Abstract
The paper presents data on the biotechnology of growing accumulative cultures of algae Scenedesmus quadricauda when adding organo-mineral complex drag to the culture growth medium. It is ...shown that the trace elements that make up the drug (trade name “Helavit”), at the studied concentrations, act in various ways stimulating and inhibiting the growth of algological culture. Having a different effect in the concentration range from 0.1 to 1 mg / L. The maximum positive effect is achieved with a drug concentration of 0.3 mg / l (8986 ± 120 103*cells/ ml), which can be recommended for mass cultivation of algae. A possible cause of inhibition of culture growth, at a concentration of 0.1 mg / l (6960 ± 115 103*cells/ ml), are the inhibitory effects of copper and iodine ions.
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.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
To reduce the use of chemical fertilizers and maximize agricultural yields, the use of microalgae extracts as biostimulants has recently attracted significant attention due to their ...favourable impact on both plant growth and their ability to induce tolerance towards environmental stressors. Lettuce (Lactuca sativa) is one of the most important fresh vegetables that often requires applications of chemical fertilizers to increase quality and productivity. Accordingly, the purpose of this study was to analyse the transcriptome reprogramming of lettuce (L. sativa) seedlings in response to either Chlorella vulgaris or Scenedesmus quadricauda extracts by applying an RNAseq approach. Differential gene expression analysis revealed that the core gene set that responded to microalgal treatments in a species-independent manner includes 1330 clusters, 1184 of which were down-regulated and 146 up-regulated, clearly suggesting that the repression of gene expression is the main effect of algal treatments. The deregulation of 7197 transcripts in the C. vulgaris treated seedlings compared to control samples (LsCv vs. LsCK) and 7118 transcripts in the S. quadricauda treated seedlings compared to control samples (LsSq vs. LsCK) were counted. Although the number of deregulated genes turned out to be similar between the algal treatments, the level of deregulation was higher in LsCv versus LsCK than in LsSq versus LsCK. In addition, 2439 deregulated transcripts were observed in the C. vulgaris treated seedlings compared to S. quadricauda treated samples (LsCv vs. LsSq comparison) suggesting that a specific transcriptomic profile was induced by the single algal extracts. ‘Plant hormone signal transduction’ category includes a very elevated number of DEGs, many of them specifically indicating that C. vulgaris actives both genes involved in the auxin biosynthesis and transduction pathways, whereas S. quadricauda up-regulates genes implicated in the cytokinin biosynthesis pathway. Finally, algal treatments induced the deregulation of genes encoding small hormone-like molecules that are known to act alone or by interacting with major plant hormones. In conclusion, this study offers the groundwork to draw up a list of putative gene targets with the aim of lettuce genetic improvement that will allow a limited or even null use of synthetic fertilizers and pesticides in the management of this crop.
A crucial challenge is to meet food demands along with improving agricultural sustainability. The use of microalgae extracts as biostimulants has recently attracted significant attention due to their favourable impact on crop growth, yields, quality, nutrient uptake and tolerance to abiotic stresses. In this work, the transcriptomic profile of lettuce seedling subjected to either Chlorella vulgaris or Scenedesmus quadricauda treatments was analysed taking into account that lettuce is one of the most important fresh vegetables that often requires applications of chemical fertilizers. Among the two microalgae extracts, C. vulgaris induced a qualitatively and quantitatively deeper response than that obtained using S. quadricauda extract, although both treatments led to ameliorated morpho-biometric parameters. ‘Phytohormones’ is the category including several differentially expressed genes showing that C. vulgaris activates both the auxin biosynthesis and transduction pathways whereas S. quadricauda up-regulates the cytokinin biosynthesis pathway, probably because they are rich in different amounts and types of beneficial components.
Chronic effects of the ionic liquid C4mimCl (mp 73 °C) towards the microalga, Scenedesmus quadricauda were studied by flow cytometry, monitoring multiple endpoints of cell density, esterase activity, ...membrane integrity, reactive oxygen species and chlorophyll fluorescence. Toxicity was clearly in evidence, and although increased esterase activity indicated hormesis during initial exposure to C4mimCl, inhibition of both esterase activity and chlorophyll fluorescence became apparent after 3 days. Cell density was also decreased by culturing with C4mimCl, but this effect was clearly concentration-dependent and only became significant during the second half of the experiment. In contrast, C4mimCl had only a modest effect on reactive oxygen species (ROS) and caused little damage to cell membranes.
•Use of an advanced biological technique, flow cytometry, to elucidate ionic liquid toxicity.•Chronic effects of ionic liquid.•Membrane integrity and ROS studied.•Mechanism of ionic liquid toxicity.
C4mimCl significantly inhibited esterase activity, chlorophyll fluorescence and cell density, having only a modest effect on reactive oxygen species and cell membranes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Lipase was immobilized on biosilica-polymer particle for biodiesel production.•S. quadricauda oil was used to produce biodiesel at 35°C for 24h reaction time.•96.4% yield of biodiesel from crude ...algal oil with immobilized lipase.•The activity retention was 76% after six cycles of transesterification.
Enzymatic transesterification reactions for biodiesel production require harsh conditions, which require methods of enzyme stability enhancements. In this study, we present covalently immobilized lipase on the biosilica-polymer composite as a viable method to obtain enzymes with enhanced stability in such harsh conditions. The fresh water microalgae Scenedesmus quadricauda was cultivated in a batch photo-bioreactor with CO2 aeration, and urea was supplied as nitrogen source (0.075gL−1). Under optimized conditions, the amount of extracted oil was around 29.6%. Finally, the algal oil was utilized for production of biodiesel via enzymatic transesterification reaction which were performed in n-hexane using the free and immobilized lipase preparations. Fatty acid methyl ester (FAME) components were determined using gas chromatography–mass spectrophotometry (GC–MS). The conversion of algal oil to biodiesel was found to be 85.7% and 96.4%, with the free and immobilized enzyme, respectively. The immobilized lipase was highly stable and only 17% of activity was lost after 6 cycles repeated uses.
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GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Microalgae are ideal candidates for bioremediation and biotechnological applications. However, salinity and nutrient resource availability vary seasonally and between cultivation sites, potentially ...impacting on biomass productivity. The aim of this study was to screen pollutant-tolerant freshwater microalgae (Desmodesmus armatus, Mesotaenium sp., Scenedesmus quadricauda and Tetraedron sp.), isolated from Tarong power station ash-dam water, for their tolerance to cultivation at a range of salinities. To determine if biochemical composition could be manipulated, the effects of 4-day nutrient limitation were also determined. Microalgae were cultured at 2, 8, 11 and 18 ppt salinity, and nutrient uptake was monitored daily. Growth, total lipid, fatty acid (FA), and amino acid contents were quantified in biomass harvested while nutrient-replete and, after 4 days, nutrient-deplete. D. armatus showed the highest salinity tolerance actively growing in up to 18 ppt while Mesotaenium sp. was the least halotolerant with decreasing growth rates from 11 ppt. However, Mesotaenium sp. at 2 and 8 ppt had the highest biomass productivity and nutrient requirements of the four species, making it ideal for nutrient remediation of eutrophic freshwater effluents. Salinity and nutrient status had minimal influence on total lipid and FA contents in D. armatus and Mesotaenium sp., while nutrient depletion induced an increase of total lipid and FAs in S. quadricauda and Tetraedron sp., which was further increased with increasing salinity. As none of the growth conditions affected amino acid profiles of the species, these findings provide a basis for species selection based on site-specific salinity conditions and nutrient resource availability.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In current study isolates of two native microalgae species were screened on the basis of growth kinetics and lipid accumulation potential. On the basis of data obtained on growth parameters and lipid ...accumulation, it is concluded that Scenedesmus dimorphus has better potential as biofuel feedstock. Two of the isolates of Scenedesmus dimorphus performed better than other isolates with respect to important growth parameters with lipid content of ~30% of dry biomass. Scenedesmus dimorphus was found to be more suitable as biodiesel feedstock candidate on the basis of cumulative occurrence of five important biodiesel fatty acids, relative occurrence of SFA (53.04%), MUFA (23.81%) and PUFA (19.69%), and more importantly that of oleic acid in its total lipids. The morphological observations using light and Scanning Electron Microscope and molecular characterization using amplified 18S rRNA gene sequences of microalgae species under study were also performed. Amplified 18S rRNA gene fragments of the microalgae species were sequenced, annotated at the NCBI website and phylogenetic analysis was done. We have published eight 18S rRNA gene sequences of microalgae species in NCBI GenBank.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Estrogens, a group of steroid hormones, are serious environmental pollutants due to their persistence, ubiquity, and endocrine-disrupting toxicity. Natural and synthetic estrogens, such as ...17β-estradiol (E2) and 17α-ethinylestradiol (EE2), respectively, have been found in the influent of municipal wastewater treatment plants. The removal and biotransformation of mixed or single E2 and EE2 by six microalgal species, including three local isolates of
Chlamydomonas
sp. (WW),
Chlorella
sp. (2f5aia), and
Chlorella
sp. (1uoai) and three commercially available species, namely
Scenedesmus quadricauda
(=
Desmodesmus communis
) (SQ),
Selenastrum capricornutum
(SC), and
Chlorella vulgaris
(CV), were compared. The biological removal of estrogen was incubation time- and species-dependent. Among six species, SC had the highest removal ability for both E2 and EE2; their removal increased with incubation time and achieved 93.9 and 75.3 % removal, respectively, at the end of incubation. After 7-day incubation, the removal percentage of mixed EE2 by SC was significantly higher than that of single EE2 (
P
≤ 0.05). Differences in the removal percentages of E2 and EE2 between commercial and local species were not significant, as reflected by the comparable removal efficiency among three
Chlorella
species, CV, 1uoai, and 2f5aia, with the highest removal of E2, either in mixed or in single treatment, at day 2. In all species, the percentages of E2 or EE2 taken up into cells were very low (0.2–9.6 %) when compared to the respective biological removal percentages. E2 was easily transformed into estrone (E1) and some unknown products by all microalgal species, while the products for EE2 transformation could not be identified due to the limited availability of the standards for metabolites.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Pseudokirchneriella subcapitata is a sickle-shaped freshwater green microalga that is normally found in unicellular form. Currently, it is the best known and most frequently used species of ...ecotoxicological bioindicator because of its high growth rate and sensitivity to toxicants. However, despite this organism's, our knowledge of its cell biology-for example, the patterns of nuclear and cytoplasmic division in the mitotic stage-is limited. Although it has been reported that P. subcapitata proliferates by popularity forming four daughter cells (autospores) through multiple fission after two nuclear divisions, here, we report two additional reproductive patterns by which two autospores are formed by binary fission ("two-autospore type") and eight autospores are formed by multiple fission ("eight-autospore type"). Moreover, we found that cell reproductive patterns differed markedly with the culture conditions or with exposure to either of two typical toxicants, potassium dichromate (K2Cr2O7) and 3,5-dichlorophenol (3,5-DCP). The eight-autospore type occurred at the highest frequency in the early phase of culture, but it disappeared under 3,5-DCP at 2.0 mg/L. Under 0.3 mg/L K2CrO7 (Cr(VI)) the eight-autospore type took substantially longer to appear than in control culture. The two-autospore type occurred only in the late phase of culture. To our knowledge, this is the first detailed evaluation of the reproductive patterns of P. subcapitata, which changed dramatically in the presence of toxicants. These findings suggest that observation of the reproductive patterns of P. subcapitata will help to elucidate different cell reactions to toxicants.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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