular chemical composition at different steady-state growth rates. When the relationship between the effluent limiting substrate concentration and steady-state growth rates was examined, deviations from the simple hyperbolic form of the Monod growth equation were noted at low and high dilution rates. The data from the plot of growth rate and substrate concentration were divided into 4 regions and the relationship of these regions to cell quota is discussed. Two physiological states were identified. All populations grown at m <0.05 h-I , regardless of the size of the cells or the magnitude of Q, exhibited a maximal growth rate of approximately 0.05 h-l, while populations grown at higher dilution rates (D >0.06 h-1 for silicate and >0.08 h-I for ammonium) were characterized by maximal growth rates of 0.12 h-I to 0.14 h-1. The maximal value of growth rate is obtained only in cultures grown at very high dilution rates where nutrient shift-up appears to occur, the cell quota approaches a maximum and the heterogeneous cell population becomes more homogeneous.
Biological Responses of the Marine Diatom Chaetoceros simplex Ostenfeld
Biological Responses of the Marine Diatom Chaetoceros simplex Ostenfeld, 2016
Chaetoceros simplex Ostenfeld of marine diatoms was isolated and purified from the sub-surface waters of the north-western part of the Red Sea, Egypt (Hurgada). The isolated grown cells are exposed to different concentrations of nitrate and phosphate to estimate their effects on the growth and some metabolic activities of the organism. In general, the results indicated that concentrations of 100 μM nitrate and 5μM p hosp hate stimulated the algal growth by 60% and 32 %, respectively in the 8th day of culture. While, the values of 300 μM nitrate and 50 μM p hosp hate exhibited a decrease in the algal growth by 44 % and 49 %, respectively as compared with the control culture. The photosynthetic pigments (Chl-a, Chl-c and Carotenoids), total soluble proteins and carbohydrates of Chaetoceros simplex followed a similar pattern of change to that of growth in response to different treatments of nitrate and phosphate. While, the addition of different treatments of nitrate and phosphate to F/2 medium decreased the total lipids of C. simplex. Statistical analysis of the data indicated that 5 μM p hosp hates and 50 μM nitrates were the highly significant and most effective concentrations that positively affect most of different metabolic activities of Chaetoceros simplex. Thus, Chaetoceros simplex culture could be used as larval feed or other purposes cultured using 50 μM nitrate and 5μM p hosp hate. Keywords Chaetoceros simplex; Nitrate; Phosphate; Metabolic activities
Acta Manilana, 2014
Diatoms are unicellular and colonial microalgae which are currently explored as one of the potential algal species for biofuel production since they are known to accumulate high lipid content under different environmental stresses. This paper focuses on the diatom Nitzschia palea subjected under various culture conditions of light intensity, temperature, and pH, using batch culture experiments for optimizing their growth, lipid content and lipid productivity. Nitzschia palea attained a maximum growth of 3.0810 6 cells/mL under the optimum conditions of 18 mmol photons m-2 s-1 light intensity, temperature of 30°C, and pH 9. The highest lipid content (1.23 mg mL-1) was attained at 30°C. Lipid productivity increases with increased light intensity, temperature and pH. This was positively correlated with both lipid content and culture conditions (p <0.05), while growth of N. palea was negatively correlated with lipid content (p <0.05). Nitzschia palea had shown a relatively high growth rate and lipid content which are important characteristics for consideration as a potential for biofuel resource.
Latin American Journal of Aquatic Research, 2012
The estuarine diatom Thalassiosira weissflogii (Fryxell & Hasle, 1977) has been widely used as live feed in aquaculture. The growth rate and biochemical composition of microalgae are highly influenced by environmental factors such as, light, salinity and nutrient availability. Salinity is difficult to control in some shrimp laboratories specialized in larvae production, because these laboratories depend upon the levels measured in estuaries or coastal lagoons, which are the water sources for larvae culture. The present study evaluated the effect of different salinities (25, 30, 35, 40, 45 and 50 psu), on the growth and chemical composition of T. weisflogii at three culture phases, under laboratory conditions. The highest growth rate and maximum cell density were found at 25 psu. Decrease in size and striking changes in morphology of the cells were observed at the higher salinities and drastic changes occurred at 50 psu. Protein and carbohydrate content were higher at low salinities (25 and 30 psu) during the stationary phase. The lipid production was higher at low salinities, but diminished as the phase changes occurred; in contrast, the lipid content was unaffected by the growth phase at higher salinities (≥35 psu). The higher growth rate and better biochemical composition were obtained at 25 and 30 psu.
Marine Ecology Progress Series, 1991
Production of intracellular and extracellular lipid classes by Chaetoceros gracilis was studied over a wide range of supply rates of inorganic phosphorus and silicon. The cage culture turbidostat, a continuous culture technique providing closely controlled nutrient concentrations and population densities, was used for growing the diatom. Nutrient, intracellular lipid and chlorophyll a analyses were performed over the whole range of nutrients used, but dissolved lipid production was measured only at the extremes of the ranges of nutrient concentrations. The production of triglycerides, a storage class of lipids, was triggered by nutrient stress with either phosphorus or silicon, as had earlier been demonstrated with nitrogen. The synthesis of phospholipids was reduced under phosphorus stress, while the synthesis of chlorophyll a was increased by silicon stress. The increase in chlorophyll a per cell under silicon stress brings into question the use of this pigment as a measure of biomass. Particulate lipid y e l d was highest in intermediate concentrations of both nutrients.
Iranian Journal of Fisheries Sciences, 2018
Introduction Microalgae grow in both seawater and freshwater (Carlsson et al., 2007). They have some similarities to terrestrial plants with different growth media and efficient access to water, carbon dioxide and other nutrients, but have higher growth rates and lipid content with high yield per unit area. There are several important applications of microalgae such as animal feed, playing a valuable role in cosmetics, biodiesel production and pharmaceuticals (Olaizola, 2003; Soares et al., 2006; Patil et al., 2008; Huang et al., 2010). In addition, they are more beneficial than corn, soybean and palm oil in biofuel production in the world (Chisti, 2007; Lora and Andrade, 2009; Mata et al., 2010). Most diatoms microalgae such as Chaetoceros calcitrans are cultivated in bioreactors and as a cosmetic and pharmaceutical than food production at the moment (Chisti, 2007; Janaun and Ellis, 2010). These diatoms with its high lipid content has some major pigments such as chlorophyll a, c1 a...