scholarly journals Modeling Of Chlorophyll a Content in Microalgae Cultures

2020 ◽  
Vol 15 (2) ◽  
pp. 158-171 ◽  
Author(s):  
A.S. Lelekov ◽  
R.P. Trenkenshu
Keyword(s):  
Chlorophyll A ◽  
Arthrospira Platensis ◽  
Basic Model ◽  
Cell Structures ◽  
Kinetic Coefficients ◽  
Microalgae Biomass ◽  
Species Specific ◽  
Specific Growth Rates ◽  
Chlorophyll A Content ◽  
Good Agreement

The work focuses on mathematical modeling of light influence mechanisms on chlorophyll a content in microalgae biomass. The well-known qualitative models are based on concepts of synthesis and photodestructive oxidation of chlorophyll a, however the later for some microalgae species seems doubtful. We proposed an alternative approach to modeling the light-dependent chlorophyll a content in microalgae biomass. The basic model is based on generally accepted two-stage photoautotrophic growth of microalgae. At the first stage, during photosynthesis a reserve part of biomass is formed, from which the biosynthesis of cell structures occurs at the second stage. Three partial solutions of the basic system of equations describing the dependence of chlorophyll a content on the external light intensity are considered for various limiting conditions. Due to the equality of specific growth rates of formation of reserve and structural forms of biomass, the equations obtained can be used only for turbidostat cultures. Verification of the obtained equations for Arthrospira platensis allows us to estimate kinetic coefficients, the values of which are generally in good agreement with theoretically calculated ones. For approximate calculations, a simple equation is proposed that shows a good agreement with experimental data for Tetraselmis viridis (R2 = 0.98), Dunaliella tertiolecta (R2 = 0.92) and describes the results for Sceletonema costatum and Chlorella vulgaris (R2 = 0.8) quite well. Chlorophyll a refers to structural forms of biomass. The proportion of chlorophyll a in the structural biomass is about 2.5–3.5 %, it is a species-specific parameter.

Modified equation of chlorophyll content in microalgal biomass under light limitation

2020 ◽  
pp. 17-24
Author(s):  
Alexander S. Lelekov ◽  
Rudolf P. Trenkenshu ◽  
Tatyana M. Novikova
Keyword(s):  
Chlorophyll Concentration ◽  
Arthrospira Platensis ◽  
Light Limitation ◽  
Specific Rate ◽  
Microalgal Biomass ◽  
Basic Model ◽  
Microalgae Biomass ◽  
Rate Of Photosynthesis ◽  
Species Specific ◽  
Irradiation Parameter

The paper presents a modified mathematical model of light-dependent chlorophyll concentration in the microalgae biomass. The basic model is based on the concept of biomass as a sum of reserve and structural components. Considering that part of the structural biomass can turn into a reserve, the minimum irradiation parameter (“photosynthesis compensation point”) is added to the basic equation. Verification of the model on experimental data for turbidostat cultures of Tetraselmis viridis and Arthrospira platensis allowed us to evaluate species-specific coefficients. The obtained coefficient values are similar for both species. The share of chlorophyll in structural biomass is about 2 %, the maximum share of structural forms of biomass is 84 %, the economic conversion factor of reserve biomass to structural is 80–90 %, and the maximum specific rate of photosynthesis is 14–20 times higher than the rate of endogenous consumption of biomass.

scholarly journals Smart Production of Lipids as Bio-Fuel in Spirulina Platensis (=Arthrospira Fusiformis), and Bio-Oxygen and Bio-Electricity in Media Cultured in Supernatant of Digested Poultry Waste

2021 ◽  
Vol 04 (04) ◽  
Author(s):  
M.A. Satter ◽  
Keyword(s):  
Chlorophyll A ◽  
Spirulina Platensis ◽  
Culture Media ◽  
Total Biomass ◽  
Poultry Waste ◽  
Cell Weight ◽  
A Cell ◽  
The Media ◽  
Specific Growth Rates ◽  
Chlorophyll A Content

An experiment was conducted to evaluate growth performances and production of bio-fuel of Spirulina platensis (Gomont), and bio-oxygen and bio-electricity of culture media in supernatant of three different amount of digested poultry waste (DPW), and Kosaric medium (KM) as control. Three different amounts (concentrations) such as 2.0, 4.0 and 6.0 g/L poultry waste were allowed to digest under aeration. After 17 days, 700 ml grayish coloured supernatant was taken with addition of 9.0 g/L NaHCO3 and 0.50 ml/l micronutrient in 2.0 L conical flask with three replications and then autoclaved. Spirulina was inoculated to grow in these three treatments including KM (Control) after 72 hours of autoclave and then allowed to grow for a period of 14 days. This duration was estimated through repeated growth trials. The cell weight of spirulina was attained a maximum of 12.58 ± 1.25 mg/L (dry wt. basis) in KM followed by 11.46 ± 1.03, 9.16 ± 0.84 and 8.13 ± 0.73 mg/L in supernatant of 4.0, 2.0 and 6.0 g/L DPW, respectively on the 10th day of culture. Similar trend was also observed in the cases of optical density of the media contained spirulina, chlorophyll a content (mg/L), cell weight, total biomass (mg/l) and specific growth rates on the basis of cell weight and chlorophyll a. Cell weight of spirulina grown in these media had highly significant (P < 0.01) correlation with the chlorophyll a content (r = 0.993) of spirulina. Crude protein of spirulina grown in supernatant of DPW was lower than that of spirulina cultured in KM. Crude lipids as bio-fuel of spirulina cultured in supernatant of 4.0 g/L DPW was almost three times higher than that of spirulina grown in KM which may be due to high phospholipids bioaccumulation. Phosphate-P was decreased in media of DPW due to its use for high lipids biosynthesis as phospholipids. Bio-oxygen was produced higher ranged from 2.1 ± 11 mg/L on initial day to 10.20 ± 0.54 mg/L on 10th day grown in supernatant of 4.0 g/L DPW media. Bio-electricity as green electricity ranged from 135 ± 4 on initial day to 284 ± 7 mV on 10th day when spirulina cultured in supernatant of 4.0 g/L DPW which was higher than grown in other media. pH followed the similar trend like bio-oxygen and bio-electricity. It was found that the production of bio-oxygen, bio-fuel and bio-electricity had direct relation with pH in culture media of spirulina. Therefore, mass production of Spirulina platensis might be done in supernatant of 4.0 g/L digested poultry waste to get high total lipids as bio-fuel, bio-electricity and bio-oxygen.

scholarly journals Sugar and no sugar added fruit microalgae-enriched jams: a study about their physicochemical, rheological, and textural properties

2021 ◽  
Author(s):  
Zaida Natalia Uribe-Wandurraga ◽  
María Bravo-Villar ◽  
Marta Igual ◽  
Carmen Savall ◽  
Purificación García-Segovia ◽  
...  
Keyword(s):  
Food System ◽  
Textural Properties ◽  
Arthrospira Platensis ◽  
Microalgae Biomass ◽  
Textural Parameters ◽  
Weak Gel ◽  
Biomass Extract ◽  
And Control ◽  
Colour Coordinates ◽  
Control Samples

AbstractJams are preparations of fruits whose main preserving agent is sugar. Due to this, health concerns of consumers have resulted in a sugar reduction, and its replacement using alternative sweeteners and introducing new ingredients enhancing nutritional properties. In this study, four types of fruits jams (plum, strawberry, apple, and peach), with or without sugar, were prepared using two microalgae biomass, Arthrospira platensis (Spirulina) and Chlorella vulgaris, and Dunaliella salina extract as ingredients at different mix levels of concentrations, 0.10%–0.10%–0.05% respectively, for plum; 0.04%–0.00%–0.01 respectively, for strawberry; 0.06%–0.04%–0.00% respectively, for apple and 0.00%–0.01%–0.04% respectively, for peach. Physicochemical, rheological, and textural parameters were evaluated. Substitution of sugar/fructose syrup in the jam’s preparation caused changes in pH values, solid soluble content, and rheological and textural properties compared to sugar jams. Using sugar or sweeteners as isomalt, stevia and sucralose and microalgae biomass or extract showed significant changes in colour coordinates, however, these differences were not perceptible by the human eye. Jams containing microalgae biomass-extract showed higher G', G'', G*, and η* values than their corresponding control samples. All the jams presented weak-gel characteristics, distinguishing fruit jams. However, the results of weak-gel model analysis suggest that the influence of the different ingredients in the food system depends not only on their concentration but also on the interactions in the gel structure. Strawberry and apple jams showed no significant differences between microalgae biomass-extract samples and control samples, for both sugar and no sugar added jams being the best-obtained samples.

On the Question of the Chlorophyll a Content of the Photosystem II Reaction Center

1994 ◽  
Vol 98 (31) ◽  
pp. 7725-7735 ◽  
Author(s):  
H.-C. Chang ◽  
R. Jankowiak ◽  
N. R. S. Reddy ◽  
C. F. Yocum ◽  
R. Picorel ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Chlorophyll A ◽  
Reaction Center ◽  
Chlorophyll A Content

scholarly journals A study of the low-lying singlet and triplet electronic states of chlorophyll A and B

2013 ◽  
Vol 78 (11) ◽  
pp. 1775-1787 ◽  
Author(s):  
Mihajlo Etinski ◽  
Milena Petkovic ◽  
Miroslav Ristic
Keyword(s):  
Chlorophyll A ◽  
Density Functional ◽  
Chlorophyll B ◽  
Fluorescence Lifetimes ◽  
Functional Theory ◽  
Chlorophyll A And B ◽  
Vertical Ionization Potentials ◽  
Density Functional Theory Optimization ◽  
Triplet Formation ◽  
Good Agreement

Chlorophylls have been extensively investigated both experimentally and theoretically owing to the fact that they are essential for photosynthesis. We have studied two forms of chlorophyll, chlorophyll a and chlorophyll b, by means of density functional theory. Optimization of S0, S1 and T1 states was performed with the B3-LYP functional. The computed fluorescence lifetimes show good agreement with the available experimental data. The electronic adiabatic energies of S1 and T1 states are 2.09/2.12 and 1.19/1.29 eV for chlorophyll a and chlorophyll b respectively. We discussed the implications of this results on the triplet formation. Also, the calculated vertical ionization potentials shows good agreement with the experimental results.

scholarly journals The Epiphytic FernElaphoglossum luridum(Fée) Christ. (Dryopteridaceae) from Central and South America: Morphological and Physiological Responses to Water Stress

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Bruno Degaspari Minardi ◽  
Ana Paula Lorenzen Voytena ◽  
Marisa Santos ◽  
Áurea Maria Randi
Keyword(s):  
Water Stress ◽  
Water Deficit ◽  
Chlorophyll A ◽  
Tca Cycle ◽  
Photosynthetic Parameters ◽  
Relative Water ◽  
Physiological Studies ◽  
Cycle Regulation ◽  
Epiphytic Fern ◽  
Chlorophyll A Content

Elaphoglossum luridum(Fée) Christ. (Dryopteridaceae) is an epiphytic fern of the Atlantic Forest (Brazil). Anatomical and physiological studies were conducted to understand how this plant responds to water stress. TheE. luridumfrond is coriaceus and succulent, presenting trichomes, relatively thick cuticle, and sinuous cell walls in both abaxial and adaxial epidermis. Three treatments were analyzed: control, water deficit, and abscisic acid (ABA). Physiological studies were conducted through analysis of relative water content (RWC), photosynthetic pigments, chlorophyll a fluorescence, and malate content. No changes in RWC were observed among treatments; however, significant decreases in chlorophyll a content and photosynthetic parameters, including optimal irradiance (Iopt) and maximum electron transport rate (ETRmax), were determined by rapid light curves (RLC). No evidence of crassulacean acid metabolism (CAM) pathway was observed inE. luridumin response to either water deficit or exogenous application of ABA. On the other hand, malate content decreased in theE. luridumfrond after ABA treatment, seeming to downregulate malate metabolism at night, possibly through tricarboxylic acid (TCA) cycle regulation.

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