scholarly journals FEATURES OF SPIRULINA PLATENSIS CULTIVATED UNDER AUTOTROPHIC AND MIXOTROPHIC CONDITIONS

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Zahra Rasouli ◽  
Mahdi Parsa ◽  
Hossein Ahmadzadeh
Keyword(s):  
Spirulina Platensis ◽  
Cell Concentration ◽  
Biomass Productivity ◽  
Stability Index ◽  
Cell Number ◽  
Membrane Stability ◽  
Tolerance Index ◽  
Chlorophyll Protein ◽  
Maximum Cell ◽  
Maximum Cell Concentration

Cultivation of Spirulina platensis in Zarrouk media containing 0–20 g l-1 glucose was studied in a photobioreactor for 30 days using a light intensity of 3 klux. Various parameters were measured to evaluate the enhancement of cell performance with glucose such as cell number, osmolarity, membrane stability, biomass productivity, doubling time, stress intensity, stress tolerance, chlorophyll, protein, carbohydrates, and lipid contents. Based on the results, we concluded that S. platensis is able to grow and produce some ingredients in Zarrouk media containing up to 20 g l-1 of glucose which is the first to be reported. The cell concentration of the mixotrophic cultures (80 cells per mm2) corresponded well to the sum of the autotrophic cell concentrations (50 cells per mm2), showing that the addition of carbohydrate positively effects on the microalgae growth. The continuous operation supplemented with 0.5 g l-1 of glucose (G0.5) led to the maximum cell concentration about 9.06 g l-1 wet and 1.32 g l-1 dry weights. The highest tolerance index, specific growth rate, biomass productivity, cell division, osmolarity and membrane stability index were respectively 102.5%, 0.15 d-1, 0.04 g l-1d-1, 0.26 div d-1, 0.87 osmol kg-1 and 93.8%, obtained in the same treatment. Chlorophyll (6.7 % in G0; 0.046 g l-1 in G0.5), protein (79.9 % and 0.884 g l-1 in G0.5), carbohydrates (55.5% in G20; 0.492 g l-1 in G6) and lipid (53.3% in G10; 0.636 g l-1 in G0) percentages and yields were mostly enhanced in the mixotrophic condition. This study indicated that mixotrophic growth of S. platensis is useful for commercial biomass production.

scholarly journals The instability of gyrotactically trapped cell layers

2019 ◽  
Vol 868 ◽  
Author(s):  
Smitha Maretvadakethope ◽  
Eric E. Keaveny ◽  
Yongyun Hwang
Keyword(s):  
Cell Layer ◽  
Cell Concentration ◽  
Gravitational Instability ◽  
Plane Channel ◽  
Thin Layers ◽  
Relevant Parameter ◽  
Potential Mechanism ◽  
Cell Layers ◽  
Maximum Cell ◽  
Maximum Cell Concentration

Several metres below the coastal ocean surface there are areas of high ecological activity that contain thin layers of concentrated motile phytoplankton. Gyrotactic trapping has been proposed as a potential mechanism for layer formation of bottom-heavy swimming algae cells, especially in flows where the vorticity varies linearly with depth (Durham et al., Science, vol. 323(5917), 2009, pp. 1067–1070). Using a continuum model for dilute microswimmer suspensions, we report that an instability of a gyrotactically trapped cell layer can arise in a pressure-driven plane channel flow. The linear stability analysis reveals that the equilibrium cell-layer solution is hydrodynamically unstable due to negative microswimmer buoyancy (i.e. a gravitational instability) over a range of biologically relevant parameter values. The critical cell concentration for this instability is found to be $N_{c}\simeq 10^{4}~\text{cells}~\text{cm}^{-3}$, a value comparable to the typical maximum cell concentration observed in thin layers. This result indicates that the instability may be a potential mechanism for limiting the layer’s maximum cell concentration, especially in regions where turbulence is weak, and motivates the study of its nonlinear evolution, perhaps, in the presence of turbulence.

scholarly journals PRODUCTION OF DOCOSAHEXAENOIC ACID (DHA) FROM Thraustochytrium sp. ATCC 26185 USING DIFFERENTS NITROGEN CONCENTRATIONS

2014 ◽  
Vol 32 (1) ◽  
Author(s):  
VALCENIR JUNIOR MENDES FURLAN ◽  
MARIA DO CASTELO PAULO ◽  
VICTOR WEGNER MAUS ◽  
JULIA FERREIRA ◽  
IRINEU BATISTA ◽  
...  
Keyword(s):  
Cell Concentration ◽  
Batch Process ◽  
Fed Batch ◽  
The Third ◽  
Culture Time ◽  
Cell Biomass ◽  
Oleaginous Microorganism ◽  
Nitrogen Concentrations ◽  
Maximum Cell ◽  
Maximum Cell Concentration

In this work it was studied the polyunsaturated fatty acids (PUFAs) production, especially DHA, from Thraustochytrium sp. ATCC 26185, under different total nitrogen (TN) availability. Three different TN conditions were evaluated: two with initial concentrations of 2.4 g/L and 0.8 g/L, and the third in a fed-batch process with a rate of 0.009 g/L.h. For each experiment the biomass, glucose, TN and PUFAs were determined. The major composition of the PUFAs in Thraustochytrium sp. ATCC 26185 cell biomass were DPA ω6 (21-25 %) and DHA (69-73 %), regardless of the type and time of culture. The maximum cell concentration (30.2 g/L) was obtained using 2.4 g/L TN in 168 h of culture. With this same concentration of TN it was possible to produce the highest concentration of DHA (1.16 g/L) in 120 h of culture, demonstrating that the growth of Thraustochytrium sp. ATCC 26185 and yield of PUFAs are dependent on the source concentration of TN available for consumption of this oleaginous microorganism, as well as culture time.

Oxygen supply in disposable shake-flasks: prediction of oxygen transfer rate, oxygen saturation and maximum cell concentration during aerobic growth

2013 ◽  
Vol 35 (8) ◽  
pp. 1223-1230 ◽  
Author(s):  
Sarah Schiefelbein ◽  
Alexander Fröhlich ◽  
Gernot T. John ◽  
Falco Beutler ◽  
Christoph Wittmann ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Supply ◽  
Cell Concentration ◽  
Oxygen Transfer Rate ◽  
Aerobic Growth ◽  
Shake Flasks ◽  
Maximum Cell ◽  
Maximum Cell Concentration

PRODUCTION OF DOCOSAHEXAENOIC ACID (DHA) FROM Thraustochytrium sp. ATCC 26185 USING DIFFERENTS NITROGEN CONCENTRATIONS

2015 ◽  
Vol 32 (1) ◽  
Author(s):  
Valcenir Júnior Mendes Furlan ◽  
MARIA DO CASTELO PAULO ◽  
Victor Wegner Maus ◽  
Júlia Ferreira ◽  
Irineu Batista ◽  
...  
Keyword(s):  
Cell Concentration ◽  
Glucose Consumption ◽  
Batch Process ◽  
Human Organism ◽  
Fed Batch ◽  
Cell Biomass ◽  
Oleaginous Microorganism ◽  
Nitrogen Concentrations ◽  
Maximum Cell ◽  
Maximum Cell Concentration

Polyunsaturated fatty acids (PUFAs) of the type ω3 and ω6 play important physiological functions in human organism, since they are components of cell membranes and brain cells; they decrease the levels of triglycerides and can prevent the incidence of coronary heart disease. Various parameters, including concentration of the nitrogen source in the cultivation of oleaginous microorganisms have been reported to be essential in the biosynthesis and accumulation of PUFAs. The objective of this work is to study the effect of different concentrations of total nitrogen (TN) in the production of PUFAs, especially DHA, from Thraustochytrium sp. ATCC 26185. The concentrations of TN evaluated were 2.4 and 0.8 g/L (batch) and 0.009 g/L (hourly) under fed-batch process. The content of cell biomass, glucose consumption, TN and production of PUFAs was determined. The major composition of the PUFAs in Thraustochytrium sp. ATCC 26185 cell biomass were DPA ω6 (21-25%) and DHA (69-73%), regardless of the type and time of culture. The maximum cell concentration obtained (30.2 g/L) was using 2.4 g/L TN in 168 h of culture. With this same concentration of TN it was possible to produce the highest concentration of DHA (1.16 g/L) in 120 h of culture, demonstrating that the growth of Thraustochytrium sp. ATCC 26185 and yield of PUFAs are dependent on the concentration TN source available for consumption of this oleaginous microorganism, as well as culture time.

scholarly journals 3-D Wire Cloth Electrode for Higher Throughput DielectrophoreticSeparation of Bacterial Cell

2019 ◽  
Vol 8 (6S4) ◽  
pp. 381-385
Keyword(s):  
Flow Rate ◽  
Cell Separation ◽  
Cell Concentration ◽  
Surface Areas ◽  
Total Percentage ◽  
Textile Technology ◽  
Percentage Yield ◽  
Maximum Cell ◽  
Wire Cloth ◽  
Maximum Cell Concentration

Dielectrophoresis (DEP) is one of an alternative way for cell separation. It has mainly been limited to processing small volumes due to constrain in fabrication of microelectrode over large surface areas. This work incorporated the wire cloth electrode fabricated using textile technology into a high throughput chamber experiment. The plain-weave wire cloth consists of 71µm stainless steel wires as the microelectrode arrays hold together by polyester yarn warp. This work determines the cell separation yield with parameters on applied voltage, flow rate and cell concentration as well as its optimized variables on the chamber width of 1.2cm and 2.5cm. The optimum voltage achieved was 30Vpk-pk, with flow rate of 3.5 ml/min and maximum cell concentration of 2.08x107 cells/ml. In chamber width comparison, 1.2cm width chamber gives better total percentage yield of 96% than the 2.5cm width chamber of 85% total percentage yield.

Exogenous application of methyl jasmonate induces defense response and develops tolerance against mungbean yellow mosaic India virus in Vigna mungo

2019 ◽  
Vol 46 (1) ◽  
pp. 69 ◽  
Author(s):  
Nibedita Chakraborty ◽  
Jolly Basak
Keyword(s):  
Methyl Jasmonate ◽  
Molecular Mechanisms ◽  
Stability Index ◽  
Protective Role ◽  
Membrane Stability ◽  
Vigna Mungo ◽  
Marker Genes ◽  
Exogenous Application ◽  
Ros Homeostasis

Vigna mungo (L.)Hepper is an economically important leguminous crop in south-east Asia. However, its production is severely affected by Mungbean yellow mosaic India virus (MYMIV). It is well established that methyl jasmonate (MeJA) is effective in inducing resistance against pathogens in several plants. To assess the role of MeJA in developing MYMIV tolerance in V. mungo, we analysed time-dependent biochemical and molecular responses of MYMIV susceptible V. mungo after exogenous application of different MeJA concentrations, followed by MYMIV infection. Our analysis revealed that exogenous application of different concentrations of MeJA resulted in decreased levels of malondialdehyde with higher membrane stability index values in MYMIV susceptible V. mungo, suggesting the protective role of MeJA through restoring the membrane stability. Moreover, the level of expression of different antioxidative enzymes revealed that exogenous MeJA is also very effective in ROS homeostasis maintenance. Enhanced expressions of the defence marker genes lipoxygenase and phenylalanine ammonia-lyase and the reduced expression of the MYMIV coat-protein encoding gene in all MeJA treated plants post MYMIV infection revealed that exogenous application of MeJA is effective for MYMIV tolerance in V. mungo. Our findings provide new insights into the physiological and molecular mechanisms of MYMIV tolerance in Vigna induced by MeJA.

scholarly journals Discrimination of drought tolerance in a worldwide collection of safflower (Carthamus tinctorius L.) genotypes based on selection indices

2021 ◽  
Vol 117 (1) ◽  
pp. 1
Author(s):  
Pooran GOLKAR ◽  
Esmaeil HAMZEH ◽  
Seyed Ali Mohammad MIRMOHAMMADY MAIBODY
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Geometric Mean ◽  
Resistance Index ◽  
Stability Index ◽  
Carthamus Tinctorius ◽  
Tolerance Index ◽  
Breeding Programs ◽  
Drought Tolerance Indices ◽  
Tolerance Indices

<p>Improvement of elite safflower genotypes for drought-tolerance is hampered by a deficiency of effective selection criteria. The present study evaluated 100 genotypes of safflower in terms of their drought tolerance over a period of three years (2016–2018) under both non-stress and drought-stress conditions. The eight drought-tolerance indices of tolerance index (TOL), mean productivity (MP), geometric mean productivity (GMP), stress susceptibility index (SSI), stress tolerance index (STI), yield stability index (YSI), drought resistance index (DI), and harmonic mean (HARM) were calculated based on seed yield under drought (Y<sub>s</sub>) and non-drought (Y<sub>p</sub>) conditions. A high genetic variation was found in drought tolerance among the genotypes studied. The MP, GMP, and STI indices were able to discriminate between tolerant and drought-sensitive genotypes. Plots of the first and second principal components identified drought-tolerant genotypes averaged over the three study years. Cluster analysis divided the genotypes into three distinct groups using the drought tolerance indices. Ultimately, eight genotypes (namely, G<sub>3</sub>, G<sub>11</sub>, G<sub>13</sub>, G<sub>24</sub>, G<sub>33</sub>, G<sub>47</sub>, G<sub>58</sub>, and G<sub>61</sub>) from different origins were detected as more tolerant to drought stress suitable for use in safflower breeding programs in drought-affected areas. The most tolerant and susceptible genotypes could be exploited to produce mapping populations for drought tolerance breeding programs in safflower.</p>

Sign in / Sign up

Export Citation Format

Share Document