scholarly journals Growth performance and biochemical composition of nineteen microalgae collected from different Moroccan reservoirs

2016 ◽  
Vol 17 (1) ◽  
pp. 323 ◽  
Author(s):  
EL. A. IDRISSI ABDELKHALEK ◽  
B. MOHAMED ◽  
A.M. MOHAMMED ◽  
A. LOTFI
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Chemical Constituents ◽  
High Capacity ◽  
Dry Weight ◽  
Lipid Contents ◽  
Ankistrodesmus Falcatus ◽  
Carbohydrate Contents ◽  
Existing Data ◽  
Synechocystis Aquatilis

Macro- and microalgae have recently received much attention due to their valuable chemical constituents. In order to increase existing data, the authors studied nineteen microalgae species isolated from different reservoirs in the Fez region (northern Morocco), undertaking experiments to determine for each species the specific growth rate, their total amounts of proteins, carbohydrates and lipids and the influence of the growth phase on these chemical constituents. Conditions of cultivation were as follows: light intensity equal to 300 μmol photons m-2 s-1, with a temperature regime of 25/20°C (day/night) and a 16/8 (light/dark) photoperiod cycle. The growth rates of the nineteen studied species of microalgae showed a wide variation between species, ranging from 0.27 g l-1 d-1 for Chlamydomonas ovalis to 3.64 g l-1 d-1 for Chlorococcum wemmeri. Protein, carbohydrate and lipid contents varied greatly between taxa and within genera. Ankistrodesmus falcatus, Chlamydomonas ovalis, Chlorococcum sp., Hyaloraphidium contortum, Scenedesmus protuberans, and Synechocystis aquatilis tended to synthesize proteins, the concentrations exceeding 20% dry weight (DW). Ankistrodesmus falcatus, Ankistrodesmus sp., Chlorococcum wemmeri, Coenocystis sp., Isocystis sp., Lyngbya bergei, Oscillatoria amphibia, Polytoma papillatum, Scenedesmus protuberans, Scenedesmus sp. and Synechocystis aquatilis showed a high capacity for lipid storage, greater than 20% DW. For carbohydrate contents, only Scenedesmus protuberans and Scenedesmus quadricauda showed an excessive level compared to other scanned species with 29.21% and 24.76% DW, respectively.

scholarly journals Characterization of different microalgae cultivated in open ponds

2019 ◽  
Vol 41 (1) ◽  
pp. 37723 ◽  
Author(s):  
Dagon Manoel Ribeiro ◽  
Alessandro Minillo ◽  
Cinthia Aparecida De Andrade Silva ◽  
Gustavo Graciano Fonseca
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Dry Mass ◽  
Maximum Specific Growth Rate ◽  
Pseudokirchneriella Subcapitata ◽  
Western Region ◽  
Lipid Contents ◽  
The World ◽  
Main Fatty Acid

 Microalga is one of the main sources of biomasses for the production of biofuels in the 21st century. Many labs and industries around the world are seeking for more productive strains and better cultivation models. The aim of this work was to evaluate the growth and kinetic parameters of six microalgae, and the moisture and lipid contents and fatty acids profiles of the biomasses harvested at the end of each cultivation. The microalgae were isolated in the Mid-Western Region of Brazil cultivated in open pond systems. It was observed that among the six microalgae used in this work, Pseudokirchneriella subcapitata presented the higher maximum specific growth rate (μmax) (0.12 day-1). The microalgae Coelastrum sp. and P. subcapitata were the ones with the highest lipid contents, with approximately 20% of dry mass. The main fatty acid accumulated in these conditions was palmitic acid, with percentages of 59 to 69% for all microalgae evaluated. Other factors that had influenced results from cultivations in open ponds were discussed here. 

scholarly journals Poly(3-Hydroxybutyrate) Synthesis by Recombinant Escherichia coli arcA Mutants in Microaerobiosis

2006 ◽  
Vol 72 (4) ◽  
pp. 2614-2620 ◽  
Author(s):  
Pablo I. Nikel ◽  
M. Julia Pettinari ◽  
Miguel A. Galvagno ◽  
Beatriz S. Méndez
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Deletion Mutant ◽  
Specific Growth ◽  
Dry Weight ◽  
Low Oxygen ◽  
Oxygen Conditions ◽  
In The Wild ◽  
Microaerobic Conditions

ABSTRACT We assessed the effects of different arcA mutations on poly(3-hydroxybutyrate) (PHB) synthesis in recombinant Escherichia coli strains carrying the pha synthesis genes from Azotobacter sp. strain FA8. The arcA mutations used were an internal deletion and the arcA2 allele, a leaky mutation for some of the characteristics of the Arc phenotype which confers high respiratory capacity. PHB synthesis was not detected in the wild-type strain in shaken flask cultures under low-oxygen conditions, while ArcA mutants gave rise to polymer accumulation of up to 24% of their cell dry weight. When grown under microaerobic conditions in a bioreactor, the arcA deletion mutant reached a PHB content of 27% ± 2%. Under the same conditions, higher biomass and PHB concentrations were observed for the strain bearing the arcA2 allele, resulting in a PHB content of 35% ± 3%. This strain grew in a simple medium at a specific growth rate of 0.69 ± 0.07 h−1, whereas the deletion mutant needed several nutritional additives and showed a specific growth rate of 0.56 ± 0.06 h−1. The results presented here suggest that arcA mutations could play a role in heterologous PHB synthesis in microaerobiosis.

scholarly journals Cellular Microcystin Content in N-Limited Microcystis aeruginosa Can Be Predicted from Growth Rate

2001 ◽  
Vol 67 (1) ◽  
pp. 278-283 ◽  
Author(s):  
Benedict M. Long ◽  
Gary J. Jones ◽  
Philip T. Orr
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Cell Volume ◽  
Microcystis Aeruginosa ◽  
Specific Growth ◽  
Weight Ratio ◽  
Dry Weight ◽  
Cell Protein ◽  
Protein Ratio ◽  
Cell Quota

ABSTRACT Cell quotas of microcystin (Q MCYST; femtomoles of MCYST per cell), protein, and chlorophyll a(Chl a), cell dry weight, and cell volume were measured over a range of growth rates in N-limited chemostat cultures of the toxic cyanobacterium Microcystis aeruginosa MASH 01-A19. There was a positive linear relationship betweenQ MCYST and specific growth rate (μ), from which we propose a generalized model that enablesQ MCYST at any nutrient-limited growth rate to be predicted based on a single batch culture experiment. The model predicts Q MCYST from μ, μmax(maximum specific growth rate), Q MCYSTmax(maximum cell quota), and Q MCYSTmin (minimum cell quota). Under the conditions examined in this study, we predict aQ MCYSTmax of 0.129 fmol cell−1 at μmax and a Q MCYSTmin of 0.050 fmol cell−1 at μ = 0. Net MCYST production rate (R MCYST) asymptotes to zero at μ = 0 and reaches a maximum of 0.155 fmol cell−1 day−1at μmax. MCYST/dry weight ratio (milligrams per gram [dry weight]) increased linearly with μ, whereas the MCYST/protein ratio reached a maximum at intermediate μ. In contrast, the MCYST/Chla ratio remained constant. Cell volume correlated negatively with μ, leading to an increase in intracellular MCYST concentration at high μ. Taken together, our results show that fast-growing cells of N-limited M. aeruginosa are smaller, are of lower mass, and have a higher intracellular MCYST quota and concentration than slow-growing cells. The data also highlight the importance of determining cell MCYST quotas, as potentially confusing interpretations can arise from determining MCYST content as a ratio to other cell components.

THE KINETICS OF METABOLISM OF GIBBERELLA FUJIKUROI IN STIRRED CULTURE

1964 ◽  
Vol 10 (3) ◽  
pp. 407-444 ◽  
Author(s):  
A. Borrow ◽  
Sheila Brown ◽  
E. G. Jefferys ◽  
R. H. J. Kessell ◽  
Eithne C. Lloyd ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Nitrogen Uptake ◽  
Exponential Growth ◽  
Ammonium Acetate ◽  
Specific Growth ◽  
Dry Weight ◽  
Gibberella Fujikuroi ◽  
Ammonium Tartrate ◽  
Kinetics Of

Some aspects are described of the kinetics of the growth of Gibberella fujikuroi in nitrogen-limited media containing either ammonium nitrate, ammonium acetate, ammonium tartrate, urea, or glycine. Also varied were inoculum size, agitation rate, pH, and initial concentrations of glucose and nitrogen source. The significance of kinetic parameters used in this, and published studies, is discussed.A lag phase was only found on ammonium acetate media or when high concentrations of glucose were present. Early growth was exponential on all nitrogen sources. On ammonium acetate the specific growth rate decreased at a dry weight of ca. 1 mg/g WS (Whole unfiltered Sample). On ammonium nitrate, early exponential growth utilized more NH3-nitrogen than NO3-nitrogen with a concomitant decrease in pH. In the range pH 3.0–2.8 NH3-nitrogen uptake and dry weight increase ceased, but NO3-nitrogen uptake continued, and the pH increased until growth and NH3-nitrogen uptake restarted. This pattern could be repeated. Finally, exponential growth was resumed at a low specific growth rate. On glycine, urea, and ammonium tartrate media, exponential growth continued to a dry weight of about 7 mg/g WS. During this period the uptakes relative to dry weight (contributions) of glucose, nitrogen, phosphate, and magnesium remained constant and were unaffected by the rate of agitation, as also was the specific growth rate, but the latter decreased with increasing glucose concentration.A period of linear growth could follow the exponential period. The contribution of glucose was greater, and that of phosphate and magnesium less, than during exponential growth. The dry weight at which exponential growth changed to linear growth was greater the higher the rate of agitation, and this change may be a response to oxygen restriction.After nitrogen exhaustion, fat and carbohydrate accumulation in the cells largely accounted for the increase in dry weight. The specific rates of dry weight increase and glucose uptake remained constant over the lower range of initial nitrogen concentrations. Both rates decreased with increasing nitrogen over the higher range.Gibberellic acid production began at, or soon after, nitrogen exhaustion. The amount present increased linearly with time. The productivity decreased with increasing glucose concentration, and first increased and then decreased with increasing initial nitrogen. The maximum amount produced was proportional to the initial nitrogen provided. Some published results are discussed in the light of these relations.

scholarly journals Effect of soil extracts concentration on specific growth rate and lipid content of chlorella vulgaris in bolds basal medium

2014 ◽  
Vol 10 (2) ◽  
Author(s):  
Ani Idris ◽  
M. Atta ◽  
A. Bukhari
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Chlorella Vulgaris ◽  
Mass Culture ◽  
Specific Growth ◽  
Basal Medium ◽  
Dry Weight ◽  
Soil Extract ◽  
Soil Extracts ◽  
Key Factor

Effective nutrient medium is the key factor that significantly influences the specific growth rate and the final concentration of microalgae. The main objective of this study was to optimize the microalgal growth in mass culture system under the effect of soil extract in modified Bolds Basal medium. Chlorella vulgaris was grown aseptically for 10 days at five different concentrations of soil extract (10, 20, 30, 40, 50ml/L) at 25°C cultivation temperature. After 10 days of cultivation, Chlorella vulgaris showed maximum cell concentration of 5x107/ml at 30ml/L of soil extract concentration which corresponds to the maximum specific growth rate 1.56μd-1 with the doubling rate of 2.25d-1   andlipid yield of 22.74 % of dry weight.________________________________________GRAPHICAL ABSTRACT

On-line viable biomass measurement and estimation of the specific growth rate of activated sludge from municipal wastewater treatment

2001 ◽  
Vol 43 (7) ◽  
pp. 97-102 ◽  
Author(s):  
E. J. November ◽  
J. F. Van Impe
Keyword(s):  
Growth Rate ◽  
Activated Sludge ◽  
Specific Growth Rate ◽  
Municipal Wastewater ◽  
Specific Growth ◽  
Dry Weight ◽  
Municipal Wastewater Treatment ◽  
Experimental Conditions ◽  
On Line ◽  
Viable Biomass

In order to control wastewater processes, on-line measurements of important process variables are crucial. This contribution focuses on the applicability of the Biomass Monitor for on-line viable biomass measurement of activated sludge from a municipal wastewater plant. In addition, the specific growth rate of the sludge is estimated on-line, based on the information derived from the device under study. Compared to dry weight measurements, the Biomass Monitor hardware offers the advantage of a biologically more appropriate observation of the biomass by only taking into account the viable cells in the population. The optimal measurement frequency of the biomass monitoring device for the given experimental conditions has been determined. Furthermore, the capacitance readings have been correlated with off-line analyses of dry weight of the sludge during the experimental phase in which no death of cells occurred. Finally, an evaluation of the estimator of the specific growth rate including its tuning is presented.

Compositional changes in cotyledons of woody angiosperms

1976 ◽  
Vol 54 (21) ◽  
pp. 2473-2477 ◽  
Author(s):  
P. E. Marshall ◽  
T. T. Kozlowski
Keyword(s):  
Robinia Pseudoacacia ◽  
Dry Weight ◽  
Ailanthus Altissima ◽  
Fraxinus Pennsylvanica ◽  
Acer Negundo ◽  
Lipid Contents ◽  
Compositional Changes ◽  
Robinia Pseudoacacia L ◽  
Food Reserves ◽  
Carbohydrate Contents

The nature and rate of breakdown of food reserves in cotyledons varied markedly among species. Embryonic cotyledons of Acer negundo L. stored mostly proteins, whereas those of Ailanthus altissima (Mill.) Swingle were fat-storing. Fraxinus pennsylvanica Marsh, cotyledons contained nearly equal quantities of lipids and proteins (45% of dry weight for each) as did those of Robinia pseudoacacia L. (25% dry weight for each). Total nonstructural carbohydrate contents of embryonic cotyledons of Acer and Robinia (exalbuminous species) were considerably higher than those of Ailanthus or Fraxinus (albuminous species). Carbohydrate contents of Acer and Robinia cotyledons initially decreased, but carbohydrate contents of all four species increased rapidly as cotyledons became chlorophyllous and photosynthetic. Synthesis of cotyledonary chlorophyll and emergence of cotyledons occurred faster for seedlings of Acer and Robinia than for those of Ailanthus and Fraxinus. Protein and lipid contents of cotyledons of all four species declined as cotyledons matured after germination.

scholarly journals Influence of Carbon Source on Nitrate Removal by Nitrate-TolerantKlebsiella oxytoca CECT 4460 in Batch and Chemostat Cultures

1998 ◽  
Vol 64 (8) ◽  
pp. 2970-2976 ◽  
Author(s):  
Guadalupe Piñar ◽  
Karin Kovárová ◽  
Thomas Egli ◽  
Juan L. Ramos
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Nitrate Removal ◽  
Dry Weight ◽  
Specific Rate ◽  
Continuous Cultures ◽  
Batch Cultures ◽  
Chemostat Cultures ◽  
C And N

ABSTRACT The nitrate-tolerant organism Klebsiella oxytoca CECT 4460 tolerates nitrate at concentrations up to 1 M and is used to treat wastewater with high nitrate loads in industrial wastewater treatment plants. We studied the influence of the C source (glycerol or sucrose or both) on the growth rate and the efficiency of nitrate removal under laboratory conditions. With sucrose as the sole C source the maximum specific growth rate was 0.3 h−1, whereas with glycerol it was 0.45 h−1. In batch cultures K. oxytocacells grown on sucrose or glycerol were able to immediately use sucrose as a sole C source, suggesting that sucrose uptake and metabolism were constitutive. In contrast, glycerol uptake occurred preferentially in glycerol-grown cells. Independent of the preculture conditions, when sucrose and glycerol were added simultaneously to batch cultures, the sucrose was used first, and once the supply of sucrose was exhausted, the glycerol was consumed. Utilization of nitrate as an N source occurred without nitrite or ammonium accumulation when glycerol was used, but nitrite accumulated when sucrose was used. In chemostat cultures K. oxytoca CECT 4460 efficiently removed nitrate without accumulation of nitrate or ammonium when sucrose, glycerol, or mixtures of these two C sources were used. The growth yields and the efficiencies of C and N utilization were determined at different growth rates in chemostat cultures. Regardless of the C source, yield carbon (YC) ranged between 1.3 and 1.0 g (dry weight) per g of sucrose C or glycerol C consumed. Regardless of the specific growth rate and the C source, yield nitrogen (YN) ranged from 17.2 to 12.5 g (dry weight) per g of nitrate N consumed. In contrast to batch cultures, in continuous cultures glycerol and sucrose were utilized simultaneously, although the specific rate of sucrose consumption was higher than the specific rate of glycerol consumption. In continuous cultures double-nutrient-limited growth appeared with respect to the C/N ratio of the feed medium and the dilution rate, so that for a C/N ratio between 10 and 30 and a growth rate of 0.1 h−1 the process led to simultaneous and efficient removal of the C and N sources used. At a growth rate of 0.2 h−1the zone of double limitation was between 8 and 11. This suggests that the regimen of double limitation is influenced by the C/N ratio and the growth rate. The results of these experiments were validated by pulse assays.

scholarly journals Decolourization of chicken compost derived liquid fertilizer via synergic ultraviolet (UV) irradiation and ozonation for enhanced microalgae cultivation

2021 ◽  
Vol 287 ◽  
pp. 04013
Author(s):  
Yik Lam Kam ◽  
Man Kee Lam ◽  
Yoke Wang Cheng ◽  
Yaleeni Kanna Dasan ◽  
Sie Yon Lau ◽  
...  
Keyword(s):  
Growth Rate ◽  
Uv Irradiation ◽  
Specific Growth ◽  
Biomass Productivity ◽  
Dry Weight ◽  
Optimal Parameters ◽  
Microalgae Cultivation ◽  
Liquid Fertilizer ◽  
Decolorization Efficiency ◽  
Initial Ph

Compost-derived liquid fertilizers are uncostly and nutrient-enriched; however, its dark brown appearance limits light uptake of microalgae during autotrophic cultivation. Here, integrated UV irradiation/ozonation pretreatment was employed to decolourize the compost solution prior to microalgae cultivation. Aforesaid pretreatment could accomplish 16.52 % (8 h) or 40.88 % (24 h) decolorization efficiency by using optimal parameters (initial pH of 12, ozone concentration of 30 mg/L, and ozone flow rate of 3 L/min. Compared to untreated compost solution, microalgae Chlorella vulgaris grew better in the medium supplemented with decolourized compost solution (after 24 h UV irradiation/ozonation). For the autotrophic cultivation of C. vulgaris with 10 vol.% compost solution, UV irradiation/ozonation pretreatment eventually increases the microalgae dry weight, specific growth rate, and biomass productivity from 0.58 g/L, 0.14 d-1, and 0.040 g/(L·d) to 0.88 g/L, 0.19 d-1, and 0.065 g/(L·d), respectively. Furthermore, the lipid content of microalgae has been increased by 33.33% with pretreatment of compost solution.

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