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1.
Chemosphere ; 238: 124576, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31421462

RESUMO

This study assesses and compares the influence of silver nanoparticles (AgNPs) and silver nitrate (AgNO3) on the fatty acid composition, pigments, and growth indices of Chlorella vulgaris. Toxicity testing was carried at the estimated and/or above predicted environmental concentrations of AgNPs and AgNO3. AgNO3 treatments impaired the population growth of C. vulgaris about 2-183 times more than the respective AgNPs ones. The pigments displayed a concentration-dependent decrease in response to both forms of silver; however, AgNO3 displayed higher severity to the pigments than AgNPs. In exposure to 10 µg L-1 AgNO3, the contents of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid, respectively, demonstrated a reduction of about 5, 3, 4, and 4 times when compared with the same respective concentration of AgNPs. Total amounts of saturated (∑SFA), monounsaturated (∑MUFA), and polyunsaturated (∑PUFA) fatty acids as well as the ratio of unsaturated to saturated ones (Unsat./Sat.) displayed somewhat similar-concentration responses. ∑SFA exhibited a hormesis response, and ∑MUFA, ∑PUFA, and Unsat./Sat. did a decreasing trend with increasing concentration of AgNPs and AgNO3. Myristoleic acid, nervonic acid, and eicosadienoic acid revealed the highest sensitivity. Pearson analysis illustrated the highest correlation among myristoleic acid, eicosenoic acid, and nervonic acid as well as among palmitic acid, stearic acid, palmitoleic acid, and oleic acid. Taken together, AgNPs and the released ions could disrupt physiological health state of microalgae through perturbation in the fatty acid composition (especially MUFAs and PUFAs) and other macromolecules. These types of bioperturbations could change the good health state of aquatic ecosystems.


Assuntos
Chlorella vulgaris/crescimento & desenvolvimento , Poluentes Ambientais/toxicidade , Ácidos Graxos/metabolismo , Nanopartículas Metálicas/toxicidade , Nitrato de Prata/toxicidade , Prata/toxicidade , Carotenoides/metabolismo , Chlorella vulgaris/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Ecossistema , Ecotoxicologia , Ácidos Graxos Monoinsaturados/metabolismo , Microalgas/efeitos dos fármacos , Testes de Toxicidade
2.
Ecotoxicol Environ Saf ; 186: 109762, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31629189

RESUMO

The use of algae is an effective approach to remove phenol and its derivatives from polluted water. The growth behavior, glucose consumption and phenol removal efficiency of Chlorella vulgaris under the synergistic effects of glucose and phenol were investigated. The evolutions of tolerance and removal efficiency of C. vulgaris to phenol under different trophic modes and glucose contents were observed. The results revealed that growth of C. vulgaris were inhibited with the increase of phenol from 0 to 400 mg L-1 in culture media; the tolerance to phenol enhanced with the addition of glucose from 2 to 10 g L-1, while glucose consumption was inhibited with the increase of phenol content; phenol removal efficiency varied with glucose concentrations in mixotrophic media. The finding suggested that phenol inhibited the growth of C. vulgaris and glucose assimilation under mixotrophic cultivation, while appropriate glucose addition could enhance the tolerance of C. vulgaris to phenol and affect the phenol removal efficiency.


Assuntos
Chlorella vulgaris/crescimento & desenvolvimento , Glucose/farmacologia , Fenol/análise , Poluentes da Água/análise , Biodegradação Ambiental , Biomassa , Chlorella vulgaris/metabolismo , Meios de Cultura/química , Relação Dose-Resposta a Droga , Glucose/metabolismo , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Fenol/metabolismo , Fenol/toxicidade , Poluentes da Água/metabolismo , Poluentes da Água/toxicidade
3.
Environ Monit Assess ; 191(11): 679, 2019 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-31655913

RESUMO

Algal treatment methods have been widely used in nutrient removal studies. However, in most cases, the experimental conditions have not been fully complied with actual conditions. For instance, the effect of algae acclimation to wastewater medium on cell growth and removal efficiency has generally been ignored in laboratory scale experiments. This paper investigates the effect of acclimation on cell growth and nutrient uptake rates of Arthrospira platensis and Chlorella vulgaris. For this purpose, batch reactors, which contained the synthetic secondary effluent, had been inoculated by acclimated algae cells and the growth parameters were measured daily, as well as nutrient concentration. A significant decrease (P < 0.05) in chlorophyll-a content of acclimated A. platensis was observed, although there was no significant change in specific growth rate (µ) and doubling time (dt), in comparison with the non-acclimated ones. Moreover, the acclimation process changed the chlorophyll-a content and kinetic parameters of Chlorella vulgaris. Furthermore, t test results showed a significant increase in removal rate of nitrogen compounds through the acclimation. Residence time of A. platensis and C. vulgaris was also reduced through the acclimation by approximately 50% and 25%, respectively.


Assuntos
Chlorella vulgaris/fisiologia , Eliminação de Resíduos Líquidos/métodos , Aclimatação , Chlorella vulgaris/crescimento & desenvolvimento , Clorofila/análogos & derivados , Monitoramento Ambiental , Cinética , Nitrogênio/análise , Nutrientes , Fósforo/análise , Spirulina/fisiologia , Águas Residuárias
4.
Appl Microbiol Biotechnol ; 103(19): 8255-8265, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31396677

RESUMO

Coupling algal cultivation with wastewater treatment due to their potentials to alleviate energy crisis and reduce environmental burden has attracted the increased attention in recent years. However, these microalgal-based processes are challenging since daily and seasonal temperature fluctuation may affect microalgal growth in wastewater, and the effects of the temperature regimes on microalgal biomass production and wastewater nutrient removal remain unclear. In this study, Chlorella vulgaris was continuously cultured for 15 days in municipal wastewater to investigate the effects on the algal biomass and wastewater nutrient removal in three temperature regimes: (1) low temperature (4 °C), (2) high temperature (35 °C), and (3) alternating high-low temperature (35 °C in the day: 4 °C at night). Compared with the other two temperature regimes, the high-low temperature conditions generated the most biomass (1.62 g L-1), the highest biomass production rate (99.21 mg L-1 day-1), and most efficient removal of COD, TN, NH3-N, and TP (83.0%, 96.5%, 97.8%, and 99.2%, respectively). In addition, the polysaccharides, proteins, lipid content, and fatty acid methyl ester composition analysis indicates that in alternating high-low temperature condition, biomass production increased the potential for biofuel production, and there was the highest lipid content (26.4% of total dry biomass). The results showed that the nutrients except COD were all efficiently removed in these temperature conditions, and the alternating high-low temperature condition showed great potential to generate algal biomass and alleviate the wastewater nutrients. This study provides some valuable information for large-scale algal cultivation in wastewater and microalgal-based wastewater treatments.


Assuntos
Chlorella vulgaris/crescimento & desenvolvimento , Chlorella vulgaris/efeitos da radiação , Compostos Orgânicos/metabolismo , Temperatura Ambiente , Águas Residuárias/microbiologia , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos , Biomassa , Lipídeos/análise , Polissacarídeos/análise , Proteínas/análise , Águas Residuárias/química
5.
Environ Sci Pollut Res Int ; 26(28): 29473-29489, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31396874

RESUMO

Treatment of wastewater by using of microalgae is a cost-effective system. Chlorella sorokiniana pa.91 and Chlorella vulgaris were studied in this research. Chlorella sorokiniana pa.91 was isolated from the dairy wastewater. In this study, treated wastewaters in preliminary and secondary treatment units of dairy wastewater treatment plant were used as medium. Maximum growth of two species of microalgae was examined in these two mediums, and also, nutrient removal was studied. The performance of two species of microalgae was studied on laboratory scale at different temperatures and light intensities. The best observed temperatures for Chlorella vulgaris and Chlorella sorokiniana pa.91 were 25 and 28 °C, respectively, and the best observed performance for them was obtained at 7500 lx. The values of specific growth rate and biomass productivity in effluent of preliminary treatment unit for Chlorella vulgaris were 0.331 day-1 and 0.214 g L-l day-1, respectively, and for Chlorella sorokiniana pa.91 were 0.375 day-1 and 0.233 g L-l day-1, respectively. Also, these parameters for Chlorella vulgaris in effluent of secondary treatment unit were determined 0.359 day-1 and 0.166 g L-l day-1, respectively, and for Chlorella sorokiniana pa.91 were obtained 0.422 day-1 and 0.185 g L-l day-1, respectively. The removal efficiency of nitrate, ammonia, phosphate, and chemical oxygen demand for Chlorella sorokiniana pa.91 and Chlorella vulgaris in both of effluents was more than 80%. Based on the results, effluent of treatment plants can be a suitable microalgae growth medium, and the microalgae can be used as effective post treatment system.


Assuntos
Chlorella vulgaris/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Nitratos/química , Fosfatos/química , Amônia , Análise da Demanda Biológica de Oxigênio , Biomassa , Águas Residuárias
6.
J Agric Food Chem ; 67(31): 8668-8676, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31271028

RESUMO

This study investigated the effect of Chlorella vulgaris (C. vulgaris) on genotoxicity, cytotoxicity, and apoptosis in Caco-2 and HT-29 cells. C. vulgaris significantly induced DNA damage in both cell lines at a concentration of 200 µg dry matter/mL (comet tail intensity CTI: 24.6 ± 4.7% for Caco-2, 16.6 ± 0.9% for HT-29). The application of processing (sonication, ball-milling) did not affect the genotoxicity negatively and lowered the lipid peroxidation in C. vulgaris preparations. C. vulgaris-induced intracellular formation of reactive oxygen species in human cell lines and might be responsible for the genotoxic effect. A solid fraction mainly triggered the observed DNA damage (CTI: 41.5 ± 1.9%), whereas a hydrophilic (CTI: 7.9 ± 1.7%) and lipophilic (CTI: 10.2 ± 2.1%) fraction revealed a significantly lower tail intensity. C. vulgaris significantly induced DNA damage in both cell lines possibly through intracellular formation of reactive oxygen species; however, it was repaired after a 2 h recovery time or was even avoided at lower concentrations. In addition, none of the preparations indicated an adverse effect on cell proliferation or revealed apoptotic activity.


Assuntos
Chlorella vulgaris/química , Dano ao DNA/efeitos dos fármacos , Células Epiteliais/citologia , Mutagênicos/toxicidade , Extratos Vegetais/toxicidade , Apoptose/efeitos dos fármacos , Processos Autotróficos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Chlorella vulgaris/crescimento & desenvolvimento , Chlorella vulgaris/efeitos da radiação , Ensaio Cometa , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Humanos , Luz , Peroxidação de Lipídeos/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
7.
Environ Toxicol Pharmacol ; 70: 103208, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207443

RESUMO

Boron (B) has been widely used and contaminated the aquatic ecosystem. However, knowledge of the effects of sodium pentaborate pentahydrate (SPP) on algae remains limited. This study aimed to assess SPP toxicity using multiple endpoints, specially detecting the intracellular metal ion concentrations, malondialdehyde (MDA) content and extracellular polymeric substance (EPS) classes for the very first time during SPP exposure to Chlorella vulgaris (C. vulgaris). Our findings indicated that the inhibitory effects of SPP on C. vulgaris may be related to nutrient absorption and utilization. The changes in intracellular starch grains, MDA and the protein-like substances in EPS probably acted as a defense mechanism, helping to alleviate the toxic effects. This work may contribute to the understanding of the mechanism of SPP toxicity in algae. Further studies may focus on the effects of B on speciation of metallic ions and the interaction of B with metallic ions on aquatic organisms.


Assuntos
Boratos/toxicidade , Chlorella vulgaris/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Chlorella vulgaris/crescimento & desenvolvimento , Chlorella vulgaris/metabolismo , Chlorella vulgaris/ultraestrutura , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Malondialdeído/metabolismo , Microscopia Eletrônica de Transmissão
8.
Environ Sci Pollut Res Int ; 26(18): 18520-18532, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31049862

RESUMO

The present work investigated the potential of the green alga Chlorella vulgaris to produce high-quality biofuel under culture stress conditions. The cultivation was carried out in a 1000 l open plate tank system, which provides biomass yields comparable to open pond systems, but with less area needed. Algal biomass and lipid content were measured repeatedly. We compared the two solvent systems n-hexane and hexane/isopropanol (HIP) for extraction efficiency of lipids and applied three different extraction methods Soxhlet, soaking, and soaking followed by Soxhlet (soak-Sox). The combination of the HIP solvent and the soak-Sox provided the highest lipid yield (15.8 ± 0.174). Volumetric biomass and lipid productivity were 0.201 g l-1 day-1 and 31.71 mg l-1 day-1, respectively, whereas areal biomass and lipid productivity were 25.73 g m-2 day-1 and 4.066 g m-2 day-1, respectively. The fatty acid profile by means of gas chromatography resulted in seven fatty acids from C12 to C18. The most abundant fatty acid methyl esters (FAMES) were palmitic (C16:0), oleic (C18:1), and stearic (C18:0) acids. Lipid synthesis enhanced by optimizing the Kuhl growth medium with replacing nitrate by urea (50% N compared to the original recipe) increased salt content (10 g/l NaCl), ferrous sulfate (0.5 g/l), and sodium acetate addition (1 g/l). With regard to density, kinematic viscosity, gravity, pour point, flash point, and cetane number, the Chlorella-biodiesel comply with ASTM and EN standards thus pointing at the high potential of lipids synthesized by Chlorella as a feedstock for biodiesel production.


Assuntos
Biocombustíveis/análise , Biotecnologia/métodos , Chlorella vulgaris/crescimento & desenvolvimento , Ácidos Graxos/análise , Microalgas/crescimento & desenvolvimento , Biomassa , Biotecnologia/instrumentação , Chlorella vulgaris/metabolismo , Meios de Cultura/química , Microalgas/metabolismo
9.
Sci Total Environ ; 676: 356-367, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31048166

RESUMO

Nejayote and swine wastewater are highly pollutant effluents and a source of organic matter load that sometimes released into water bodies (rivers or lakes), soils or public sewer system, with or without partial treatments. Nejayote is a wastewater product of alkaline cooking of maize, whereas, swine wastewater results from the primary production of pigs for the meat market. Owing to the presence of environmentally related pollutants, both sources are considered the major cause of pollution and thus require urgent action. Herein, we report a synergistic approach to effectively use and/or treat Nejayote and swine wastewater as a cost-effective culture medium for microalgae growth, which ultimately induces the removal of polluting agents. In this study, the strains Arthrospira maxima and Chlorella vulgaris were grown using different dilutions of Nejayote and swine wastewater. Both wastewaters were used as the only source of macronutrients and trace elements for growth. For A. maxima, the treatment of 10% nejayote and 90% of water (T3) resulted in a cell growth of 32 × 104 cell/mL at 12 days (µmax = 0.27/d). While, a mixture of 25% swine wastewater, 25% nejayote and 50% water (T2) produced 32 × 104 cell/mL at 18 days (µmax = 0.16/d). A significant reduction was also noted as 92% from 138 mg/L of TN, 75% from 77 mg/L of TP, and 96% from 8903 mg/L of COD, among different treatments. For C. vulgaris, the treatment of 10% swine wastewater and 90% water (T1) gave a cell growth of 128 × 106 cell/mL (µmax = 0.57/d) followed by T3 yielded 62 × 106 cell/mL (µmax = 0.70/d) and T2 yielded 48 × 106 cell/mL (µmax = 0.54/d). Up to 91% reduction from 138 mg/L of TN, 85% from 19 mg/L of TP and 96% from 4870 mg/L of COD was also recorded. These results show that microalgae can be used to treat these types of wastewater while at the same time using them as a culture media for microalgae. The resultant biomass can additionally be used for getting other sub-products of commercial interest.


Assuntos
Chlorella vulgaris/crescimento & desenvolvimento , Spirulina/crescimento & desenvolvimento , Eliminação de Resíduos Líquidos , Águas Residuárias/microbiologia , Criação de Animais Domésticos , Animais
10.
Bioprocess Biosyst Eng ; 42(9): 1517-1526, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31111212

RESUMO

In this study, Pavlova lutheri, Chlorella vulgaris, and Porphyridium cruentum were cultured using modified F/2 media in a 1 L flask culture. Various nitrate concentrations were tested to determine an optimal nitrate concentration for algal growth. Subsequently, the effect of light emitted at a specific wavelength on biomass and lipid production by three microalgae was evaluated using various wavelengths of light-emitting diodes (LED). Biomass production by P. lutheri, C. vulgaris, and P. cruentum were the highest with blue, red, and green LED wavelength with 1.09 g dcw/L, 1.23 g dcw/L, and 1.28 g dcw/L on day 14, respectively. Biomass production was highest at the complementary LED wavelength to the color of microalgae. Lipid production by P. lutheri, C. vulgaris, and P. cruentum were the highest with yellow, green, and red LEDs' wavelength, respectively. Eicosapentaenoic acid production by P. lutheri, C. vulgaris, and P. cruentum was 10.35%, 10.14%, and 14.61%, and those of docosahexaenoic acid were 6.09%, 8.95%, and 11.29%, respectively.


Assuntos
Chlorella vulgaris/crescimento & desenvolvimento , Ácidos Graxos Insaturados/biossíntese , Haptófitas/crescimento & desenvolvimento , Luz , Iluminação , Microalgas/crescimento & desenvolvimento , Porphyridium/crescimento & desenvolvimento , Técnicas de Cultura de Células
11.
Environ Pollut ; 250: 610-617, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31035143

RESUMO

Enantiomers of chiral pesticides usually display different toxic effects on non-target organisms in surrounding environment, but there are few studies on its enantioselective toxicity of paclobutrazol to aquatic organisms such as Chlorella vulgaris (C. vulgaris). In this study, the enantioselective bioaccumulation and toxicities, such as acute toxicity and oxidative stress, of the racemate, (2S, 3S)-enantiomer (S-enantiomer) and (2R, 3R)-enantiomer (R-enantiomer) of paclobutrazol to the C. vulgaris cells were investigated. The results showed that the algae cells were able to accumulate the paclobutrazol in a short time, while this bioaccumulation had no enantioselective distinction between the two enantiomers during biological metabolism. However, the racemate and two enantiomers of paclobutrazol significantly inhibited the growth of C. vulgaris, displayed different median lethal concentrations. The photosynthetic pigments, photosynthesis-related genes as well as antioxidation-related biomarkers in treated C. vulgaris were also investigated. In general, R-enantiomer was found to be more toxic to C. vulgaris cells than its racemate and S-enantiomer. Additionally, transmission electron microscopy (TEM) analysis showed the R-enantiomer caused more serious changes than S-enantiomer. Moreover, contents of two plant hormones (gibberellin, GA and indoleacetic acid, IAA) were determined in treated C. vulgaris. Higher paclobutrazol concentrations caused lower IAA contents significantly. Nevertheless, the two enantiomers showed no enantioselective effects on the biosynthesis of GA in C. vulgaris. Our results are helpful to understand the enantioselective effects of paclobutrazol enantiomers on non-target organisms, and useful for evaluating their environmental risks.


Assuntos
Chlorella vulgaris/efeitos dos fármacos , Inibidores do Crescimento/toxicidade , Praguicidas/toxicidade , Triazóis/toxicidade , Antioxidantes/metabolismo , Chlorella vulgaris/crescimento & desenvolvimento , Chlorella vulgaris/metabolismo , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos , Estereoisomerismo , Triazóis/química
12.
Chemosphere ; 224: 93-102, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30818199

RESUMO

In their environments, aquatic organisms are simultaneously exposed to mixtures of several endocrine disrupting compounds, including hormones. However, most of the toxicity studies so far focused on effects of single contaminants. The available information on the potential toxicity of combined hormones on microalgae is extremely limited. For these reasons the aim of this study was to evaluate the individual and mixture effect of estrone (E1), ß-estradiol (E2), estriol (E3), 17-α-ethinylestradiol (EE2), progesterone (PRO), 5-pregnen-3ß-ol-20-one (PRE), levonorgestrel (LG) and testosterone (TST) on Chlorella vulgaris and Scenedesmus armatus. Green algae cells were exposed to different concentrations (0.1-100 mg L-1) of hormones for 14 days. Biomass in the form of dry weight and chlorophyll a was examined. The decreasing order of toxicity (based on EC50, 14d) to Chlorella vulgaris and Scenedesmus armatus was: EE2>PRO > E2>PRE > TST > E3>LG > E1 and EE2>PRO > TST > E2>PRE > LG > E1>E3, respectively. Chlorella vulgaris was more sensitive to the effects of hormones than Scenedesmus armatus. Although mixed hormones were more toxic to green algae than single hormones, in the ecosystem mixtures can pose higher ecological risk than single pollutants. Therefore, data on the toxicology of both single and mixed hormones is very valuable for assessment of the possibility of adverse ecological effects caused by these pollutants. Furthermore, these results suggest that environmental exposure to hormone mixtures may cause toxicity levels different to the sum of those of the single hormones and provides a basic understanding of their toxic effect on algae.


Assuntos
Clorófitas/efeitos dos fármacos , Misturas Complexas/toxicidade , Hormônios/toxicidade , Chlorella vulgaris/efeitos dos fármacos , Chlorella vulgaris/crescimento & desenvolvimento , Clorófitas/crescimento & desenvolvimento , Disruptores Endócrinos/toxicidade , Microalgas/efeitos dos fármacos , Scenedesmus/efeitos dos fármacos , Scenedesmus/crescimento & desenvolvimento , Poluentes Químicos da Água/farmacologia
13.
Ecotoxicol Environ Saf ; 174: 43-47, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30818259

RESUMO

Tetracycline antibiotics are the most widely used antibiotics in the world and the most common veterinary drugs and feed additives used in livestock, poultry and aquaculture operations. Because antibiotics cannot be completely removed by currently existing sewage treatment facilities, these materials enter the environment directly via sewage treatment plant discharge, where they degrade. Accordingly, the metabolism and the ecological toxicity of tetracycline degradation products are worthy of attention. Herein, we investigated the effects of tetracycline and its degradation products (anhydrotetracycline and epitetracycline hydrochloride) on the growth, cell structure and algal cell oxidative stress of common Chlorella vulgaris. The results showed that the 96h-EC50 values of tetracycline (TC), anhydrotetracycline (ATC) and epitetracycline (ETC) on algal cells were 7.73, 5.96 and 8.42 mg/L, respectively. Moreover, the permeability of algal cells exposed to high concentrations of these three drugs was significantly enhanced. In addition, there were structural changes in the cells such as plasmolysis and starch granule deposition appeared, the thylakoid lamellae in the chloroplasts became blurred and deformed, and the vacuoles became larger. Exposure to higher concentrations (>5 mg/L) of TC and its degradation products ATC and ETC significantly upregulated the activity of ROS, as well as the antioxidants SOD and CAT. The levels of the lipid peroxidation product MDA also showed the same trend. Finally, ATC had the strongest toxicity toward algal cells, followed by TC and then ETC.


Assuntos
Antibacterianos/toxicidade , Chlorella vulgaris/efeitos dos fármacos , Tetraciclina/toxicidade , Antibacterianos/metabolismo , Antioxidantes/metabolismo , Chlorella vulgaris/crescimento & desenvolvimento , Chlorella vulgaris/metabolismo , Chlorella vulgaris/ultraestrutura , Água Doce , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo , Tetraciclina/metabolismo , Tetraciclinas/toxicidade
14.
Int. microbiol ; 22(1): 41-48, mar. 2019. graf, tab
Artigo em Inglês | IBECS | ID: ibc-184812

RESUMO

Microalgal-bacterial co-cultures were employed for the treatment of artificially prepared metal-rich wastewaters in this study. For the purpose, highly metal-resistant microalgal and bacterial species were isolated from a leading wastewater channel flowing through Lahore, Pakistan, and characterized at the molecular level. The microbial identities were proved after BLAST analysis. The microalgal (Chlorella vulgaris-BH1) and bacterial (Exiguobacterium profundum-BH2) species were then co-cultured in five different proportions. Five different proportions of potentially mutualistic microbial co-cultures (comprising of microalgal to bacterial cells in ratios of 1:3, 2:3, 3:3, 3:1, and 3:2) prepared thus were employed to remediate artificially prepared metal-loaded wastewaters. Three randomly selected toxic metals (Cu, Cr, and Ni) were used in this study to prepare metal-rich wastewaters. The microalgal-bacterial co-cultures were then exposed independently to the wastewaters containing 100 ppm of each of the above mentioned metals. The inoculated wastewaters were incubated maximally for a period of 15 days. The metal uptake was noted periodically after every 5 days. The results of the present study depicted that maximally about 78.7, 56.4, and 80% of Cu, Cr, and Ni were removed, respectively after an incubation period of 15 days. The microbial co-culture consisting of microalgal to bacterial cells in a ratio of 3:1 showed the highest remedial potential. The findings of the present study will be helpful in developing effective microalgal-bacterial consortia for economical, efficient, and environment-friendly rehabilitation of the polluted sites


No disponible


Assuntos
Bacillales/metabolismo , Chlorella vulgaris/metabolismo , Técnicas de Cocultura , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Bacillales/efeitos dos fármacos , Bacillales/crescimento & desenvolvimento , Chlorella vulgaris/efeitos dos fármacos , Chlorella vulgaris/crescimento & desenvolvimento , Poluentes Químicos da Água/toxicidade , Resistência a Medicamentos , Metais/toxicidade , Paquistão
15.
J Environ Sci (China) ; 79: 311-320, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30784454

RESUMO

Tracking the variation of the algogenic organic matter (AOM) released during the proliferation of green algae and subsequent treatment processes is crucial for constructing and optimizing control strategies. In this study, the potential of the spectroscopic tool was fully explored as a surrogate of AOM upon the cultivation of green algae and subsequent coagulation/flocculation (C/F) treatment processes using ZrCl4 and Al2(SO4)3. Fluorescence excitation emission matrix coupled with parallel factor analysis (EEM-PARAFAC) identified the presence of three independent fluorescent components in AOM, including protein-like (C1), fulvic-like (C2) and humic-like components (C3). Size exclusion chromatography (SEC) revealed that C1 in AOM was composed of large-sized proteins and aromatic amino acids. The individual components exhibited their unique characteristics with respect to the dynamic changes. C1 showed the highest correlation with AOM concentrations (R2 = 0.843) upon the C/F processes. C1 could also be suggested as an optical predictor for the formation of trihalomethanes upon the C/F processes. This study sheds a light for the potential application of the protein-like component (C1) as a practical surrogate to track the evolution of AOM in water treatment or wastewater reclamation systems involving Chlorella vulgaris green algae.


Assuntos
Compostos de Alúmen/química , Benzopiranos/química , Chlorella vulgaris/crescimento & desenvolvimento , Cloretos/química , Substâncias Húmicas , Proteínas de Plantas/química , Poluentes da Água/química , Zircônio/química , Floculação , Fluorescência , Espectrometria de Fluorescência , Purificação da Água/métodos
16.
Sci Total Environ ; 660: 1182-1190, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30743913

RESUMO

The effect of extracellular polymeric substances (EPS), vital organic matters and nutrient elements in the natural environment, on the behavior and toxicology of silver nanoparticles (AgNPs) and ions remains ambiguous. In this study, the role of EPS on the toxicity of AgNPs and dissolved silver ions (from AgNO3) to a green algae Chlorella vulgaris was investigated. After the removal of EPS, algae accumulated more silver, about 7.41- and 1.25-fold of those in the algae with EPS for AgNPs and AgNO3 treatments, respectively. The large amount of accumulated silver was bound to the algal cell surface for AgNPs treatment and was internalized in the algae for AgNO3 treatment, irrespective of the presence of EPS in algae. After exposure to AgNPs, the ruffles in the surfaces of algal cells were filled by AgNPs, and almost invisible. FTIR showed that for both AgNPs and AgNO3, the aldehyde groups on the cell surface were oxidized to carboxyl groups by silver ions, irrespective of the presence of EPS in algal cells, indicating that silver ions were released from the oxidization of AgNPs and reacted with algal cells. The content of chlorophyll showed that AgNPs depressed algal growth more remarkably than did AgNO3, independent of the presence of EPS in algae, suggesting that AgNPs had greater toxic effects on algae than did silver ions. The findings suggest that the barrier effect of EPS gave nanoparticles an extraordinary edge over ions, but EPS had no discerning effect on the interaction of algal cells with the silver ions released from AgNPs and AgNO3, and also on the effect of AgNPs and AgNO3 on algal growth.


Assuntos
Chlorella vulgaris/efeitos dos fármacos , Matriz Extracelular de Substâncias Poliméricas/química , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Chlorella vulgaris/crescimento & desenvolvimento , Chlorella vulgaris/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Poluentes Ambientais/toxicidade , Íons/toxicidade , Nanopartículas Metálicas/química , Oxirredução , Prata/química , Prata/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Int Microbiol ; 22(1): 41-48, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30810930

RESUMO

Microalgal-bacterial co-cultures were employed for the treatment of artificially prepared metal-rich wastewaters in this study. For the purpose, highly metal-resistant microalgal and bacterial species were isolated from a leading wastewater channel flowing through Lahore, Pakistan, and characterized at the molecular level. The microbial identities were proved after BLAST analysis. The microalgal (Chlorella vulgaris-BH1) and bacterial (Exiguobacterium profundum-BH2) species were then co-cultured in five different proportions. Five different proportions of potentially mutualistic microbial co-cultures (comprising of microalgal to bacterial cells in ratios of 1:3, 2:3, 3:3, 3:1, and 3:2) prepared thus were employed to remediate artificially prepared metal-loaded wastewaters. Three randomly selected toxic metals (Cu, Cr, and Ni) were used in this study to prepare metal-rich wastewaters. The microalgal-bacterial co-cultures were then exposed independently to the wastewaters containing 100 ppm of each of the above mentioned metals. The inoculated wastewaters were incubated maximally for a period of 15 days. The metal uptake was noted periodically after every 5 days. The results of the present study depicted that maximally about 78.7, 56.4, and 80% of Cu, Cr, and Ni were removed, respectively after an incubation period of 15 days. The microbial co-culture consisting of microalgal to bacterial cells in a ratio of 3:1 showed the highest remedial potential. The findings of the present study will be helpful in developing effective microalgal-bacterial consortia for economical, efficient, and environment-friendly rehabilitation of the polluted sites.


Assuntos
Bacillales/metabolismo , Chlorella vulgaris/metabolismo , Técnicas de Cocultura , Metais/metabolismo , Águas Residuárias/microbiologia , Poluentes Químicos da Água/metabolismo , Bacillales/efeitos dos fármacos , Bacillales/crescimento & desenvolvimento , Chlorella vulgaris/efeitos dos fármacos , Chlorella vulgaris/crescimento & desenvolvimento , Resistência a Medicamentos , Metais/toxicidade , Paquistão , Poluentes Químicos da Água/toxicidade
18.
Planta ; 249(4): 1189-1205, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30603788

RESUMO

MAIN CONCLUSION: Photoacclimation to variable light and photoperiod regimes in C. vulgaris represents a complex interplay between "biogenic" phytochrome-mediated sensing and "operational" redox sensing signaling pathways. Chlorella vulgaris Beijerinck UTEX 265 exhibits a yellow-green phenotype when grown under high light (HL) in contrast to a dark green phenotype when grown at low light (LL). The redox state of the photosynthetic electron transport chain (PETC) as estimated by excitation pressure has been proposed to govern this phenotypic response. We hypothesized that if the redox state of the PETC was the sole regulator of the HL phenotype, C. vulgaris should photoacclimate in response to the steady-state excitation pressure during the light period regardless of the length of the photoperiod. As expected, LL-grown cells exhibited a dark green phenotype, low excitation pressure (1 - qP = 0.22 ± 0.02), high chlorophyll (Chl) content (375 ± 77 fg Chl/cell), low Chl a/b ratio (2.97 ± 0.18) as well as high photosynthetic efficiency and photosynthetic capacity regardless of the photoperiod. In contrast, C. vulgaris grown under continuous HL developed a yellow-green phenotype characterized by high excitation pressure (1 - qP = 0.68 ± 0.01), a relatively low Chl content (180 ± 53 fg Chl/cell), high Chl a/b ratio (6.36 ± 0.54) with concomitantly reduced light-harvesting polypeptide abundance, as well as low photosynthetic capacity and efficiency measured on a per cell basis. Although cells grown under HL and an 18 h photoperiod developed a typical yellow-green phenotype, cells grown at HL but a 12 h photoperiod exhibited a dark green phenotype comparable to LL-grown cells despite exhibiting growth under high excitation pressure (1 - qP = 0.80 ± 0.04). The apparent uncoupling of excitation pressure and phenotype in HL-grown cells and a 12 h photoperiod indicates that chloroplast redox status cannot be the sole regulator of photoacclimation in C. vulgaris. We conclude that photoacclimation in C. vulgaris to HL is dependent upon growth history and reflects a complex interaction of endogenous systems that sense changes in photoperiod as well as photosynthetic redox balance.


Assuntos
Chlorella vulgaris/metabolismo , Cloroplastos/metabolismo , Chlorella vulgaris/crescimento & desenvolvimento , Chlorella vulgaris/fisiologia , Chlorella vulgaris/efeitos da radiação , Clorofila A/metabolismo , Cloroplastos/fisiologia , Transporte de Elétrons , Eletroforese em Gel de Poliacrilamida , Immunoblotting , Luz , Oxirredução , Fenótipo , Fotoperíodo , Fotossíntese/efeitos da radiação
19.
Bioprocess Biosyst Eng ; 42(3): 391-400, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30460400

RESUMO

Harvesting technology has a significant influence on the microalgal biomass industry. This study develops a buoy-bead flotation method and analyzes the factors impacting flotation. Experimental results show that adding sodium borosilicate as an alternative microsphere material can result in 58.5% harvesting efficiency, a 25.65% increase over the foam flotation average. The Plackett-Burman design experimental results reveal that pH conditions, microsphere diameter, and the speed of agitation are the three most important factors affecting harvesting efficiency. The interaction between these three factors was all found to be significant, which indicates that the harvesting efficiency was affected by a combination of multiple factors. Analyses of the Extended Derjaguin-Landau-Vewey-Overbeek (XDLVO) theory show that the Van der Waals interactions are the key factor in the attachment of algae and microspheres. A harvesting efficiency of 89.9% can be achieved at pH 10, with 56 µm dimeter microspheres and an agitation speed of 114 rpm.


Assuntos
Biomassa , Chlorella vulgaris/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Microesferas , Floculação
20.
Ultrason Sonochem ; 51: 496-503, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29793838

RESUMO

Lipids extracted from algal biomass could provide an abundant, rapidly growing, high yield feedstock for bio-diesel and other green fuels to supplement current fossil-based sources. Ultrasound pretreatment is a mechanical cell disruption method that has been shown to enhance lipid recovery from algae due to cavitation effects that disrupt algae cell walls. In this study, a locally grown mixture of Chlorella vulgaris/Cyanobacteria leptolyngbya was sonicated in an ultrasonic reactor with a clamp-on transducer prior to solvent lipid extraction. This configuration allows for a non-contact delivery method of ultrasonic energy with improved operational advantages (no fouling of transducer, continuous operation, and fully scalable design). A central composite design (CCD) was implemented to statistically analyze and evaluate the effect of ultrasonic power (350-750 W) and treatment time (5-30 min) on lipid yield. Lipid recovery was found to increase with both ultrasonic power and treatment time. Total lipid yields (on dry biomass basis) extracted via the Bligh and Dyer method from Chlorella vulgaris/cyanobacteria co-culture ranged from 8.3% for untreated algae to 16.9% for algae sonicated with 750 W power for 30 min, which corresponds to more than a doubling of lipid recovery due to ultrasound pretreatment. Increased power and treatment times were found to increase the degree of cell disruption as observed in the SEM and TEM images after ultrasonic pretreatment. Additionally, hexane (1:1 v/v) was evaluated as an alternative to the standard Bligh & Dyer (2:2:1.8 v/v/v chloroform/methanol/cell suspension) lipid extraction solvent system. On average, the Bligh and Dyer method extracted on average over twice the amount of lipids compared to hexane extraction. The lipid profile of the algae extracts indicates high concentrations of lauric acid (12:0), palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), and linoleic acid (18:2). This particular configuration of an ultrasonic system proved to be a viable method for the pretreatment of algae for enhanced lipid yields. Future research should focus on identifying alternative extraction solvents and expanding the range of treatment conditions to optimize the ultrasonic power and treatment times for maximum lipid recovery.


Assuntos
Fracionamento Químico/instrumentação , Técnicas de Cocultura , Cianobactérias/química , Lipídeos/isolamento & purificação , Microalgas/química , Transdutores , Ondas Ultrassônicas , Chlorella vulgaris/química , Chlorella vulgaris/crescimento & desenvolvimento , Cianobactérias/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Temperatura Ambiente
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