scholarly journals Variation in the fatty acid profiles of two cold water diatoms grown under different temperature, light, and nutrient regimes

2021 ◽  
Author(s):  
Kristian Spilling ◽  
Jukka Seppälä ◽  
Dagmar Schwenk ◽  
Heiko Rischer ◽  
Timo Tamminen
Keyword(s):  
Nutrient Limitation ◽  
Cold Water ◽  
Photosynthetic Apparatus ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Omega 3 Fatty Acids ◽  
Omega 3 ◽  
Wide Range ◽  
Different Temperatures

AbstractThere is a growing demand for marine omega-3 fatty acids (FAs) that is produced in high amounts by some microalgae. Here we determined the FA profiles of two cold water adapted diatoms, Chaetoceros wighamii and Thalassiosira baltica. The cultures were acclimated to different temperatures (3, 7, 11, 15, and 19 °C) and irradiance (20, 40, 130, and 450 μmol photons m−2 s−1) and the FA profiles were determined in exponential and stationary growth phases, the latter induced by different nutrient limitation (N, P, and Si). The maximum growth rate was obtained by both species at 11 °C, ≥ 130 μmol photons m−2 s−1 and was 0.8 day−1 and 0.6 day−1 for C. wighamii and T. baltica, respectively. Both species contained relatively high amounts of eicosapentaenoic acid (EPA). Thalassiosira baltica accumulated maximally ~ 30 mg EPA g−1 ash-free dry weight (AFDW) under Si-limitation. The content of docosahexaenoic acid (DHA) was lower, reaching up to 4 mg DHA g−1 AFDW in T. baltica. The concentration of EPA correlated positively with the chlorophyll a:carbon ratio, suggesting that it is bound to membranes in the photosynthetic apparatus and the EPA content in T. baltica was high enough to consider it as a potent candidate for cultivation under cold (< 15 °C) conditions. Covering a wide range of environmental conditions, the strongest differentiation in FA profiles was observed between the species with the growth phase/nutrient limitation pattern as the second most important driver of the FA composition.

scholarly journals Evaluation of Marine Synechococcus for an Algal Biorefinery in Arid Regions

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2233 ◽  
Author(s):  
Tomasz Bochenski ◽  
Tanmay Chaturvedi ◽  
Mette Hedegaard Thomsen ◽  
Jens Ejbye Schmidt
Keyword(s):  
Sodium Hydroxide ◽  
United Arab Emirates ◽  
Biomass Concentration ◽  
Local Strain ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Cell Disruption ◽  
Arid Environments ◽  
Wide Range

Implementing microalgae biorefinery in arid environments requires utilization of strains that can grow at high temperatures (above 28 °C) and salinity levels (above 30 ppt). In this study, we investigate the newly isolated seawater strain, Synechococcus, native to the United Arab Emirates, and evaluate its value as a perspective organism for cultivation (for fuel and bio-products) in regions with freshwater scarcity. The strain displayed tolerance to a wide range of temperature (22–37 °C) and salinity (20–41 ppt), with maximum biomass concentration of 0.72 g L−1 and a maximum growth rate of 82 mg L−1 d−1 at 25 °C and 33 ppt salinity. Lipids accumulation reached up to 26% of dry weight in nitrogen-depleted conditions (with 1.8 mM of nitrates addition to the media), whereas protein content exceeded 50% dry weight. In this study, harvesting is investigated using three chemical agents: Ferric chloride, sodium hydroxide, and chitosan. Cell disruption is analyzed for four distinct treatments: Enzymatic, alkaline, ultrasonic, and hydrothermal. Among tested methods, flocculation with sodium hydroxide and ultrasonication were found to be the most efficient techniques for harvesting and cell disruption, respectively. The growth characteristics of the local strain and the potential to derive protein and lipids from it makes it a promising biomass in a biorefinery context.

Field Determination of the Critical Nutrient Concentrations for Cladophora in Streams

1976 ◽  
Vol 33 (1) ◽  
pp. 85-92 ◽  
Author(s):  
S. L. Wong ◽  
B. Clark
Keyword(s):  
Plant Tissue ◽  
Stream Water ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Nutrient Concentrations ◽  
P Concentration ◽  
P Content ◽  
Waste Load ◽  
Total P

Many streams in southern Ontario experience excessive seasonal growth of aquatic plants such as Cladophora and Potamogeton. A direct relation, with a regression coefficient of 0.87, was observed between ambient P concentration in the water and P content of plant tissue in six rivers. Critical or growth controlling total P concentration of 60 μg/liter in stream water and 1.6 mg/gram dry weight in plant tissue were determined. Unlike P, no significant correlation was observed between N content of plant tissue and N concentration in water. The correlation of total P with plant growth can be used to estimate the waste load which would result in maximum growth rate of Cladophora.

Growth Rates and Nitrogen and Carbohydrate Contents of Juvenile Clams, Saxidomus giganteus, Fed Three Species of Algae

1973 ◽  
Vol 30 (12) ◽  
pp. 1825-1830 ◽  
Author(s):  
P. R. Walne
Keyword(s):  
Isochrysis Galbana ◽  
Live Weight ◽  
Dry Weight ◽  
Maximum Growth ◽  
Condition Index ◽  
Maximum Growth Rate ◽  
Experimental Conditions ◽  
Total Dry Weight ◽  
Tetraselmis Chui ◽  
Saxidomus Giganteus

Estimates were made of the increase in live and dry weights and in the content of ash, organic matter, carbohydrate (as glucose), and nitrogen when juveniles of the clam Saxidomus giganteus were fed for 21 days at various concentrations of Tetraselmis chui, Isochrysis galbana, and Phaeodactylum tricornutum. The condition index (organic weight as a percent of total dry weight) increased in all the experimental conditions with a mixture of I. galbana and T. chui, yielding a significantly higher index than either species on its own. The relative gain in glucose was greater than the increase in live weight or in nitrogen. The increase in live weight was such that the nigrogen content was approximately constant at 6–7 μgN/mg live weight irrespective of the feeding conditions. The N:glucose ratio decreased with increasing concentrations of I. galbana and P. tricornutum, and at the higher concentrations, where the maximum growth rate of clams occurred, the ratios were lower than in any of the clams fed on T. chui.

scholarly journals Establishment of Oxidative d-Xylose Metabolism in Pseudomonas putida S12

2009 ◽  
Vol 75 (9) ◽  
pp. 2784-2791 ◽  
Author(s):  
Jean-Paul Meijnen ◽  
Johannes H. de Winde ◽  
Harald J. Ruijssenaars
Keyword(s):  
Pseudomonas Putida ◽  
Caulobacter Crescentus ◽  
Glucose Dehydrogenase ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Xylose Utilization ◽  
Catabolic Pathway ◽  
Xylose Metabolism ◽  
Semialdehyde Dehydrogenase

ABSTRACT The oxidative d-xylose catabolic pathway of Caulobacter crescentus, encoded by the xylXABCD operon, was expressed in the gram-negative bacterium Pseudomonas putida S12. This engineered transformant strain was able to grow on d-xylose as a sole carbon source with a biomass yield of 53% (based on g [dry weight] g d-xylose−1) and a maximum growth rate of 0.21 h−1. Remarkably, most of the genes of the xylXABCD operon appeared to be dispensable for growth on d-xylose. Only the xylD gene, encoding d-xylonate dehydratase, proved to be essential for establishing an oxidative d-xylose catabolic pathway in P. putida S12. The growth performance on d-xylose was, however, greatly improved by coexpression of xylXA, encoding 2-keto-3-deoxy-d-xylonate dehydratase and α-ketoglutaric semialdehyde dehydrogenase, respectively. The endogenous periplasmic glucose dehydrogenase (Gcd) of P. putida S12 was found to play a key role in efficient oxidative d-xylose utilization. Gcd activity not only contributes to d-xylose oxidation but also prevents the intracellular accumulation of toxic catabolic intermediates which delays or even eliminates growth on d-xylose.

scholarly journals Effects of index selection on the performance and carcass composition of sheep given foods of different protein concentrationsad libitum

2004 ◽  
Vol 78 (2) ◽  
pp. 203-212 ◽  
Author(s):  
R. M. Lewis ◽  
G. C. Emmans ◽  
G. Simm
Keyword(s):  
Growth Rate ◽  
Dietary Protein ◽  
Protein Concentration ◽  
Live Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Carcass Composition ◽  
Control Line ◽  
Wide Range ◽  
Males And Females

AbstractSheep of a line selected on an index to increase carcass lean content at 150 days of age (selected (S); no. = 90), and an unselected control line (control (C); no. = 90), were given ad libitum foods of three different protein concentrations (192, 141 and 120 g/kg dry matter). Growth was measured from about 21 to 114 kg live weight. The carcasses of each line were analysed for lean, fat and bone at three widely varying weights in both males and females. Level of protein did not affect the extent to which S was superior to C in the content of fat (0.86 as much) or lean (1.08 as much) in the carcass. The fat concentration of the carcass increased, and the lean concentration decreased, as dietary protein concentration was reduced (P < 0.01). On the highest level of protein used, the S line grew 1.17 times as fast and was 1.10 times as efficient compared with C. The extent to which growth rate in S exceeded that in C was greater on the highest level of protein used (92.3 g/day) than on the two lower protein diets (26.4 g/day). The difference of 65.9 (s.e. 18.4) g/day was significant (P < 0.01). On the diet of highest protein concentration, growth was well described by a Gompertz function. The S line had an estimated maximum growth rate 1.25 times that of the C when averaged across males and females. A Spillman function was used to describe weight in terms of cumulative intake. It worked well for all three levels of dietary protein concentration. S sheep performed better than unselected sheep on foods differing in protein concentration and over a wide range of live weights, suggesting benefits are likely within the diverse farming environments found in practice.

Growth of a Methane-Utilizing Mixed Culture HD6T on Methanol and Poly-β-Hydroxybutyrate Biosynthesis

2010 ◽  
Vol 160-162 ◽  
pp. 171-175 ◽  
Author(s):  
Jing Dong ◽  
Jia Ying Xin ◽  
Ying Xin Zhang ◽  
Lin Lin Chen ◽  
Hong Ye Liang ◽  
...  
Keyword(s):  
Mixed Culture ◽  
Mineral Salt Medium ◽  
Biomass Concentration ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Production Costs ◽  
Lag Phase ◽  
Phase Duration ◽  
Phb Production

Methane-utilizing mixed culture HD6T was successfully cultivated in a brief non-sterile process using methanol as a sole carbon and energy source for the production of poly-β-hydroxybutyrate(PHB). Shake-flask experiments showed HD6T could grow well in the mineral salt medium with the addition of methanol exposed to the air directly. This non-sterile process and the use of cheap substrates (methanol) can reduce the production costs of PHB. It was found that HD6T grew better and PHB production in a more effective way with an initial liquid methanol concentration of 0.15%(v/v).The lag phase duration, the maximum growth rate, the biomass concentration and the PHB yield, for the optimal conditions were, respectively, 12.03h, 0.04h-1(OD600), 1.54g/l(dry weight), 0.424g/l(dry weight). Methane-utilizing mixed culture HD6T appears to be a promising organism for PHB production.

Growth kinetics of Marquis wheat. II. Carbon dioxide dependence

1972 ◽  
Vol 50 (4) ◽  
pp. 883-889 ◽  
Author(s):  
F. D. H. Macdowall
Keyword(s):  
Carbon Dioxide ◽  
Light Intensity ◽  
Carbon Dioxide Concentration ◽  
Dry Weight ◽  
Maximum Growth ◽  
Carbon Dioxide Enrichment ◽  
Low Light ◽  
Growth Coefficient ◽  
Light Intensities ◽  
Wide Range

Marquis wheat was grown in growth rooms with four different concentrations of carbon dioxide and four to seven different intensities of light in a 16-h photoperiod at 25 °C. Growth was expressed quantitatively as the pseudo-first-order rate coefficient. Carbon dioxide stimulated growth, but the effect was greater the lower the light intensity in opposition to the known effect on photosynthesis. Carbon dioxide and light, in effect, did not influence the "rate" of growth of wheat additively but, rather, mutually compensated over a wide range. The growth coefficient of the roots was a little less than that of the shoots at all carbon dioxide concentrations and light intensities, probably owing to the cost of translocation. However, root growth benefited most from carbon dioxide enrichment at low light intensities. At intermediate light intensity there appeared to be a carbon dioxide concentration optimal for shoot growth. Carbon dioxide enrichment did not influence the maximum growth coefficient of Marquis wheat with respect to light intensity. The light-using efficiency of growth, calculated for vanishingly low light intensity at which it is maximal, was maximal for shoots at 1300 ppm CO2 but that for laminal area and root dry weight increased with CO2 to 2200 ppm at which the value for "leaves" was nearly fourfold that for roots. Unlike photosynthesis, the stimulation of growth by raised CO2 concentration was accomplished by increased efficiency of, and not capacity for, the net photosynthetic use of light.

Dynamics of Exploited Whitefish Populations and their Management with Special Reference to the Northwest Territories

1975 ◽  
Vol 32 (3) ◽  
pp. 427-448 ◽  
Author(s):  
M. C. Healey
Keyword(s):  
Growth Rate ◽  
Population Size ◽  
Total Mortality ◽  
High Growth ◽  
Maximum Growth ◽  
High Growth Rate ◽  
Maximum Growth Rate ◽  
Stock Size ◽  
Slow Growth Rate ◽  
Wide Range

Available data on mortality, growth, reproduction, and stock size in exploited and unexploited populations of lake whitefish (Coregonus clupeaformis) are reviewed with a view to understanding the dynamics of exploited populations and improving their management. Natural mortality ranged from about 0.20 to 0.80 in unexploited populations. In exploited populations total mortality was as high as 0.94. Unexploited populations showed a wide range of growth rates. Growth rate increased with increasing exploitation, and growth rate in all heavily exploited populations was similar to the most rapid growth rate shown by unexploited stocks. Heavily exploited whitefish matured at a younger age and possibly also at a smaller size than those which were unexploited. Limited data on stock size suggest that although total population size declines under heavy exploitation, the vulnerable population remains of similar size.It is concluded that whitefish respond to fluctuations in population size through compensatory changes in growth rate, the difference between growth rate in a population and maximum growth rate is a measure of its scope for compensating for increased mortality. Populations with slow growth rate and low mortality should, therefore, have the best fishery potential, while those with high growth rate and high mortality have a low fishery potential. Further, it is possible to judge the fishery potential of a population or its stage of exploitation from relatively simple measurements of mortality, growth, age structure, and maturity.

Instability of a two-dimensional compressible jet

1970 ◽  
Vol 42 (1) ◽  
pp. 151-159 ◽  
Author(s):  
C. H. Berman ◽  
J. E. Ffowcs Williams
Keyword(s):  
Broad Band ◽  
Supersonic Jet ◽  
Nonlinear Effects ◽  
Maximum Growth ◽  
Vortex Sheet ◽  
High Gain ◽  
Maximum Growth Rate ◽  
Two Dimensional ◽  
Mean Flow ◽  
Wide Range

A linearized analysis of the two-dimensional double vortex sheet model of a jet shows that inviscid jet instabilities occur over a wide range of frequencies at all jet Mach numbers. No particular frequency for maximum growth rate exists unless finite shear layer thickness effects are considered. It is suggested that the model describes the essential characteristics of a real jet disturbed by long wavelength perturbations. The idea is advanced that the jet flow constitutes a broad band amplifier of high gain. Disturbances can grow rapidly to a size when nonlinear effects bring about significant interaction with the mean flow. By seeding the jet with disturbances of a type that are highly amplified it is argued that gross features of the flow may be affected and that the jet may be rendered less noisy at high Mach number. It is argued that some of these ideas are supported by the observation that a supersonic jet diffuses at an unusually rapid rate when subject to the oscillatory condition known as ‘screech’.

scholarly journals Effect of Salinity Difference on Lipid Content from Chaetoceros muelleri on Continuous Reactors

2019 ◽  
Vol 7 (1) ◽  
pp. 3-10
Author(s):  
Arif Rahmadi ◽  
Yeni Mulyani ◽  
Muhammad Wahyudin Lewaru
Keyword(s):  
Lipid Content ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Salinity Treatment ◽  
Chaetoceros Muelleri ◽  
Marine Microbiology ◽  
Randomized Design ◽  
Total Dry Weight ◽  
Salinity Difference

Chaetoceros muelleri is a microalgae class of Bacillariophyta (diatom) which is generally only used as feeds for fishes and shellfish larvae. Nevertheless, the biochemical content of this species is quite high and has the potential to be developed. This research aims to explain the effect of different salinity on the growth and lipid content of Chaetoceros muelleri cultured in a continuous photobioreactor. This research was carried out in August 2018 - February 2019. The research was conducted at the Laboratory of Marine Microbiology and the Laboratory of Bioprocess and Bioprospection of Natural Materials, Faculty of Fisheries and Marine Sciences, Padjadjaran University. The samples of Chaetoceros muelleri isolates were obtained from the Jepara Brackish Water Aquaculture Center. The methods used for the study was a ‘Completely Randomized Design’ (CRD) with four treatments. The salinity used is 15, 25, 35 and 45 ppt. The main parameters observed were growth and lipid content, while the supporting parameters were temperature, and pH. The results of this study showed that the highest lipid content was a salinity treatment of 35 ppt with a value of 25.37% of total dry weight obtained at the end of the culture. Based on growth, the highest density occurred in 25 ppt salinity with a maximum density of 3.80 ± 0.49 x 106 cells. ml-1 and maximum growth rate of 0.36 ± 0.008 div. day-1

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