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1.
Sensors (Basel) ; 21(19)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34640866

RESUMO

Dissolved-oxygen concentration and temperature are amongst the crucial parameters required for the precise monitoring of biological and biomedical systems. A novel hybrid nanocomposite probe for real-time and contactless measurement of both dissolved-oxygen concentration and temperature, based on a combination of downconverting phosphorescent molecules of platinum octaethylporphyrin and lanthanide-doped upconverting nanoparticles immobilized in a host of polystyrene, is here introduced. Chlorella algae are employed here as a model to demonstrate the hybrid nanophotonic sensor's capability to monitor the aforementioned two parameters during the photosynthesis process, since these are among the parameters impacting their production efficiency. These algae have attracted tremendous interest due to their potential to be used for diverse applications such as biofuel production; however, feasibility studies on their economic production are still underway.


Assuntos
Chlorella , Nanopartículas , Oxigênio , Fotossíntese , Temperatura
2.
Chemosphere ; 283: 131204, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34467947

RESUMO

To overcome the bottlenecks of waste resource utilization and energy shortage that restrict the commercial production of microalgae biodiesel, volatile fatty acids (VFAs) derived from activated sludge were used as the sole carbon source to culture oleaginous microalgae Chlorella pyrenoidosa FACHB-1216 and Scenedesmus quadricauda FACHB-1297 under the mixotrophic and heterotrophic cultivation. Four VFAs ratios (acetic acids (AA): propionic acids (PA): butyric acids (BA)) were tested to determine the effects and mechanisms of the VFAs on the two microalgae. The highest lipid content (29.54%) and lipid production (71.10 mg L-1) were achieved by S. quadricauda at the VFAs ratio of 6: 1: 3 under heterotrophic condition, with 46.27% and 67.52% removal efficiencies of total nitrogen and phosphorus, respectively. The assimilation efficiency of AA was the highest at 73.37%, followed by that of PA and BA. For C. pyrenoidosa, VFAs promoted the rapid reproduction within 2 days under the heterotrophic condition at different initial inoculation densities. At the optimal VFA ratio, algae achieved the highest biomass concentration (0.14 ± 0.02 g L-1), with a specific growth rate of 0.91 d-1 and biomass productivity of 125.17 mg L-1 d-1. The removal rates of total nitrogen and phosphorus were 47.03% and 74.40%, respectively, and the assimilation efficiency of AA was the best (61.06%). High AA assimilation efficiency under the heterotrophic condition was beneficial for the algal growth and lipid accumulation. These results simultaneously produced microalgae-based bioenergy and recycled VFAs in anaerobically digested effluent.


Assuntos
Chlorella , Microalgas , Biomassa , Ácidos Graxos , Ácidos Graxos Voláteis , Processos Heterotróficos , Lipídeos , Nitrogênio
3.
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
4.
J Environ Manage ; 299: 113668, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34492441

RESUMO

This study aimed to evaluate the simultaneous interferences of Cu and Zn found in swine wastewater (SW) in the development of microalgae considering real conditions of cultivation in high rate algal ponds (HRAPs). Ten HRAPs on a pilot scale were fed with SW with different mixtures of Cu (0.5-3.0 mg/L) and Zn (5.0-25.0 mg/L). The interferences of these metals in removing nutrients (N-NH4+ and soluble phosphorus (Ps)) from the SW were determined. In addition, this study evaluated the effects on biomass growth and biochemical composition. Chlorella sp. was dominant in all HRAPs and the condition that potentiated its growth occurred in medium containing 1.8 mg Cu/L + 15.0 mg Zn/L, while higher concentrations conferred inhibition. Only Cu compromised the removal rates of N-NH4+ while the effects of Zn were not significant. Contrary, Zn interfered with Ps removal rates, but the impact of Cu was not significant. The greatest Cu applications increased the protein levels by biomass (50.5-55.2 %). Carbohydrate accumulation was favored by conditions that inhibited the development of microalgae due to either limitation or excess of metals. Copper and Zn compromised the levels of lipids, and the control treatment had the highest content (24.5 %). The presence of Cu and Zn changed the dynamics of HRAPs regarding nutrient removal, productivity, and biochemical composition of the biomass.


Assuntos
Chlorella , Microalgas , Purificação da Água , Animais , Biomassa , Nitrogênio/análise , Nutrientes , Lagoas , Suínos , Águas Residuárias , Zinco
5.
Aquat Toxicol ; 239: 105941, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34469852

RESUMO

The chlorophyte microalga Chlorella sorokiniana was tested for the bioremediation of heavy metals pollution. It was cultured with different concentrations of Cu2+, Cd2+, As (III) and As (V), showing a significant inhibition on its growth at concentrations of 500 µM Cu2+, 250 µM Cd2+, 750 µM AsO33- and 5 mM AsO43- or higher. Moreover, the consumption of ammonium was also studied, showing significant differences for concentrations higher than 1 mM of Cu2+ and As (III), and 5 mM of As (V). The determination of intracellular heavy metals concentration revealed that Chlorella sorokiniana is an outstanding Cd accumulator organism, able to accumulate 11,232 mg kg-1 of Cd, and removing 65% of initial concentration of this heavy metal. Finally, antioxidant enzymes, such as catalase (CAT) and ascorbate peroxidase (APX), and enzymes involved in the production of glutamate and cysteine, such as glutamine syntethase (GS), glutamate dehydrogenase (GDH), O-acetylserine (thiol) lyase (OASTL) and NAD-isocitrate dehydrogenase (NAD-IDH) were studied both at gene expression and enzymatic activity levels. These enzymes exhibited different grades of upregulation, especially in response to Cd and As stress. However, GS expression was downregulated when Chlorella sorokiniana was cultured in the presence of these heavy metals.


Assuntos
Chlorella , Metais Pesados , Microalgas , Poluentes Químicos da Água , Biodegradação Ambiental , Cádmio/toxicidade , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade
6.
Curr Microbiol ; 78(11): 3891-3900, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34510224

RESUMO

Ammonium sulfate wastewater can cause eutrophication and black odor of water body. Although ammonia nitrogen can be used as nutrient of microalgae, high ammonia nitrogen levels could inhibit the growth of microalgae. Nitrobacteria can transform ammonia nitrogen into nitrate nitrogen. In this study, mono Chlorella pyrenoidosa culture (mono-C.py), synchronous mixed culture (mixed-a), and asynchronous mixed culture (mixed-b) systems were examined for their ability to treat ammonium sulfate wastewater. Nitrogen removal rate of mixed-b at the end of culture (52.96%) was higher than that of the mono-C.py (46.37%) and the mixed-a (39.11%). Higher total suspended solid concentration (2.40 g/L), crude protein yield (0.76 g/L), and heating value yield (35.73 kJ/L) were obtained in mixed-b, meanwhile with excellent settlement performance (91.43 ± 0.51%). Mechanism analysis of settlement showed that the relative abundance of floc-forming-related bacteria Sphingopyxis and Acidovorax were increased generally, while nitrification/denitrifying members were decreased in mixed-b along with the culture proceeding.


Assuntos
Chlorella , Microalgas , Sulfato de Amônio , Biomassa , Águas Residuárias
7.
Curr Microbiol ; 78(11): 3901-3912, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34522979

RESUMO

The emerging aquaculture industry is in need of non-antibiotic-based disease control approaches to minimize the risk of antibiotic-resistant bacteria. Bacterial infections mainly caused by Vibrio spp. have caused mass mortalities of fish especially during the larval stages. The objectives of this study were to verify the potential of symbiotic probiont strains, isolated from microalgae (Amphora, Chlorella, and Spirulina) for suppressing the growth of Vibrio spp. and at the same time ascertain their abilities to enhance microalgal biomass by mutualistic interactions through microalgae-bacteria symbiosis. In addition, in vivo studies on Artemia bioencapsulated with probiont strains (single strain and mix strains) and microalgae were evaluated. The selected potential probionts were identified as Lysinibacillus fusiformis strain A-1 (LFA-1), Bacillus sp. strain A-2 (BA-2), Lysinibacillus fusiformis strain Cl-3 (LFCl-3), and Bacillus pocheonensis strain S-2 (BPS-2) using 16s rRNA. The cell densities of Amphora culture supplemented with BA-2 and Chlorella culture supplemented with LFCl-3 were higher than those of the controls. Artemia bioencapsulated with mix strains (LFA-1 + BA-2 + LFCl-3 + BPS-2) and Amphora demonstrated the highest survival rate compared to the controls, after being challenged with V. harveyi (60 ± 4%) and V. parahaemolyticus (78 ± 2%). Our study postulated that BA-2 and LFCl-3 were found to be good promoting bacteria for microalgal growth and microalgae serve as a vector to transport probiotic into Artemia. Moreover, mixture of potential probionts is beneficial for Artemia supplementation in conferring protection to Artemia nauplii against pathogenic Vibrios.


Assuntos
Chlorella , Vibrio , Animais , Artemia , Bacillaceae , Bacillus , RNA Ribossômico 16S , Simbiose , Vibrio/genética
8.
Ecotoxicol Environ Saf ; 225: 112750, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34530264

RESUMO

This study investigated the adsorption characterizations and mechanisms of lead (Pb) on biochar-derived microalgae residue (MB) produced at different pyrolytic temperatures. Six different MB samples were prepared from Chlorella sp. (CB) and Spirulina sp. (SB) in the temperature range of 200-600 â„ƒ, and microalgae residue power (MP) was used as a control. The effect of pH, adsorption kinetics and isotherms were studied for the different MBs, and a chemical analysis of Pb2+-loaded MP and MB was performed by SEM-EDS, XRD, XPS, FTIR, and Boehm titration. The results showed that Pb2+ adsorption on MP and MB was a monolayer chemical adsorption process. Precipitation with minerals, metal ion exchange, oxygen/nitrogen-containing functional groups (OFGs/NFGs), and coordination of Pb2+ with π electrons jointly contributed to Pb2+ adsorption on MP and MB. More specifically, the contribution of each mechanism depended on the pyrolytic temperature. The contribution of surface complexation and ion exchange decreased with increasing pyrolytic temperature due to the loss of OFGs/NFGs and decreasing metal ion content, while the contribution of precipitation and Pb2+-π interaction significantly increased. Overall, precipitation with minerals and ion exchange dominated Pb2+ adsorption on MP and MB, which accounted for 65.20-74.40% of the total adsorption capacity. Surface precipitation contributed to a maximum adsorption capacity for high-temperature CB and SB (600 â„ƒ) of up to 131.41 mg/g and 154.56 mg/g, respectively. In conclusion, MB adsorbents are a promising material for the remediation of heavy metal-bearing aquatic environments.


Assuntos
Chlorella , Microalgas , Adsorção , Carvão Vegetal , Chumbo , Temperatura
9.
Mar Environ Res ; 171: 105469, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34500299

RESUMO

Products designed to filter ultraviolet (UV) light are responsible for growing levels of anthropogenic environmental contamination. Octinoxate (ONT) is among the most common UV filtering active ingredients in cosmetics and sunscreens. The present study was designed to evaluate the toxicological effects of ONT on the photosynthetic activity of the Chlorella species of marine microalgae. These analyses identified ONT as a potent photo-toxicant, the effects of which were more pronounced upon light exposure relative to in the dark. Short-term ONT exposure had no effect on photosynthetic electron transport capacity in the dark but did significantly reduce the ribulose-1,5-bisphosphate carboxylase/oxygenase activity in Chlorella cells, suggesting that this compound can directly suppress the photosynthetic Calvin cycle. When cells were subsequently exposed to light, the disruption of this cycle resulted in an excess of excitation energy, in turn driving the excessive generation of reactive oxygen species (ROS). ROS-mediated disruption of cellular metabolism further aggravated this ONT-induced microalgal damage. As such, under natural light conditions, these microalgae cells are exposed to increased oxidative stress that impairs their growth and causes pigment bleaching. Restricting the utilization of ONT-containing sunscreens thus has the potential to better preserve the integrity of aquatic and terrestrial ecosystems.


Assuntos
Chlorella , Microalgas , Cinamatos , Ecossistema , Fotossíntese , Protetores Solares/toxicidade
10.
J Environ Manage ; 297: 113210, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34375226

RESUMO

The aim of this work is remediation of dairy wastewater (DWW) for biodiesel feedstock production using poly-microalgae cultures of four microalgae namely Chlorella minutissima (C. minutissima), Scenedesmus abundans (S. abundans), Nostoc muscorum (N. muscorum) and Spirulina sp. The poly-microalgae cultures were prepared as C. minutissima + N. muscorum (CN), C. minutissima + N. muscorum + Spirulina sp. (CNSS) and S. abundans + N. muscorum + Spirulina sp. (SNSS). Poly-microalgae culture CNSS cultivated on 70% DWW achieved 75.16, 61.37, 58.76, 84.48 and 84.58%, removals of biological oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and suspended solids (SS), respectively, at 12:12 h photoperiod that resulted into total biomass and lipid yield of 3.47 ± 0.07 g/L and 496.32± 0.065 mg/L. However, maximum biomass and lipid yields of 5.76 ± 0.06 and 1152.37 ± 0.065 mg/L were achieved by poly-microalgae culture CNSS cultivated on 70% DWW + 10 g/L of glucose at 18:6 h photoperiod. Fatty acid methyl ester (FAME) analysis shown presence of C14:0 (myristic acid) C16:0 (palmitic acid), C16:1 (palmitoleic acid), C18:0 (stearic acid), C18:2 (linoleic acid) and C18:3 (linolenic acid), it indicates that the lipids produced from poly-microalgae cultures are suitable for biodiesel production. Thus, poly-microalgae cultures could be more efficient than mono-microalgae cultures in the remediation of DWW and for biodiesel feedstock production.


Assuntos
Chlorella , Microalgas , Biocombustíveis/análise , Biomassa , Nitrogênio , Águas Residuárias
11.
Bioresour Technol ; 340: 125670, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34364083

RESUMO

The present research describes yeast assisted algal flocculation followed by evaluation of algae-yeast flocs for nutritional profile as potent food product. Co-flocculation of Chlorella pyrenoidosa using Saccharomyces cerevisiae showed 58.33 ± 2.37% flocculation efficiency. Nutrient composition of algae-yeast flocs (CP-Y) depicted higher protein content (35.52%) as compared to algae (23.72%) and yeast biomass (33.89). Amino acid profiles of CP-Y biomass depicted increase in essential amino acid content with higher ratio of essential to non-essential amino acid (0.68) as compared to Y (0.57) and CP (0.57) biomass. Lipid and carbohydrate content of CP-Y flocs was estimated as 26.95 ± 0.57% and 21.12 ± 0.83%, respectively. Fatty Acid Methyl Esters (FAME) analysis showed presence of omega rich polyunsaturated fatty acids (PUFAs) like α-linolenic acid (ω-3), Linoleic acid (ω-6), Palmitoleic acid (ω-7) etc in CP-Y biomass. The study provides novel insights on nutrition enriched biomass obtained after algal-yeast flocculation, which can be a better alternative to existing flocculation methods for food applications.


Assuntos
Chlorella , Microalgas , Biomassa , Suplementos Nutricionais , Floculação , Saccharomyces cerevisiae
12.
Environ Sci Technol ; 55(17): 11916-11924, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34424674

RESUMO

The mechanism of self-flocculation remains unclear, partially impeding its efficiency enhancement and commercial application of microalgae-based municipal wastewater (MW) bioremediation technology. This study revealed the contributions of exoproteins [PN, proteins in extracellular polymeric substances (EPS)] to the separation of indigenous microalgae from treated MW. Compared to the low light intensity group, the high light intensity (HL) group produced Chlorella sp. with 4.3-fold higher self-flocculation efficiencies (SE). This was attributed to the enriched biological functions and positional rearrangement of increased PN within 2.9-fold higher EPS. Specifically, a total of 75 PN was over-expressed in the HL group among the 129 PN identified through label-free proteomics. The algal cell-adhesion molecules (Algal-CAMs) and metal-ion-binding PN were demonstrated as two dominant contributors promoting cell adhesion and bridging, through function prediction based on the contained domains. The modeled 3D structure showed that Algal-CAMs presented less hydrophilic α-helix abundance and were distributed in the outermost position of the EPS matrix, further facilitating microalgal separation. Moreover, the 10.1% lower hydrophily degree value, negative interfacial free energy (-19.5 mJ/m2), and 6.8-fold lower energy barrier between cells also supported the observed higher SE. This finding is expected to further fill the knowledge gap of the role of PN in microalgal self-flocculation and promote the development of biomass recovery from the microalgae-wastewater system.


Assuntos
Chlorella , Microalgas , Biomassa , Floculação , Águas Residuárias
13.
Sci Total Environ ; 791: 148362, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34412414

RESUMO

This study evaluated the effect of high rate ponds (HRPs) depth on algal biomass production during domestic wastewater treatment. HRPs were evaluated for 20, 30, and 40 cm depths, with and without CO2 supplementation. In addition, 40 cm deep HRP with ultraviolet (UV) pre-disinfection was evaluated. The concentration of chlorophyll-a as a function of time for each evaluated condition was represented by logistic models that were after submitted to cluster analysis. The 20 cm HRPs presented higher chlorophyll-a concentration, reaching a maximum of 5.8 and 4.3 mg L-1, in the HRPs with and without CO2 addition, respectively. Ammonia nitrogen and soluble phosphorus were greater removed in shallower HRPs. The addition of CO2 influenced the nutrient removal processes, optimizing nutrient recovery by biomass assimilation. HRP configuration did not influence organic matter removal (~40% of removal efficiency in all HRPs), predominant microalgae genera (Chlorella sp. and Scenedesmus), and E. coli inactivation (removal of ~2 log units), except for the 20 cm HRP without CO2 that had removal of 4 log units due to high pH values. For HRPs with CO2 addition and UV pre-disinfection, the models for 40 cm were grouped together with those obtained for 30 cm HRPs, indicating the same behavior for chlorophyll-a production as a function of time. Thus, it can be concluded that the evaluated strategies represent alternatives for reducing HRP area requirements. Moreover, results may represent advancement and major contributions for HRP design criteria.


Assuntos
Chlorella , Purificação da Água , Biomassa , Escherichia coli , Lagoas , Eliminação de Resíduos Líquidos
14.
J Biotechnol ; 340: 64-74, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34454961

RESUMO

Biodiesel, as a renewable and eco-friendly energy source that can be produced through algae oil esterification, has recently received much attention. Maximization of algal biomass and lipid content is crucial for commercial biodiesel production. In this study, Chlorella sp. PG96, a microalgal strain isolated from urban wastewater, was identified considering its morphological and molecular characteristics. Fractional factorial design (211-7) was employed to screen medium and environmental factors for achieving high lipid productivity. The effects of eleven factors including light intensity, light spectrum, aeration rate, temperature, salinity, NaHCO3, CO2, NaNO3, NH4Cl, MgSO4.7H2O, and K2HPO4 and their interactions on growth characteristics of Chlorella sp. PG96 (biomass and lipid production) were statistically assessed. Based on the experimental results, lipid productivity was at its maximum (54.19 ± 8.40 mglipid L-1 day-1) under a combination of high levels of all factors. The analysis also showed that physical parameters of light intensity and temperature were more effective on algal growth compared to nutritional parameters. Furthermore, nitrogen source of ammonium and carbon source of bicarbonate played more significant roles in biomass and lipid production, compared with nitrate and CO2, respectively. Although the effect of sulfur limitation on cellular growth was similar to phosphorus deficiency, S-limitation had a greater impact on lipid accumulation. The interaction between NaHCO3 and NH4Cl was the most prominent interaction affecting all responses. It is concluded that Chlorella sp. PG96 at a high level of light intensity and temperature (22500 Lux and 32 °C, respectively) can be a prospective candidate for biodiesel production.


Assuntos
Chlorella , Microalgas , Biocombustíveis , Biomassa , Lipídeos , Estudos Prospectivos
15.
Bioresour Technol ; 341: 125646, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34418844

RESUMO

The aim of this work was to study the flocculation efficiency of algal biomass (Chlorella pyrenoidosa) in coupling with waste materials i.e. poultry excreta leachate by using other waste material which was obtained from deposition of scaling in electric geyser. Utilization of electric geyser waste material deposit (EGWMD) for flocculation is a novel approach because of various elements which are replica of chemical flocculants responsible for flocculation mechanism in culture medium. Flocculation process was optimized by response surface methodology and 98.21% flocculation efficiency was achieved with designed process parameters as temperature 32.5 °C, flocculant dose 275 mgL-1, pH 5 and time 30 min. The reusability of spent medium was also analyzed at 70.2% and 32.5% flocculation efficiency with two successive steps. The cellular morphology of pre-harvested and post-harvested Chlorella pyrenoidosa was also observed. EGWMD is abundant and freely available that has no application till now and can alternate of chemical flocculants.


Assuntos
Chlorella , Microalgas , Animais , Biomassa , Floculação , Aves Domésticas
16.
Nat Plants ; 7(9): 1314-1322, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34462576

RESUMO

Photosynthesis in deserts is challenging since it requires fast adaptation to rapid night-to-day changes, that is, from dawn's low light (LL) to extreme high light (HL) intensities during the daytime. To understand these adaptation mechanisms, we purified photosystem I (PSI) from Chlorella ohadii, a green alga that was isolated from a desert soil crust, and identified the essential functional and structural changes that enable the photosystem to perform photosynthesis under extreme high light conditions. The cryo-electron microscopy structures of PSI from cells grown under low light (PSILL) and high light (PSIHL), obtained at 2.70 and 2.71 Å, respectively, show that part of light-harvesting antenna complex I (LHCI) and the core complex subunit (PsaO) are eliminated from PSIHL to minimize the photodamage. An additional change is in the pigment composition and their number in LHCIHL; about 50% of chlorophyll b is replaced by chlorophyll a. This leads to higher electron transfer rates in PSIHL and might enable C. ohadii PSI to act as a natural photosynthesiser in photobiocatalytic systems. PSIHL or PSILL were attached to an electrode and their induced photocurrent was determined. To obtain photocurrents comparable with PSIHL, 25 times the amount of PSILL was required, demonstrating the high efficiency of PSIHL. Hence, we suggest that C. ohadii PSIHL is an ideal candidate for the design of desert artificial photobiocatalytic systems.


Assuntos
Adaptação Ocular/fisiologia , Proliferação de Células/fisiologia , Chlorella/metabolismo , Chlorella/ultraestrutura , Ritmo Circadiano/fisiologia , Temperatura Alta , Complexo de Proteína do Fotossistema I/metabolismo
17.
Bioresour Technol ; 340: 125593, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34311176

RESUMO

The present study is aimed to understand the photosynthetic transients of Chlorella sorokiniana SVMBIOEN2 during treatment of dairy wastewater under different light intensities (100, 150, and 200 µmol m-2s-1) in mixotrophic mode. Light intensities showed marked influence on photosystem behavior, lipid profile, and organic pollutant removal. Analysis of Chlorophyll a fluorescence transient including Fv/Fm, ETo/RC, TRo/RC, and Abs/RC showed better photosystem efficiency at 100 µmol m-2s-1 operations. OJIP curve fitting depicted a positive L-band at 150 µmol m-2s-1 indicating lower kinetic energy of photosystem II (PSII) reaction centres at high light intensities. Better photosynthetic activity at 100 µmol m-2s-1 operations resulted in good assimilation of biomass (2.3 g L-1), carbohydrates (10.2 mg g-1), and proteins (14 mg g-1) with a significant reduction in chemical oxygen demand (85%). Phycoremediation of dairy wastewater accumulates predominantly monounsaturated fatty acids followed by polyunsaturated fatty acids showing the application of C. sorokiniana in nutraceutical and food industries.


Assuntos
Chlorella , Águas Residuárias , Chlorella/metabolismo , Clorofila , Clorofila A , Luz , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo
18.
Bioresour Technol ; 339: 125502, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34304097

RESUMO

Septic tank effluent from rural areas was an ideal medium for cultivating oleaginous microalgae. However, the characteristics of septic tank effluents varied greatly due to the different incoming wastewater, and bring uncertain risks for algal growth. In this study, an oleaginous microalgae was cultivated in septic effluents from different mixed wastewater. The results showed that the effluent from pure toilet wastewater was the best medium to achieve the highest biomass yield (1.68 g·L-1) and productivity (154.6 mg·L-1·d-1). In contrast, the discharge of kitchen or laundry wastewater reduced the biomass production by 50.5-79.1%. That caused much lower lipids production in effluents from mixed wastewater regardless of its high lipids content and saturation degree. The results suggest that the discharge of kitchen or laundry wastewater bring risks for biomass and lipids production, and should be separated from the toilet wastewater before entering into septic tank.


Assuntos
Chlorella , Poluentes Ambientais , Microalgas , Lipídeos , Águas Residuárias
19.
Sci Total Environ ; 795: 148772, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34247079

RESUMO

Due to the negative impact of climate change and anthropogenic activities, bromide intrusion into algae-impacted freshwater becomes a new challenge for safe drinking water supply worldwide, as bromide and algal organic matter are important disinfection byproduct (DBP) precursors. However, the influences of this phenomenon on algal precursor dynamic and their derived DBPs have to date received little attention. This study examined the effects of bromide intrusion on algal intra- (IOM) and extra-cellular (EOM) precursors during the growth of two freshwater algae Chlorella sp. and Microcystis aeruginosa. Both algae were well-adapted to Br-intrusion, and no significant effect on their growth and their IOM and EOM precursor characteristics was statistically found (p > 0.05). Notwithstanding, this phenomenon apparently added bromide ions into the algal-EOM solution, which resulted in a linear uptake of bromide by IOM. Under Br-intrusion from 0-4 mg/L (Br0-Br4), 15-60% (on average) of the initial bromide additions remained in the algal EOM. By contrast, only an average of ~1.5-2.4% of the additional bromide was taken up by the IOM, resulting in an elevation of brominated DBPs (Br-DBPs) upon chlorination, especially for those samples collected in the late exponential and declined growth phases. When Br0 shifted to Br4, the %Br-DBP yields from both IOM and EOM increased by more than 75%, with a corresponding increasing the total DBP yield of ~30%. The toxic potencies of all chlorinated Br-containing IOM/EOM were thus magnified, by over one order magnitude greater than the non-Br IOM/EOM at Br0. These results are highly significant for understanding the potential risks of Br-intrusion and algal blooming in raw water quality prior to chlorination.


Assuntos
Chlorella , Desinfetantes , Microcystis , Poluentes Químicos da Água , Purificação da Água , Brometos , Desinfetantes/toxicidade , Desinfecção , Halogenação , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
20.
Sci Total Environ ; 793: 148598, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34328983

RESUMO

This study investigated the effect of CaO2 pretreatment on sulfonamide antibiotics (SMs) remediation by Chlorella sp. Results showed that a CaO2 dose ranging from 0.05 to 0.1 g/g biomass was the best and led to higher SMs removal efficacy 5-10% higher than the control. The contributions made by cometabolism and CaO2 in SMs remediation were very similar. Bioassimilation could remove 24% of sulfadiazine (SDZ) and sulfamethazine (SMZ), and accounted for 38% of sulfamethoxazole (SMX) remediation. Pretreatment by CaO2 wielded a positive effect on microalgae. The extracellular polymeric substances (EPS) level of the CaO2 pretreatment microalgae was three times higher when subjected to non-pretreatment. For the long-term, pretreatment microalgae removed SMs 10-20% more than the non-pretreatment microalgae. Protein fractions of EPS in continuous operation produced up to 90 mg/L for cometabolism. For bioassimilation, SMX intensity of the pretreatment samples was 160-fold less than the non-treatment one. It indicated the CaO2 pretreatment has enhanced the biochemical function of the intracellular environment of microalgae. Peroxidase enzyme involved positively in the cometabolism and degradation of SMs to several metabolites including ring cleavage, hydroxylation and pterin-related conjugation.


Assuntos
Chlorella , Microalgas , Antibacterianos , Peróxidos , Sulfonamidas
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