Scenedesmus Quadricauda Research Articles

Effects of dietborne cadmium on life history and secondary production of a tropical freshwater cladoceran.

The presence of metals in aquatic environments has increased worldwide. Environmental assessments of metals in freshwater ecosystems presume that toxicity is mainly caused by aqueous exposure, but dietborne exposure (contaminated food) in zooplankton may occur because microalgae carry metal ions through adsorption/absorption of dissolved metal species, resulting in toxic effects once ingested by the animals. However, official regulations for ecotoxicological assays in most countries do not consider the toxic effects caused by dietborne exposure. Here, we provide life history parameters and secondary production of Simocephalus serrulatus (Koch 1841) (Cladocera: Daphniidae) fed with cadmium (Cd) contaminated algae during a 21-day bioassay. The microalgae Chlorophyceae Scenedesmus quadricauda was exposed for 96h to dissolved Cd concentrations of 0.03; 5.87; 12.27 and 22.27µg Cd l(-1) (equivalent to 1.6×10(-10); 3.2×10(-8); 6.7×10(-8); 1.2×10(-7)moll(-1)) that resulted in algae internal Cd burdens of 0.004; 0.032; 0.270 and 0.280pg Cd cell(-1), respectively. Significant toxic effects on life history parameters of S. serrulatus were observed. Time of embryonic development, generation time and age at first reproduction (primipara) showed significant delay. Length at first reproduction, number of eggs and clutches produced per female, hatching percentage, body length, survival and feeding rates were significantly reduced. Secondary production, that is, accumulated biomass for growth and reproduction, decreased significantly with dietborne Cd concentrations. Our results emphasize that food can be an important source of metals to zooplankton in aquatic ecosystems. Environmental regulations should consider the diet in ecotoxicological assessments. Furthermore, secondary production may be considered as a suitable endpoint in ecotoxicity tests.

Application of barley straw to dammed river for algal control

In 1970s, barley straw has been known to be capable of controlling algal growth. In vitro and in situ experiments were performed to investigate the effects of barley straw on algal growth inhibition substances. In addition, its ecotoxicity and the algal growth inhibition substances extracted from barley straw were examined. In the in vitro experiment, barley straw and retinaspora leaf treatment groups caused significant decreases (p value < 0.05) in the number of cells in Anabaena affinis, Microcystis aeruginosa, and Scenedesmus quadricauda compared with the control group. However, the treatment group, which applied 0.2g of barley straw, showed a tendency of increasing the number of cells in S. quadricauda compared with the control group. It reveals that types of algae and proper applications of barley straw are important to inhibit algal growth. In addition, the barley straw showed almost no ecotoxicities in ecotoxicity experiments while the retinaspora leaf showed a certain degree of ecotoxicity (Toxicity unit >36). In the in situ experiment, algal growth was inhibited by barley straw. In particular, diatoms exhibited a tendency of decreasing the number of algal cells compared with blue-green algae. It shows that the barley straw does not inhibit the growth of all algae and shows different effects according to types of algae. The algal growth inhibition substances were extracted from the barley straw and tested. It was found that a ferulic acid in various phenol compounds affected the algal growth most.

Whole-Cell Protein Profiles of Disintegrated Freshwater Green Algae and Cyanobacterium

ABSTRACTThe influence of cultivation methods and postharvesting treatment on protein profiles of green freshwater microalgae Chlorella kessleri, Scenedesmus quadricauda, and Chlorella sp. and cyanobacterium Spirulina platensis were evaluated. The comparison of protein profiles in algal biomass originated from the autotrophic cultivation in an outdoor open circulating cascade-type cultivation apparatus in thin-layer, a solar photobioreactor, and from the heterotrophic cultivation regime in a fermenter. All tested algae contained protein bands in the area between 14.3–27 and 70–116 kDa. Protein profiles revealed much higher heterogenity in the area between 30–70 kDa.

Physiology and methodology of chromium toxicity using alga Scenedesmus quadricauda as model object

Physiological responses of Scenedesmus quadricauda to Cr(VI) and Cr(III) excess were studied in buffer with circumneutral pH (6.5). Total Cr content was similar in low (1μM of both oxidation states) but higher in 10μM Cr(VI) treatment and high accumulation potential was detected (80–82% and 41–65% in 1 and 10μM treatments, respectively). Specific fluorescence indicator (6-((anthracen-9-yl) methyleneamino)-2H-chromen-2-one) confirmed partial reduction of Cr(VI) to Cr(III) under exposure conditions. Viability and chlorophyll autofluorescence were more depleted by Cr(VI) while Cr(III) stimulated increase in ROS and lipid peroxidation. Antioxidative enzyme activities showed significantly higher values in 10μM treatments of both Cr oxidation states. Depletion of mitochondrial proteins was not reflected in alteration of total soluble proteins indicating sensitivity of this organelle to Cr and TTC test showed no clear oxidation state-related effect. In this view, “Cr(VI) is not more toxic than Cr(III)” at least for some parameters. Subsequent study with the application of 10μM Cr(VI) confirmed that HEPES buffer is more suitable exposure solution for toxicological studied than water or inorganic salts (higher chlorophyll autofluorescence was observed) and pH 6.5 is more suitable than low or high pH (4.5 or 8.5) in terms of Cr uptake. Another known Cr(III) fluorescence indicator (naphthalimide–rhodamine) also confirmed partial reduction of Cr(VI) to Cr(III) at acidic pH but only traces were seen at alkaline pH.

Biosorption of Cd and Pb ions from aqueous solutions by biomass of the green microalga, Scenedesmus quadricauda

In this study, the dry biomass of green microalgae Scenedesmus quadricauda was used as a biosorbent to remove Cd and Pb from aqueous solutions. The effect of contact time, solution pH, the initial metal concentration, and biosorbent dose on the removal efficiency of metals from synthetic solutions was investigated. The metal adsorption was relatively fast, and the equilibrium times for both metals were between 30 and 60 min, with the maximum biosorption of Cd and Pb being 66 and 82 %, respectively, at pH 5. Biosorption of Cd and Pb by the biomass followed a pseudo-second-order kinetic model. The biosorption of the metals was better fitted by Langmuir models rather than that by Freundlich. Based on the Langmuir model, the maximum biosorption capacity of S. quadricauda dry biomass for Cd and Pb was predicted to be 135.1 and 333.3 mg g−1, respectively, at pH 5, corresponding to the obtained experimental values. Desorption of both metals was reached up to 90 % using 0.5 M HNO3; however, the capacity of algal biomass was decreased after the first adsorption-desorption cycle. The removal efficiency of Cd and Pb from industrial wastewater was 65 and 69 %, respectively.

Biotransformation of the flame retardant tetrabromobisphenol‐A (TBBPA) by freshwater microalgae

Tetrabromobisphenol-A (TBBPA) is the most widely used brominated flame retardant. However, little is known about its biotransformation by algae in aquatic environments. The authors investigated transformations of TBBPA by 6 freshwater green microalgae and identified its transformation products. Transformation experiments were conducted under axenic conditions in a laboratory for 10 d. The results showed that TBBPA could be transformed by the selected microalgae, with nearly complete removal by Scenedesmus quadricauda and Coelastrum sphaericum following 10-d incubation. Five transformation products were positively identified by mass spectrometry: TBBPA sulfate, TBBPA glucoside, sulfated TBBPA glucoside, TBBPA monomethyl ether, and tribromobisphenol-A. The mechanisms involved in the biotransformation of TBBPA include sulfation, glucosylation, O-methylation, and debromination, which could be an important step for its further degradation. This suggests that microalgae can play an important role in the fate of TBBPA in aquatic environments. The present study is the first report on algal transformation of TBBPA, and the proposed transformation products could have significant environmental implications.

The effect of phenols on the parameters of chlorophyll fluorescence and reactions of P700 in green algae Scenedesmus quadricauda

The effect of phenols, present in drains of the tsellyulozo-paper industry, on photosynthesis of the microalgae Scenedesmus quadricauda has been studied. The analysis of induction curves of the slowed-down fluorescence and light curves of non-photochemical quenching of chlorophyll fluorescence of microalgae Scenedesmus quadricauda is carried out. It was observed that energization of photosynthetic membranes was inhibited at low concentration of phenol and pyrocatechin (0.1 mM). At higher concentrations phenol and pyrocatechin inhibited electron transport in FSII and increased a share of QB not restoring centers. As a result of it the rate of P700 pigment regeneration slowed down. The results obtained indicate that parameters of induction curves of the fast and slowed-down fluorescence can be used for detecting phenol and pyrocatechin in the environment at early stages of toxic effects.

Ecological and toxicological assessment of water and bottom sediments in the Novosibirsk Reservoir

The toxicological state of individual parts of the Novosibirsk Reservoir was assessed with the help of bioassay tests of water and water extracts from bottom sediments with the use of two species of protococcus algae (Scenedesmus quadricauda (Turp.) Breb., Chlorella vulgaris Beijer) and two species of entomostracans (Daphnia magna Straus, Ceriodaphnia affinis Lillijeborg). It was found that the Ob R. near Kamenon-Ob is more polluted in terms of water and less polluted in terms of bottom sediments, compared with those in the lower part of the reservoir. The bioassay results are in agreement with the results of benthos-based bioindication and studies of chlorophyll a and pollutant concentrations in water.

Growing Scenedesmus quadricauda in used culture media: is it viable?

Large-scale cultures of freshwater microalgae species demand high volumes of water used for culture media preparation. The recycling of culture media may help decrease cultivation costs, use valuable nutrients that may still remain in the medium after use and make it a green production system. This work investigated the effects of using culture media up to three times to grow Scenedesmus quadricauda. After a first use, culture media were either supplemented with nitrogen (N) and phosphorus (P) or with all nutrients of the medium composition. The effects of used culture media on the algae were verified through chlorophyll a concentrations, number of cells per coenobium, population density, growth rates, and biochemical composition (lipid classes, proteins, and carbohydrates). Cells were harvested through centrifugation before each culture medium use. The results showed that all nutrients should be added to the used medium at each new inoculation; protein/carbohydrate ratios were the best indicator of cell physiological status (higher in controls and lower in used media), and hydrocarbons accounted for 20 % of total lipids in controls and were produced under healthy conditions in S. quadricauda. According to the present results, at least three culture medium uses may be performed without affecting biomass yield, and it may be as promising as fresh medium for general biomass applications, such as biofuels production, but we do not recommend its reuse for fine biomass applications. Even though cells grew well in recycled media with all nutrients added, they were not as healthy as the ones in the control.

Nutrient removal and lipid accumulation properties of newly isolated microalgal strains

In this work, four microalgae including Chlorella sp. SDEC-10, Chlorella ellipsoidea SDEC-11, Scenedesmus bijuga SDEC-12 and Scenedesmus quadricauda SEDC-13 isolated from a local lake have been investigated for the properties of growth, nutrient removal and lipid accumulation in synthetic sewage. Their biomass ranged between 0.4 and 0.5g/L. The total phosphorus removal efficiency of four strains was nearly 100%, but in the case of total nitrogen and ammonium the removal efficiency was relatively low. Their lipid content, ranging from 25.92% to 27.76% and corresponding to the lipid productivity 7.88–18.08mg/L/d, was higher than that obtained in BG-11. Palmitic acid and oleic acid were the predominant compositions found through fatty acids analysis. S. quadricauda SDEC-13 performed best both in nutrient removal and in lipid production among the four strains.

The Indigo Blue Dye Decolorization Potential of Immobilized Scenedesmus quadricauda

In this study, Scenedesmus quadricauda ABU12 was immobilized with sodium alginate to determine its potential for decolorizing indigo blue dye under different incubation conditions. The microalga was incubated at different pH (6.5–9.5), biomass concentrations (0.1–1.0 g l−1), dye concentrations (12–75 mg l−1) and temperatures (25–40°C). The concentration of biomass used significantly determined the rate of dye decolorization, as the lowest biomass concentration (0.10 g) was able to completely decolorize the dye by day 3, while the highest biomass concentration (1.00 g l−1) attained 100 % decolorization on day 4. Neutral pHs supported the highest dye decolorization rates compared alkaline pHs. The rate of dye decolorization had a linear relationship with the concentration of the dye in solution as increasing dye concentration in the medium significantly reduced the rate of decolorization (p < 0.05). At 25°C, the rate of dye decolorization was consistently higher from day 2 to the end of the experiment. Infra-red analyses of the algal biomass and the dye solution was done in Kbr by pressing between flat aperture plates of sodium chloride and scanning from 4,000 to 625 cm−1. This revealed the presence of functional groups associated with the biomass and dye that provided possible explanations for the decolorization of the dye under the different incubation conditions. These results showed that immobilized S. quadricauda is capable of decolorizing indigo blue dye at low biomass when immobilized with sodium alginate. However, this was dependent on the incubation temperature and dye concentration.

Effect of phytohormones on the growth of Scenedesmus quadricauda (Turp.) Bréh

Studies were made an the effect of indole-3-acetic acid (IAA), gibberellic acid (GA), kinetin (Kin), and various combinations of these substances upon dry matter increments, soluble protein content, and chlorophyll levels in the cultures of &lt;em&gt;Scenedesmus quadricauda&lt;/em&gt; (Turp.) Bréb. It was found that all these phytohormones, added separately to the medium, stimulated dry matter increment and protein content, although their effect depended on the concentration and the duration of culture. Addition of various combinations of the substances under study into the medium resulted in a less pronounced increment of dry matter, whereas the content of soluble protein significantly increased. The results reflect positive reaction of &lt;em&gt;Scenedesmus quadricauda&lt;/em&gt; to the addition of phytohormones into the medium. They also suggest some differences in the action of particular hormones.

Photosynthetic responses and accumulation of mesotrione in two freshwater algae.

Mesotrione is a herbicide used for killing annual grasses and broad-leaved weeds in maize. A recent investigation has shown that mesotrione has been detected as an organic contaminant in aquatic environments and may have a negative impact on aquatic organisms. To evaluate the eco-toxicity of mesotrione to algae, experiments focusing on photosynthetic responses and mesotrione accumulation in Microcystis sp. and Scenedesmus quadricauda were carried out. Both algae treated with mesotrione at 0.05-10 mg L(-1) for 7 days reduced the photosynthetic capacity. The fluorescence of chlorophyll a, the maximal PSII activity (Fv/Fm), and the parameters (Ik, α and ETRmax) of rapid light curves (RLCs) in both algae were decreased under mesotrione exposure. The 96 h EC50 values for mesotrione on S. quadricauda and Microcystis sp. were 4.41 and 6.19 mg L(-1), respectively. The latter shows more tolerance to mesotrione. Mesotrione was shown to be readily accumulated by both species. Such uptake of mesotrione led to the rapid removal of mesotrione from the medium. Overall, this study represents the initial comprehensive analyses of Microcystis sp. and S. quadricauda in adaptation to the mesotrione contaminated aquatic ecosystems.

Increase in the biomass of some green algae species in nitrate and ammonium mediums depending on auto-, mixo- or heterotrophic conditions

The increase in total dry mass and protein in cultures of &lt;em&gt;Chlorella pyrenoidosa, Scenedesmus quadricauda&lt;/em&gt; and &lt;em&gt;Ankistrodesmus acicularis&lt;/em&gt; was studied. Under autotrophic conditions, increases in dry mass were, as a rule, larger in the nitrate medium than in the ammonium one, under mixotrophic conditions the situation was reversed and in the case of heterotrophy, the individual species reacted differently. The dependence ot the protein content increase on the nitrate or ammonium form of the medium was not clear. Changes in time of the pH and rH of the mediums were followed and the interdependence of these changes with the production of biomass is discussed.

Nfluence of reducing and oxidizing compounds and of the redox potential of the medium on the biomass of Scenedesmus quadricauda (Turp.) Breb.

The influence was investigated of several concentrations of the reducing agents: cysteine, glutathione, ascorbic acid, pyracatechol and of the oxidizing agents: KMnO&lt;sub&gt;4&lt;/sub&gt;, K&lt;sub&gt;4&lt;/sub&gt;Cr&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;7&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; on the total dry weight increment and that of protein with reference to redox potential changes of the medium in &lt;em&gt;Scenedesmus quadricauda&lt;/em&gt; cultures. The culture was run in a photothermostat. It was found that the reducing compounds had as a rule a stimulating influence under 24-h illumdnation, whereas the oxidilzing agents gave the same effect when a period of 7-h darkness was applied within 24 h.

Biomass from Microalgae: An Overview

Microalgal biomass offers a number of advantages over conventional biomass such as higher productivities, use of non-productive land, reuse and recovery of waste nutrients, use of saline or brackish waters, and reuse of CO2 from power-plant flue-gas. The production of microalgal biomass reduces Greenhouse Gases (GHG) and provides biofuel as a replacement for fossil fuels. They are useful for production of food, health supplements, fodder, biofuel, aquaculture, fine chemicals and various biotechnological applications. The most commonly used marine algal cultures are Botryococcus braunii, Chlorella vulgaris, Chaetoceros muelleri, Dunaliella salina, Nannochloropsis oculata, Arthrospira maxima, Scenedesmus quadricauda. The current review provides details of the microalgal biomass with emphasis on strain selection, cultivation, strain improvement and biotechnological potentials.

Eco-toxicity of oily wastes containing TENORM

Oily wastes are considered as one of the most hazardous waste types. Additionally to petroleum components, they can contain radioactive elements. This study aimed to estimate the toxicity of four raw and two treated waste samples obtained from petroleum production yard. Eight elutriate bioassays using plants (Raphanus sativus and algae Scenedesmus quadricauda), crustacean (Daphnia magna and Thamnocephalus platyurus), rotifer (Brachionus calyciflorus), protozoa (Paramecium caudatum) and bacteria (Bacillus pumilus and luminescent commercial strain) were used. Two contact bioassays based on R. sativus and B. pumilus were applied. Total petroleum hydrocarbons (TPH) content and activity concentrations of radium, thorium and potassium were determined.

Oxidative stress, uptake and bioconversion of 5-fluorouracil in algae

Impact of cytostatic drug 5-fluorouracil (FU) and its metabolite 2-fluoro-3-alanine (FA) on green alga Scenedesmus quadricauda was studied. FA elevated fluorescence signal of reactive oxygen species (ROS) more pronouncedly than FU at 1 and 10μM doses while both ROS and reactive nitrogen species (RNS/NO) increased more expressively in 100μM FU treatment. Cellular damage staining (Acridine Orange and Calcofluor White) did no reveal substantial difference between FU and FA. Majority of free amino acids including proline was unaffected after 24h of exposure. FA depleted ascorbate peroxidase activity more than FU therefore ascorbate content (AsA) was less affected while FU stimulated glutathione reductase activity less than FA and therefore glutathione (GSH) was more depleted. Both compounds accumulated concentration-dependently with higher absolute FA amounts but FU conversion to FA was also detected. We subsequently influenced 100μM FU- and FA-induced changes using known ROS (DTT – dithiothreitol) and RNS/NO (SNP – sodium nitroprusside and PTIO – 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) modulators and results showed that PTIO depleted NO and elevated ROS while the opposite was found after SNP and DTT addition. Changes of lipid peroxidation (using BODIPY staining) confirmed that FU and FA toxicity is related to alteration of ROS/RNS balance.

Effect of indigo dye effluent on the growth, biomass production and phenotypic plasticity of Scenedesmus quadricauda (Chlorococcales)

The effect of indigo dye effluent on the freshwater microalga Scenedesmus quadricauda ABU12 was investigated under controlled laboratory conditions. The microalga was exposed to different concentrations of the effluent obtained by diluting the dye effluent from 100 to 175 times in bold basal medium (BBM). The growth rate of the microalga decreased as indigo dye effluent concentration increased (p <0.05). The EC50 was found to be 166 dilution factor of the effluent. Chlorophyll a, cell density and dry weight production as biomarkers were negatively affected by high indigo dye effluent concentration, their levels were higher at low effluent concentrations (p <0.05). Changes in coenobia size significantly correlated with the dye effluent concentration. A shift from large to small coenobia with increasing indigo dye effluent concentration was obtained. We conclude that even at low concentrations; effluents from textile industrial processes that use indigo dye are capable of significantly reducing the growth and biomass production, in addition to altering the morphological characteristics of the freshwater microalga S. quadricauda. The systematic reduction in the number of cells per coenobium observed in this study further confirms that environmental stress affects coenobium structure in the genus Scenedesmus, which means it can be considered an important biomarker for toxicity testing.

Genotoxicity of disinfection by-products (DBPs) upon chlorination of nine different freshwater algal species at variable reaction time

Nine local dominant freshwater algal species, including green algae ( Chlorella sp., Chlamydomonas sp. and Scenedesmus quadricauda ), diatom ( Navicula pelliculosa , Nitzschia palea Grunow and Synedra sp.), blue-green algae ( Microcystis sp., Chroococcus sp. and Gloeocapsa sp.) were isolated from source water reservoirs and cultivated in the laboratory. The algal biomass was chlorinated (20 °C, pH 7, residual chlorine 2 mg L −1 ). Yields of chloroform, dichloroacetic acid, trichloroacetic acid, dichloroacetonitrile and trichloroacetonitrile and genotoxicity of the chlorinated solutions at eight chlorination intervals (0.5, 1, 2, 5, 10, 30, 60 and 120 min) were determined via SOS-ChromoTest and Comet assay. The results showed that green algae and diatom were more effective disinfection by-products (DBPs) precursors than blue-green algae. Genotoxicity was shown to be chlorination time-dependent, in agreement with our previous findings, suggesting that intermediate DBPs rather than trihalomethanes or haloacetic acids were major contributors to the genotoxicity of chlorinated solutions.