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1.
Curr Microbiol ; 78(10): 3770-3781, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34487210

RESUMO

Enhanced biofuel production strategies from microalgae by employing affordable bio-waste usage are fetching significance, nowadays. This study examines the effect of VWE for enhanced biomass from new indigenous microalgal isolates, Asterarcys sp. SPC, Scenedesmus sp. KT-U, Scenedesmus sp. KTWL-A, Coelastrum sp. T-E, and Chlorella sp. TWL-B. The growth of microalgae in VWE-treated growth media showed considerable increase (1.14-2.3 folds) than control medium (without VWE). Further, two effective native microalgae were selected based on growth in VWE treatment, biomass productivity, and TAG accumulation through statistical clustering analysis. Mixotrophic batch cultivation of Scenedesmus sp. KT-U and Asterarcys sp. SPC cultivated using VWE treatment in the optimum concentration had produced significant average increase in BP (1.8 and 1.4 folds, respectively) than control (without VWE). Whereas in the lipid production phase, there was a noticeable increase in lipid yield in VWE-treated cells of lipid phase (231.8 ± 17.9 mg/L and 243.5 ± 25 mg/L) in Scenedesmus sp. KT-U and Asterarcys sp. SPC, respectively, than in control (140.5 ± 28 mg/L and 166.4 ± 23 mg/L) with considerable TAG accumulation. Thus, this study imparts strain selection process of native microalgae based on vegetable waste usage for improved yield of biomass and lipid amenable for cost-effective biodiesel production.


Assuntos
Chlorella , Microalgas , Scenedesmus , Biocombustíveis , Biomassa , Lipídeos , Verduras , Águas Residuárias
2.
Bioresour Technol ; 341: 125809, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34479141

RESUMO

A comprehensive polyphasic evaluation of a microalgal isolate Scenedesmus sp. SVMIICT1 through morphological, biochemical, photosynthetic characterization, next-generation sequencing and lipid pathway analysis was reported. The strain was cultivated photo-autotrophically, where the maximum photosynthetic yield (FV/FM) of 0.75 was observed on the 4th day with optimal PSII photochemical efficiency. Enhanced electron transport rate (ETR(I)) with inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) resulted in cyclic electron flow. A fair share of carbohydrate content (36 µg/mg) was ascribed to the presence of pyrenoid towards higher CO2 sequestration pursuant to carbon concentrating mechanism (CCM). Denovo sequencing of the genome was assembled, annotated for the prediction of gene and protein. KEGG automatic annotation server (KAAS) analysis depicted the presence of genes accompanying the biosynthesis of the glycerophospholipid pathway. Fatty acid profile represented a higher fraction of palmitic acid (C16:0; 41.6%) followed by alpha-linolenic acid (C18:3; 44.5%).


Assuntos
Microalgas , Scenedesmus , Carbono , Lipídeos , Fotossíntese
3.
Bioresour Technol ; 341: 125814, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34479143

RESUMO

The study evaluated the biosynthesis of lutein and ß-carotene by Scenedesmus sp. SVMIICT1 under five different light intensities (50, 250, 500, 750 and 1000 µE/m2/s). Liquid chromatography/mass spectrometry (LC/MS) was used to determine relative quantities of lutein and ß-carotene. Relatively, high lutein content of 1.43 ± 0.04 and 0.70 ± 0.02 mg/g was found with 50 and 500 µE/m2/s conditions respectively. ß-Carotene content was quantified as 0.15 ± 0.01, 0.1 ± 0.01 and 0.12 ± 0.02 mg/g with 50, 250 and 500 µE/m2/s conditions respectively. The light intensities altered photosystem II and photosystem I. At 50 µE intensity, high chlorophyll content and high photosystem II quantum efficiency (FV/FM) was observed. Low FV/FM ratio of around 0.3 was detected in high light intensities (750 µE and 1000 µE) due to photoinhibition. Lipid fraction increased with increasing light intensity and the fatty acid profiles were similar in all five conditions.


Assuntos
Luteína , Scenedesmus , Clorofila , Luz , Complexo de Proteína do Fotossistema II , beta Caroteno
4.
Sci Total Environ ; 790: 148222, 2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34380253

RESUMO

Greenhouse gases (GHG) emissions are widely related to climate change, triggering several environmental problems of global concern and producing environmental, social, and economic negative impacts. Therefore, global research seeks to mitigate greenhouse gas emissions. On the other hand, the use of wastes under a circular economy scheme generates subproducts from the range of high to medium-value, representing a way to help sustainable development. Therefore, the use of wastewater as a culture medium to grow microalgae strains that biocapture environmental CO2, is a proposal with high potential to reduce the GHG presence in the environment. In this work, Scenedesmus sp. was cultivated using BG-11 medium and industrial wastewater (IWW) as a culture medium with three different CO2 concentrations, 0.03%, 10%, and 20% to determine their CO2 biocapture potential. Furthermore, the concomitant removal of COD, nitrates, and total phosphorus in wastewater was evaluated. Scenedesmus sp. achieves a biomass concentration of 1.9 g L-1 when is grown in BG-11 medium, 0.69 g L-1 when is grown in a combination of BG-11 medium and 25% of industrial wastewater; both cases with 20% CO2 supplied. The maximum CO2 removal efficiency (8.4%, 446 ± 150 mg CO2 L-1 day-1) was obtained with 10% CO2 supplied and using a combination of BG-11 medium and 50% IWW (T2). Also, the highest removal of COD was reached with a combination of BG-11 medium and T2 with a supply of 20% CO2 (82% of COD removal). Besides, the highest nitrates removal was achieved with a combination of BG-11 medium and 75% IWW (T3) with a supply of 10% CO2 (42% of nitrates removal) and the maximum TP removal was performed with the combination of BG-11 medium and 25% IWW (T1) with a supply of 10% CO2 (67% of TP removal). These results indicate that industrial wastewater can be used as a culture media for microalgae growth and CO2 biocapture can be performed as concomitant processes.


Assuntos
Microalgas , Scenedesmus , Biomassa , Dióxido de Carbono , Águas Residuárias/análise
5.
Huan Jing Ke Xue ; 42(9): 4350-4357, 2021 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-34414733

RESUMO

The release of manufactured nanomaterials (MNMs) into the environment has raised concerns about combined toxicological risks, as MNMs could significantly alter the environmental behavior and fate of co-existing contaminants. Numerous studies have been published on the combined toxicity of MNMs and co-existing contaminants, but the potential mechanisms controlling the combined toxicity, especially the biological response mechanism, remain unclear. This study investigated the combined toxicity of nano-titanium dioxide (nTiO2), a typical MNM, and the heavy metal cadmium (Cd2+), using Scenedesmus obliquus as the test organism. The molecular mechanism was examined under different concentrations, using an equivalent dose (toxic ratio 1 ∶1) on S. obliquus. The results showed that the 72h-EC50 of nTiO2 and Cd2+ at the equivalent dose was significantly higher than that of single exposure, indicating an antagonistic effect. Further transcriptomics analysis revealed that the photosynthesis, chlorophyll metabolism, and starch and sucrose metabolism pathways involved in the energy metabolism of S. obliquus were significantly up-regulated in the presence of nTiO2. The arginine and proline metabolic pathways related to the anti-stress effect of algae cells also showed positive stimulation. The results of this study provide an important reference and a research basis for in-depth understanding of the environmental effects of MNMs and co-existing contaminants.


Assuntos
Clorofíceas , Nanoestruturas , Scenedesmus , Cádmio/toxicidade
6.
Bioresour Technol ; 340: 125745, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34426241

RESUMO

In this study, the effects of P concentration and light/dark condition on the distribution of P in microalgae were tracked with Scenedesmus sp.393. Results showed that different culture conditions affected the accumulation capacity and transformation of P in intracellular polymeric substances (IPS), extracellular polymeric substances (EPS), and soluble microbial products (SMP). At low P concentration (0.70 mg P/L), inorganic phosphorus (IP) absorbed in EPS (19.40%) and organic phosphorus (OP) accumulated in IPS (70.98%) were mainly P forms in microalgae. High P concentration (>21.42 mg P/L) promoted the luxury uptake and accumulation of IP by IPS, and the conversion of IP to OP. However, the adsorption of IP by EPS was inhibited when exposed to high external P concentration. Continuous illumination promoted the microalgae growth, and dark condition stimulated the P accumulation in microalgae biomass. The results of this study could provide valuable information for P recovery with microalgae.


Assuntos
Microalgas , Scenedesmus , Biomassa , Matriz Extracelular de Substâncias Poliméricas , Nitrogênio , Fósforo
7.
Physiol Plant ; 173(2): 483-494, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34427928

RESUMO

A Danish strain of the green microalgae Scenedesmus sp. was isolated, identified and characterized with respect to productivity under outdoor cultivation conditions at northern latitudes. The algae were cultivated outdoors in Denmark in closed tubular photobioreactors using only sunlight, simple inorganic nutrients and under ambient temperatures. The biomass composition was evaluated in terms of protein content and quality. The average volumetric and areal biomass productivity obtained for the Scenedesmus sp. isolate during outdoor cultivation was 0.083 g dry matter L-1 and 6.40 g dm m-2  day-1 , respectively. Thus, productivities are comparable to data reported in the literature under similar conditions. A strain-specific nitrogen to protein conversion factor of 5.5 was determined for the Scenedesmus sp. strain enabling more accurate protein estimations from simple nitrogen determination methods like Kjeldahl analysis in the future. The protein content was determined to be 52.4% of dried biomass for this Scenedesmus strain. The sum of essential amino acids was 42% which is high compared to other microalgae. The results are compared and discussed in comparison to other microalgae and soybean as a common plant protein source.


Assuntos
Microalgas , Scenedesmus , Biocombustíveis , Biomassa , Nitrogênio , Fotobiorreatores
8.
Bioresour Technol ; 341: 125766, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34416659

RESUMO

Producing biodiesel from microalgae is a promising strategy to upgrade energy structure. In this study, effects of sulfate (SO42-) on lipid synthesis of Scenedesmus obliquus (S. obliquus) cultivated in synthetic wastewater with different carbon to nitrogen (C/N) ratios regulated by ammonium (NH4+-N) and nitrate (NO3--N), separately, were investigated. The results shown that SO42- could dramatically increase cell growth preferring to NH4+-N supply. And SO42- addition could improve its carbon and nitrogen utilization potential for boosting lipid productivity leading α-linolenic acid (C18:3n3) to occupy a dominant component (38.96%) in NH4+-N group at a C/N ratio of 7.5. Additionally, SO42- could enhance the enrichment and expression of up-regulated genes annotated in key enzymes such as GK, GNPAT, CRLS, plc and DEGS involved in glycerolipid, glycerophospholipid and sphingolipid metabolic pathways, resulting in carbon metabolism enhancement and sulfatide accumulation. This study brings a comprehensive view towards nutritional regulation of lipid synthesis in microalgae.


Assuntos
Compostos de Amônio , Microalgas , Scenedesmus , Biocombustíveis , Biomassa , Carbono , Lipídeos , Nitratos , Nitrogênio , Sulfatos , Águas Residuárias
9.
J Environ Manage ; 297: 113273, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34311253

RESUMO

A palmitoleic acid-rich Scenedesmus obliquus strain SXND-02 was isolated from ammonium-containing wastewater. Biomass and lipid production were examined for this microalgal strain in photoautotrophic, heterotrophic, and mixotrophic cultivations, respectively, in order to extend its application in wastewater purification coupled with production of valued bio-products. Among the tested conditions, the microalga had better growth and higher lipid accumulation in mixotrophy. NH4Cl inhibited the microalgal growth in photoautotrophic cultivation. However, NaAc alleviated this inhibition in both heterotrophy and mixotrophy. Using 7 g L-1 NaAc and 0.5 g L-1 NH4Cl as carbon and nitrogen sources significantly increased the algal biomass and lipid yields under mixotrophic cultivation, with the highest levels up to 1.0 g L-1 and 59.88%, respectively. Fatty acid profiling indicated that palmitoleic acid was 23% in the S. obliquus SXND-02 under mixotrophic condition, which was about 21-fold higher than that in the control S. obliquus. Furthermore, this microalgal strain was tested in the chicken farm wastewater (CFW) containing high ammonium. Compared with other treatments, the S. obliquus SXND-02 cultivated in the 1/2 CFW + NaAc medium produced larger amounts of biomass (2.18 g L-1) and lipids (50.22%), and simultaneously higher removal rates of total nitrogen (TN) (80%), total ammonium nitrogen (TAN) (68%), total phosphate (TP) (82%), biological oxygen demand (BOD) (86%) and chemical oxygen demand (COD) (89%) from wastewater. The present data indicate that this excellent microalga can be used in mixotrophic cultivation for wastewater purification coupled with commercial production of valued biomass and high-quality algal oils.


Assuntos
Compostos de Amônio , Microalgas , Scenedesmus , Purificação da Água , Acetatos , Biocombustíveis , Biomassa , Ácidos Graxos Monoinsaturados , Óleos , Águas Residuárias
10.
Chemosphere ; 283: 131196, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34146883

RESUMO

Cadmium (Cd) is a non-biodegradable pollutant that has become a global threat due to its bioaccumulation and biomagnification in higher trophic levels of the food chain. Green technologies such as phycoremediation is an emerging approach and possess edge over conventional methods to remediate Cd from the environment. The present investigation elucidates the adaptive mechanism of a freshwater microalga, Scenedesmus sp. IITRIND2 under Cd stress. The microalga showed excellent tolerance to Cd stress with IC50 value of ~32 ppm. The microalga showed phenomenal removal efficiency (~80%) when exposed to 25 ppm of Cd. Such a high uptake of Cd by the cells was accompanied with increased total lipid content (~33% of dry cell weight). Additionally, the elevated level of ROS, lipid peroxidation, glycine-betaine, and antioxidant enzymes evidenced the activation of efficient antioxidant machinery for alleviating the Cd stress. Further, analysis of the fatty acid methyl ester (FAME) presented a steady increase in saturated and polyunsaturated fatty acids with biodiesel properties complying the American and European fuel standards. The study proposes an integrated approach for bioremediation of toxic Cd using hyper-tolerant microalgal strains along with biodiesel production from the generated algal biomass.


Assuntos
Microalgas , Scenedesmus , Biodegradação Ambiental , Biocombustíveis , Biomassa , Cádmio/toxicidade , Ácidos Graxos
11.
Sci Total Environ ; 792: 148428, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34147802

RESUMO

The combination of lactic acid production wastewater and oil-producing microalgal culture could not only achieve harmless treatment of wastewater but also provided nutrients and significant amounts of water for microalgal culture. Thus the effects of different nutrients on the biomass yield, lipid yield of Scenedesmus dimorphus with lactic acid wastewater were investigated. Although lactic acid wastewater was very suitable for the cultivation of oil-producing microalgae, some nutrients were still needed. So 0.79 g/L NaNO3, 14 mg/L MgSO4·7H2O, 4 mg/L K2HPO4·3H2O, and trace elements needed to be added in the microalgal culture with lactic acid wastewater. In the optimized wastewater medium, the lipid yield could reach 1.54 ± 0.04 g/L, which was 48.1% higher than the level of 1.04 ± 0.06 g/L in the BG11 medium. Microalgae cells had high absorption capacity for nitrogen and phosphorus. The nitrogen, phosphorus removal rate of wastewater reached 96.31% and 90.78%, respectively, after 10 days of culture. And the treated wastewater could be used for lactic acid production for four times. These investigations laid a foundation for reducing the pollution of lactic acid wastewater, exploring a late-model for oleaginous microalgae cleaner production.


Assuntos
Microalgas , Scenedesmus , Biocombustíveis , Biomassa , Análise Custo-Benefício , Ácido Láctico , Nitrogênio , Fósforo , Águas Residuárias
12.
J Hazard Mater ; 418: 126354, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34130160

RESUMO

The continuous release of manufactured nanomaterials (MNMs) to environments raised concerns on their combined toxicological risks with co-existing contaminants, since MNMs might severely alter the environmental behavior and fate of the contaminants. In this study, the combined toxicity of nano-sized titanium dioxide (nTiO2) and cadmium (Cd2+) to the green alga Scenedesmus obliquus and the underlying physicochemical mechanisms were investigated for the first time at different concentration ratios of Cd2+ to nTiO2 to closely mimic the realistic environment scenarios where the concentration ratios of nTiO2 to other contaminants are constantly changing. Our results suggested that under the co-exposure to different concentration ratios of Cd2+ to nTiO2, the co-exposure contaminants exhibited three different combined toxicity modes (antagonistic, partially additive, and synergistic). Specifically, antagonistic combined toxicity was observed under co-exposure to a low concentration ratio of nTiO2 to Cd2+ as the absorption by nTiO2 decreased the bioavailability of Cd2+. However, the partially additive and synergistic combined toxicity occurred when the proportion of nTiO2 in the co-exposure system was relatively high, which would mechanically and/or oxidatively damage the alga cell structures. Even worse, as a carrier of Cd2+, nTiO2 enhanced the amount of Cd2+ entering cells, which significantly enhanced the toxicity of Cd2+ to algae. Overall, we demonstrated that concentration ratios of nTiO2 to Cd2+ play an important role in determining the combined toxicity mode, which would provide a novel reference to environmental and health risk assessment of co-exposure to conventional pollutants and MNMs.


Assuntos
Nanopartículas , Scenedesmus , Poluentes Químicos da Água , Cádmio/toxicidade , Titânio/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
13.
Environ Res ; 201: 111499, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34146525

RESUMO

The current research focuses on the Intracellular biosynthesis of Ag/AgCl nanohybrids in microalgae, Scenedesmus sp. The effect of biosynthesis process on growth and lipid profile of cells is key element of this study. Ag/AgCl nanohybrids synthesized intracellularly were characterized by UV-Vis spectrophotometer, Powder X-Ray Diffraction (P-XRD), Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HRTEM). 10-20 nm and 10-50 nm sized spherical shaped nanoparticles of polycrystalline nature were grown using 0.5 and 1 mM of AgNO3 precursor, respectively and Scenedesmus sp. as reducing agent. Total lipid content of the cells treated with 0.5 mM and 1 mM AgNO3 was static and found to be 43.2 ± 0.01 µg/mL and 48.2 ± 0.02 µg/mL respectively at 120 h of Ag/AgCl nanoparticles biosynthesis. FAME (Fatty Acid Methyl Ester) profile was improved due to intracellular nanoparticles biosynthesis with maximum C16:0 (palmitic acid) (35.7%) in cells treated with 0.5 mM AgNO3 used for Ag/AgCl nanohybrids synthesis. Palmitic acid in cells exposed to 0.5 mM concentration of metallic precursor increased by 75.86%. Synthesized nanoparticles were tested on four bacterial strains to establish its antibacterial efficiency showing appropriate zone of inhibition at varying concentrations. Present study efficiently demonstrates the utility of microalgae integrating nanoparticles biosynthesis and lipid accumulation.


Assuntos
Nanopartículas Metálicas , Scenedesmus , Antibacterianos/farmacologia , Lipídeos , Prata
14.
Biotechnol J ; 16(8): e2100067, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34008305

RESUMO

BACKGROUND: Current production costs of microalgal biomass indicate that only highly-productive cultivation facilities will approach commercial feasibility. Geographical site selection for siting those facilities is critical for achieving target productivities. The aim of this study was to provide a semi-empirical estimation of microalgal biomass and lipids productivity in South America. METHODS AND RESULTS: Simulated-climate was programed in environmental photobioreactors (Phenometrics) for a simulation of cultivation in open raceway ponds at different geographical sites. The mean annual South American biomass productivity of 20-cm deep ponds was 12 ± 4 g · m- 2 · d-1 . The most productive regions were clustered in the subtropical and tropical regions of the continent. Fortaleza (Brazil) showed a low seasonality and a high annual mean productivity of 23 g · m-2 · d-1 in 5-cm deep ponds, closely approaching the productivity target. Lipids accumulation and productivity in Fortaleza showed a high microalgal oil accumulation up to 46% (w/w) and a maximum oil productivity of 5 g · m-2 · d-1 for biomass containing around 20% lipids (w/w). CONCLUSION: This study provides the first semi-empirical estimation of microalgal productivity in South America and supports a high potential of a vast region of the continent.


Assuntos
Microalgas , Scenedesmus , Biocombustíveis , Biomassa , Lipídeos , Fotobiorreatores
15.
Environ Sci Pollut Res Int ; 28(31): 42547-42561, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33813694

RESUMO

Three species of freshwater planktonic green microalgae: Ankistrodesmus braunii, Ankistrodesmus falcatus, and Scenedesmus incrassatulus, were isolated from the Nile water in Upper Egypt. These microalgae were exposed to nutritional (nitrogen, phosphorus, and iron) limitations and salinity stress to study their effects on the algal growth and to elevate the lipid content within their cells. The results indicated that exposure to these conditions had a significant impact on the algal growth. The lipid content of the studied algae increased as a result of the salinity stress. The highest lipid content was recorded in A. braunii culture treated with 50 mM NaCl (34.4% of dry weight) and S. incrassatulus cultures treated with 100 mM NaCl (37.7% of dry weight) on the 6th day of cultivation, while the culture of A. falcatus treated with 100 mM NaCl recorded the maximum lipid content (53% of dry weight) on the 10th day of the experiment. The biodiesel quality parameters of the fatty acid methyl ester profile of S. incrassatulus appeared to be in agreement with the international criteria. S. incrassatulus could be regarded as a quite promising feedstock for the biodiesel production.


Assuntos
Microalgas , Scenedesmus , Biocombustíveis , Biomassa , Lipídeos , Fósforo
16.
J Sci Food Agric ; 101(13): 5508-5519, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33682135

RESUMO

BACKGROUND: The three-phase extraction process of olive oil produces highly contaminated wastewater (OMW). The elimination of this toxic by-product is an important environmental issue that requires the development of an appropriate management solution. The cultivation of microalgae using OMW as growth medium was therefore studied using single (the culture medium was formed by 0% to 80% ultrafiltered olive mill wastewater (OMUF) or OMW added to BG11) and two-stage strategies (microalgae were firstly cultivated in the BG11 medium. In the second stage, 40% and 80% of OMUF and OMW were added to the culture). In this work, biodegradation of OMW and subsequent extraction of lipid and antioxidant molecules was investigated as an ecofriendly method for the bioremediation and valorization of OMW. RESULTS: For two-stage cultivation, OMUF and OMW stress enhanced the intracellular amount of polyphenol accumulated in Scenedesmus sp. and exhibited the highest 2, 2-diphenyl-1- picrylhydrazyl radical (DPPH) and 2,2'-azino-bis (3-ethylbenzoline-6-sulfonate) radical (ABTS) scavenging ability compared with single-stage cultivation. Moreover, the lipid profile is dominated by polyunsaturated acids. In the single-stage cultivation, the Ch a, Ch b, carotenoid, carbohydrate and lipid content of 2.57, 7.4, 1.69, 368, and 644 g kg-1 were observed in 40% OMUF added culture, respectively, along with high biomass productivity and 58% of polyphenol removal. Moreover, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that the biomass of Scenedesmus sp. cultured on 40% OMUF did not show any toxic effect, making it an efficient strategy. CONCLUSION: The results indicate that Scenedesmus sp. is a promising microalga for the biotreatment of OMW and the extraction of bioactive metabolites. © 2021 Society of Chemical Industry.


Assuntos
Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Polifenóis/metabolismo , Scenedesmus/crescimento & desenvolvimento , Scenedesmus/metabolismo , Águas Residuárias/análise , Biodegradação Ambiental , Manipulação de Alimentos , Microalgas/química , Azeite de Oliva/química , Polifenóis/análise , Scenedesmus/química , Resíduos/análise
17.
Commun Biol ; 4(1): 333, 2021 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-33712730

RESUMO

Microalgae efficiently convert sunlight into lipids and carbohydrates, offering bio-based alternatives for energy and chemical production. Improving algal productivity and robustness against abiotic stress requires a systems level characterization enabled by functional genomics. Here, we characterize a halotolerant microalga Scenedesmus sp. NREL 46B-D3 demonstrating peak growth near 25 °C that reaches 30 g/m2/day and the highest biomass accumulation capacity post cell division reported to date for a halotolerant strain. Functional genomics analysis revealed that genes involved in lipid production, ion channels and antiporters are expanded and expressed. Exposure to temperature stress shifts fatty acid metabolism and increases amino acids synthesis. Co-expression analysis shows that many fatty acid biosynthesis genes are overexpressed with specific transcription factors under cold stress. These and other genes involved in the metabolic and regulatory response to temperature stress can be further explored for strain improvement.


Assuntos
Metabolismo Energético/genética , Perfilação da Expressão Gênica , Genoma , Metabolômica , Microalgas/genética , Scenedesmus/genética , Temperatura , Aminoácidos/biossíntese , Antiporters/genética , Antiporters/metabolismo , Biomassa , Ácidos Graxos/biossíntese , Regulação da Expressão Gênica , Canais Iônicos/genética , Canais Iônicos/metabolismo , Lipogênese/genética , Metaboloma , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Tolerância ao Sal , Scenedesmus/crescimento & desenvolvimento , Scenedesmus/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcriptoma
18.
Sci Total Environ ; 778: 146262, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33714809

RESUMO

Environmental concerns due to fossil fuel usage has turned the research interest towards biomass and bioenergy field. Renewable biomass such as microalgae provides numerous advantages as they can grow in wastewater; sequester carbon dioxide, economical and eco-friendly. In this study, effect of pretreatment of microalgae (Scenedesmus obliquus) biomass using post-hydrothermal liquefaction wastewater (PHWW) for bio-oil production through hydrothermal liquefaction at a temperature of 300 °C was studied. Results showed liquefaction of pre-treated biomass yielded 48.53% bio-oil whereas 28.35% was resulted from biomass without pretreatment. The analysis of higher heating value of bio-oil showed that pretreated biomass oil has 36.19 MJ.Kg-1 against non-pretreated biomass oil, which has 28.88 MJ.Kg-1. Bio-oil (pretreated biomass) analysis revealed that 60% of compounds are in diesel and gasoline range with 58.09% of energy recovery. Bio-oil was rich in hydrocarbons of C7-C21 range with less oxygenated compounds. Carbon balance showed that an increase of 13% of carbon was sequestered in solid residue obtained from pretreated biomass and about 146% of increase also obtained in bio-oil.


Assuntos
Microalgas , Scenedesmus , Biocombustíveis , Biomassa , Carvão Vegetal , Óleos Vegetais , Polifenóis , Temperatura , Água
19.
Chemosphere ; 275: 130125, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33677276

RESUMO

Microalgal biofilm has been recognized as a cost-effective biorsorbent for heavy metal and a promising method for microalgae-water separation. In this study, living suspended Scenedesmus obliquus FACHB-12 (isolated from southern China) and its biofilm with different carriers were investigated to remove cadmium from aqueous solution. S. obliquus FACHB-12 biofilm with luffa sponge carrier showed highest cadmium removal efficiency at 92.7% compared to biofilm with K3 carrier (75.3%) and significantly higher than suspended S. obliquus FACHB-12 (61.8%) in 2 h experiment with initial Cd2+ concentration at 3.0 mg/L at pH = 6.0 with 0.8 g/L of biomass under room temperature. S. obliquus FACHB-12 biofilm with K3 and luffa sponge carrier also demonstrated higher tolerance towards increased Cd2+ concentration with highest biosorption efficiency at 85.1% and 90.35% respectively under 20 mg/L of Cd2+, while suspended S. obliquus FACHB-12 biosorption efficiency achieved 81.4% under 10 mg/L of Cd2+ and started to decline over increased cadmium concentration. The adsorption kinetics for all experimental groups followed the pseudo-second-order adsorption model, with biosorption equilibrium favored in Langmuir isotherm. The maximum biosorption capacity estimated by Langmuir isotherm reached 133.14 mg/g biomass in S. obliquus FACHB-12 biofilm with luffa sponge carrier, followed by 78.76 mg/g with K3 carrier, and 60.03 mg/g with suspended S. obliquus FACHB-12. Results suggest an efficient, inexpensive microalgal biofilm with biological carrier system could enhance high cadmium removal for advanced wastewater treatment and provide a cost-effective method for microalgae harvesting process.


Assuntos
Scenedesmus , Poluentes Químicos da Água , Adsorção , Biofilmes , Biomassa , Cádmio , China , Estudos de Viabilidade , Concentração de Íons de Hidrogênio , Cinética , Poluentes Químicos da Água/análise
20.
Sci Total Environ ; 771: 144700, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33736139

RESUMO

The present study has tested the biodiesel potential of two hyper lipid producing strains Chlorella sp. and Scenedesmus sp. in terms of biomass yield, quantity and quality of lipid and fatty acid composition. Biomass yield of Chlorella sp. and Scenedesmus sp. was 1.26 and 1.33 g/L, respectively on day 18 and 20. The lipid content and lipid productivity of Chlorella sp. and Scenedesmus sp. was estimated to be 21.3, 26.5% and 12.33, 14.74 mg/L/d, respectively. Notably, relative abundance of lipid types in both the strains revealed >60% neutral lipids followed by glycolipids and phospholipids in minimal level. Central composite design based optimization revealed 69 and 65.4% FAME yield from Chlorella sp. and Scenedesmus sp. at 3% sulphuric acid and 65 °C reaction temperature. Eventually, higher levels of saturated fatty acids (~45%) and monounsaturated fatty acids (~34%) and make Scenedesmus sp. a promising parent material for workable biodiesel production.


Assuntos
Chlorella , Microalgas , Scenedesmus , Biocombustíveis , Biomassa , Ésteres , Ácidos Graxos , Lipídeos
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