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Photocatalytic hydrogen production is a prevalent method for hydrogen synthesis. However, high recombination rate of photogenerated carriers and high activation energy barrier of H remain persistent challenge. Here, the two-step hydrothermal method is utilized to prepare dual S-defect mediated catalyst molybdenum sulfide/zinc indium sulfide (MSv/ZISv), which has high hydrogen production rate of 8.83 mmol g-1h-1 under simulated sunlight. The achieved rate is 21.91 times higher than pure ZnIn2S4 substrate. Defects in ZIS within MSv/ZISv modify the primitive electronic structure by creating defect state that retaining good reducing power, leading to the rapid separation of electron-hole pairs and the generation of additional photogenerated carriers. The internal electric field further enhances the migration toward to cocatalyst. Simultaneously, the defects introduced on the MoS2 cause electron rearrangement, leading to electron clustering on both S vacancies and edge S. Thereby MSv/ZISv exhibits the lowest activation energy barrier and |ΔGH*|. This work explores the division of synergies between different types of S defects, providing new insights into the coupling of defect engineering.
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Roxarsone (ROX) is the main form of arsenic pollution in the world, and developing effective methods for its elimination is beneficial to human health and the ecological environment. Herein, we report glutaraldehyde cross-linked chitosan-encapsulated CoCe-LDH (layered double hydroxides) as an outstanding catalyst for the advanced oxidation of ROX and the efficient adsorption of inorganic arsenic. 100% of ROX and more than 98.5% of As(III)/As(V) were eliminated, and over 99.3% of remaining inorganic arsenic was oxidized to low-toxicity As(V) in the peroxymonosulfate (PMS) activation system, and some specific properties of LDH are considered the main reasons. The hierarchical anion exchange has been confirmed to be beneficial for constructing a high-concentration PMS interlayer microenvironment. The unique reverse electron transfer process induced 100% selective production of singlet oxygen. This work not only develops an advanced ROX removal method but also provides a new understanding of the LDH-based advanced oxidation process.
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Additives could improve composting performance and reduce gaseous emission, but few studies have explored the synergistic of additives on H2S emission and compost maturity. This research aims to make an investigation about the effects of chemical additives and mature compost on H2S emission and compost maturity of kitchen waste composting. The results showed that additives increased the germination index value and H2S emission reduction over 15 days and the treatment with both chemical additives and mature compost achieved highest germination index value and H2S emission reduction (85%). Except for the treatment with only chemical additives, the total sulfur content increased during the kitchen waste composting. The proportion of effective sulfur was higher with the addition of chemical additives, compared with other groups. The relative abundance of H2S-formation bacterial (Desulfovibrio) was reduced and the relative abundance of bacterial (Pseudomonas and Paracoccus), which could convert sulfur-containing substances and H2S to sulfate was improved with additives. In the composting process with both chemical additives and mature compost, the relative abundance of Desulfovibrio was lowest, while the relative abundance of Pseudomonas and Paracoccus was highest. Taken together, the chemical additives and mature compost achieved H2S emission reduction by regulating the dynamics of microbial community.
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Compostaje , Microbiota , Suelo/química , Gases , AzufreRESUMEN
Traditional defect engineering and doping strategies are considered effective means for improving H2 evolution, but the uncontrollability of the modification process does not always lead to efficient activity. A defect-induced heteroatom refilling strategy is used here to synthesize heteroatoms introduced carbon nitride by precisely controlling the "introduction" sites on efficient N1 sites. Density functional theory calculations show that the refilling of B, P, and S sites have stronger H2 O adsorption and dissociation capacity than traditional doping, which makes it an optimal H2 production path. The large internal electric field strength of heteroatom-refilled catalysts leads to fast electron transfer and the hydrogen production of the best sample is up to 20.9 mmol g-1 h-1 . This work provides a reliable and clear insight into controlled defect engineering of photocatalysts and a universal modification strategy for typical heteroatom and co-catalyst systems for H2 production.
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Due to low consumption and high efficiency, in situ microbial remediation of petroleum hydrocarbons (PHs)-contaminated sites in in-service petrochemical enterprises has attracted more and more attention. In this study, a degrading strain was isolated from oil depot-contaminated soil with soil extract (PHs) as the sole carbon source, identified and named Rhodococcus sp. OBD-3. Strain OBD-3 exhibited wide adaptability and degradability over a wide range of temperatures (15-37 °C), pH (6.0-9.0), and salinities (1-7% NaCl) to degrade 60.6-86.6% of PHs. Under extreme conditions (15 °C and 3-7% salinity), PHs were degraded by 60.6 ± 8.2% and more than 82.1% respectively. In OBD-3, the alkane monooxygenase genes alkB1 and alkB2 (GenBank accession numbers: MZ688386 and MZ688387) were found, which belonged to Rhodococcus by sequence alignment. Moreover, strain OBD-3 was used in lab scale remediation in which the contaminated soil with OBD-3 was isolated as the remediation object. The PHs were removed at 2,809 ± 597 mg/kg within 2 months, and the relative abundances of Sphingobium and Pseudomonas in soil increased more than fivefold. This study not only established a system for the isolation and identification of indigenous degrading strains that could efficiently degrade pollutants in the isolated environment but also enabled the isolated degrading strains to have potential application prospects in the in situ bioremediation of PHs-contaminated soils.
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Petróleo , Rhodococcus , Petróleo/metabolismo , Biodegradación Ambiental , Rhodococcus/genética , Rhodococcus/metabolismo , Hidrocarburos/metabolismo , Suelo , Microbiología del SueloRESUMEN
This study investigated the effects of different carbon-based additives including biochar, woody peat, and glucose on humic acid, fulvic acid, and phosphorus fractions in chicken manure composting and its potential for phosphorus mobilization in soil. The results showed that the addition of glucose effectively increased the total humic substance content (90.2 mg/g) of composts, and the fulvic acid content was significantly higher than other groups (P < 0.05). The addition of biochar could effectively improve the content of available phosphorus by 59.9% in composting. The addition of carbon-based materials to the composting was beneficial for the production of more stable inorganic phosphorus in the phosphorus fraction. The highest proportion of soluble inorganic phosphorus components of sodium hydroxide was found in group with woody peat addition (8.7%) and the highest proportion of soluble inorganic phosphorus components of hydrochloric acid was found in group with glucose addition (35.2%). The compost products with the addition of biochar (humic acid decreased by 17.9%) and woody peat (fulvic acid decreased by 72.6%) significantly increased soil humic acid mineralization. The compost products with the addition of biochar was suitable as active phosphate fertilizer, while the compost products with the addition of glucose was suitable as slow-release phosphate fertilizer.
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Compostaje , Sustancias Húmicas/análisis , Suelo , Carbono/metabolismo , Fósforo , Fertilizantes , Estiércol , Fosfatos , GlucosaRESUMEN
Three parallel bioreactors were operated with different inoculation of activated sludge (R1), intertidal sludge (ItS) (R2), and ItS-added AS (R3), respectively, to explore the effects of ItS bioaugmentation on the formation of salt-tolerant aerobic granular sludge (SAGS) and the enhancement of COD removal performance. The results showed that compared to the control (R1-2), R3 promoted a more rapid development of SAGS with a cultivation time of 25 d. Following 110-day cultivation, R3 exhibited a higher granular diameter of 1.3 mm and a higher hydrophobic aromatic protein content than that in control. Compared to the control, the salt-tolerant performance in R3 was also enhanced with the COD removal efficiency of 96.4% due to the higher sludge specific activity of 14.4 g·gVSS-1·d-1 and the salinity inhibition constant of 49.3 gL-1. Read- and genome-resolved metagenomics together indicated that a higher level of tryptophan/tyrosine synthase gene (trpBD, tyrBC) and enrichment of the key gene hosts Rhodobacteraceae, Marinicella in R3, which was about 5.4-fold and 1.4-fold of that in control, could be the driving factors of rapid development of SAGS. Furthermore, the augmented salt-tolerant potential in R3 could result from that R1 was dominated by Rhodospirillaceae, Bacteroidales, which carried more trehalose synthase gene (otsB, treS), while the dominant members Rhodobacteraceae, Marinicella in R3 were main contributors to the glycine betaine synthase gene (ectC, betB, gbsA). This study could provide deeper insights into the rapid development and improved salt-tolerant potential of SAGS via bioaugmentation of intertidal sludge, which could promote the application of hypersaline wastewater treatment.
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Aguas del Alcantarillado , Purificación del Agua , Aguas del Alcantarillado/química , Eliminación de Residuos Líquidos/métodos , Reactores Biológicos , Salinidad , AerobiosisRESUMEN
In this study, the salt-tolerant aerobic granular sludge (SAGS) was cultivated with the increased salinity (0-9% NaCl), showing oval shape, and clear outline. The related sludge characteristics in the formation process of SAGS as well as the effects of salinity on the performance (removal ability, sludge biomass and EPS component) of SAGS were evaluated. Increased salinity accelerated the formation of SAGS, and resulted in the excess secretion of EPS. Relationship between EPS and settling capacity of SAGS was determined, with the increase of salinity, SVI decreased linearly and the sedimentation performance of granular sludge was enhanced. Pearson correlation analysis showed that shorter settling time (3 min) and longer anaerobic influent time (30 min) were beneficial to the operation of SAGS reactor. Metagenomics results showed that the SAGS was dominated by Candida, Halomonas and other salt-tolerant bacteria, the enrichment of these salt-tolerant microbes played an important role in maintaining the stability of granular sludge system and improving the overall salt-tolerant performance. Compared with S9 samples, the proteome regulation in S0 sample was more active and the abundance of Cell motility related proteins was 5 times higher than that in S9 samples. Extracellular structure related proteins was more active in S9, and its abundance was 3.6 times that of S0.
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Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Aerobiosis , Reactores Biológicos/microbiología , Metagenómica , Salinidad , Aguas del Alcantarillado/química , Eliminación de Residuos Líquidos/métodosRESUMEN
To further reduce the energy consumption in the wastewater biological nitrogen removal process, partial nitrification and its integrated processes have attracted increasing attentions owing to their economy and efficiency. Shortening the steps of ammonia oxidation to nitrate saves a large amount of aeration, and the accumulated nitrite could be reduced by denitritation or anammox, which requires less electron donors compared with denitrification. Therefore, the strategies through mainstream suppression and sidestream inhibition for the achievement of partial nitrification in recent years are reviewed. Specifically, the enrichment strategies of functional microorganisms are obtained on the basis of their growth and metabolic characteristics under different selective pressures. Furthermore, the promising developments, current application bottlenecks and possible future trends of some biological nitrogen removal processes integrating partial nitrification are discussed. The obtained knowledge would provide a new idea for the fast realization of economic, efficient and long-term stable partial nitrification and biological nitrogen removal process.
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Nitrificación , Nitrógeno , Biodegradación Ambiental , Reactores Biológicos , Desnitrificación , Oxidación-Reducción , Aguas ResidualesRESUMEN
A halophilic PAHs-degrading strain, Martelella AD-3, was previously isolated from highly saline petroleum-contaminated soil. In this study, label-free proteomics were performed to identify differentially expressed proteins (DEPs) under Group P (phenanthrene +5% salinity) and Group G (glycerol +1% salinity), which would help to reveal the mechanism of phenanthrene degradation and salt tolerance. A total of 307 up-regulated DEPs were found in Group P, including 17 phenanthrene degradation proteins. Among these phenanthrene-degrading proteins, the ferredoxin of aromatic ring-hydroxylating dioxygenase (RHD) was up-regulated by 110-fold and gentisate 1,2-dioxygenases (GDOs) were only expressed in Group P. Besides, we also found nine high salt stress response proteins, including ectoine synthase and transport protein of compatible (osmoprotectant) solutes, were differentially up-regulated. These results indicate that strain AD-3 mainly relied on RHD and dihydrodiol dehydrogenase to degrade phenanthrene, and accumulated compatible solutes for resistance to salt stress. This study provides strong theoretical guidance for understanding the degradation of phenanthrene by strain AD-3 in high salt environments.
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Alphaproteobacteria , Fenantrenos , Biodegradación Ambiental , Fenantrenos/toxicidad , Proteómica , Tolerancia a la SalRESUMEN
Tris(1,3-dichloro-2-propyl)phosphate (TDCPP) is an environmental contaminant that has attracted increasing concern due to its presence in environmental media and biological samples. Our previous study demonstrated that exposure to TDCPP reduced the lifespan of Caenorhabditis elegans, but the mechanisms, including the relevant signaling pathways, are unclear. The current study found that TDCPP exposure triggers an unconventional insulin/insulin-like growth factor signaling (IIS) pathway, not by disrupting the insulin-like growth factor-1 receptor DAF-2/IGF1R but by inhibiting the downstream tumor-suppressor factor DAF-18/PTEN. This inhibition reduces PI(3,4,5)P3 (PIP3) dephosphorylation, causing buildup that increases the activation of the Akt/Protein Kinase B (PKB) family of serine/threonine kinases. This activation induces DAF-16/FoxO phosphorylation and promotes the sequestration of DAF-16/FoxO in the cytoplasm, reducing the lifespan of nematodes. Our results have important diagnostic and therapeutic implications for controlling TDCPP-related diseases, especially those originating with IIS pathway components.
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Proteínas de Caenorhabditis elegans , Longevidad , Animales , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Factores de Transcripción Forkhead/metabolismo , Insulina , Factor I del Crecimiento Similar a la Insulina , Mutación , Compuestos Organofosforados , Fosfatos , Receptor de Insulina/metabolismo , Transducción de SeñalRESUMEN
Optimizing the heterojunction structure of semiconductor photocatalysts is vital for utilizing their abilities in organic matter degradation. Herein, a novel fabrication of a Z-scheme system with inverse opal g-C3N4 and BiOBr via a reflux process is developed. On the one hand, the unique inverse opal construction, formed by using silica (SiO2) photonic crystals as the template, not only provides a larger surface area for adsorption of antibiotics but also improves the separation and transfer efficiency of photogenerated electrons and holes as well as visible light absorption ability. On the other hand, by imitating natural photosynthesis, the artificial Z-scheme system with an inverse opal g-C3N4-BiOBr nanojunction further promotes the separation of photogenerated electrons and holes. The obtained IO CN/BiOBr catalyst exhibits superior photocatalytic performance for antibiotics degradation under visible light irradiation. In a typical test, almost complete degradation of levofloxacin (LVX) (10 mg L-1) could be achieved within 50 min due to the proper bandgap match between inverse opal g-C3N4 and BiOBr as well as enhanced surface area and light absorption. The present work provides an alternative strategy for construction of novel visible-light-driven Z-scheme photocatalysts and offers some new insights into the methods of waste water treatment.
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Antibacterianos/química , Bismuto/química , Levofloxacino/química , Contaminantes Químicos del Agua/química , Adsorción , Catálisis , Luz , Procesos Fotoquímicos , Dióxido de Silicio/química , Propiedades de SuperficieRESUMEN
Aerobic granular sludge (AGS) technology is generally negatively affected by the salinity in high saline organic wastewater. The effect of salinity on organic pollutants removal of AGS was studied in three parallel sequencing batch reactors. The results indicated that the performance of reactors operating at relative low salinity (1%) remained stable. However, at medium salinity (2%) and higher salinity (4%) conditions, the organic pollutants removal efficiencies deteriorated from 93.7 ± 3.0 to 71.6 ± 6.8 and 53.6 ± 5.4%, respectively. The addition of a mixture of acyl-homoserine lactone (AHL) mediated quorum sensing (QS) signaling molecules (0.1 µmol/L of mixed C6-HSL, C8-HSL and 3OC8-HSL) only restored the performance of the 2% salinity reactor back to 86.3 ± 6.2% due to the changing of hydrophobic extracellular polymeric substance ratio from 64 ± 3 to 71 ± 4%. Addition of the AHL had no effect on the pollution removal efficiency at the 4% salinity conditions. Microbial community analysis showed that Dyella (32.3%) species were the dominant member of the community and its occurrence was positively correlated with organic pollutants removal efficiency at relative high salinity (2% and 4%), while Mangrovibacter showed the opposite trend. Higher abundances of hdtS and acylase genes, the synthesis and degradation genes of AHL, were found after adding AHLs to reactors at 2% salinity, which indicated that AHL mediated QS was the primary QS system in salt-tolerant AGS.
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Microbiota , Aguas del Alcantarillado , Acil-Butirolactonas , Biodegradación Ambiental , Matriz Extracelular de Sustancias Poliméricas , Percepción de Quorum , Tolerancia a la SalRESUMEN
Eutectic freeze crystallization was developed to recover sodium erythorbate (NaE) from wastewater at pHs 4.1, 5.3, and 6.5. Two substances (A and B) were sequentially recovered from the samples. The recovery rate of substance A was 2.06, 1.83, and 3.03 g/L at pHs 4.1, 5.3, and 6.5, respectively; while that of B was 5.51, 3.09, and 3.26 g/L at the corresponding pHs. The analysis results of the two recovered substances indicated that substance A was mostly Na2 SO4 ·10H2 O, while substance B was mainly NaE. Salt recovery was most successful at pH 4.1 with the purity of recovered NaE reaching 87.53 wt%. Moreover, the chemical oxygen demand and electric conductivity of the ice were far smaller than the initial wastewater. The concentration effect was minimal due to the formation of Na2 SO4 ·10H2 O and NaE crystals. This combined crystallization strategy can potentially become an economic technology to recover NaE from wastewater. Practitioner points Segregation of NaE and Na2 SO4 ·10H2 O during the freeze crystallization process. Recovering 5.53 kg NaE with the purity of 87.53 wt% from 1 m3 wastewater. Decreasing chemical oxygen demand and electric conductivity of wastewater through freeze crystallization technology.
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Ácido Ascórbico/química , Ácido Ascórbico/aislamiento & purificación , Congelación , Aguas Residuales/química , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodos , Cristalización , Concentración de Iones de Hidrógeno , Hielo/análisis , Factores de TiempoRESUMEN
Aerobic granular sludge (AGS), which is formed by closely associating microorganisms through the production of extracellular polymeric substances (EPS), has proved to be an excellent and promising biosorbent. The reutilization of excess AGS as a kind of biosorbent would be an environmental-friendly means for heavy metal removal and reutilization of excess AGS. In this study, short-term exposure experiments were conducted to determine whether salinity (NaCl concentration ranged from 0 to 50â¯g/L) caused positive effects on Zn2+ adsorption performance by AGS. The results showed that the AGS formed in response to a 30â¯g/L saline treatment exhibited the best adsorption performance. Compared with the control (salinity of 0â¯g/L), the adsorptive capacity at equilibrium increased by 19.90% and reached 29.76â¯mg/g. The calculated maximum adsorption capacity in 30â¯g/L saline treatment group was 73.94â¯mg/g which was higher than described in previous studies using biochar, clarified sludge and aerobic granules. Analysis of EPS components suggested the enhanced adsorption of AGS might be ascribed to increasing polysaccharides content in the EPS after saline treatments. Additionally, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results indicated hydroxyl groups of EPS played an important role in Zn2+ binding. These findings provide further insight into the application of AGS for heavy metal adsorption.
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Salinidad , Aguas del Alcantarillado , Adsorción , Cloruro de Sodio , ZincRESUMEN
In order to understand multi-generational effects and changes of stress response by hexabromocyclododecane (HBCD) exposure, the animal model Caenorhabditis elegans was chosen for toxicity study. Multiple endpoints, including the physiological levels (growth, reproduction, and locomotion behaviors), stress-related gene expressions, reactive oxygen species (ROS) production and degree of cell apoptosis, were evaluated on exposed nematodes and their progeny. Prolonged exposure to HBCD at concentrations of 2â¯nM-200 nM caused adverse physiological effects in the parental generation (F0), and these effects were also observed in the oï¬spring under HBCD-free conditions (F1). HBCD-induced toxicities could be transferred from parent to oï¬spring. The integrated gene expressions proï¬les showed that exposure to HBCD at concentrations of 20-200â¯nM resulted in obvious changes in stress-related gene expressions, which were more increased in F0 generation than in F1 generation. The increased expressions were pronounced in several genes related to oxidative stress and cell apoptosis, e.g., hsp-16.2, hsp-16.48, sod-1, sod-3 and cep-1 genes. Exposure to 200â¯nM of HBCD could signiï¬cantly increase ROS production and degree of cell apoptosis in the F0 and F1 generations. Therefore, it was speculated that HBCD exposure induced oxidative stress and cell apoptosis, which resulted in the adverse physiological effects. This finding is helpful for understanding the multi-generational effects and evaluating the potential risk of HBCD.
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Caenorhabditis elegans , Hidrocarburos Bromados , Animales , Estrés Oxidativo , Especies Reactivas de OxígenoRESUMEN
Anaerobic ammonium oxidation (anammox) combined with partial-denitrification (NO3- â NO2-) is an innovative process for the simultaneous removal of ammonia and nitrate from wastewaters. An efficient method for the selection of partial denitrifying community, which relies on increasing influent salinity, is described. Using this method, a denitratating community was enriched, which showed a nitrite accumulation efficiency higher than 75% as well as a high nitrate conversion efficiency. Community analysis using 16S rDNA indicated that Halomonas became the dominant genus as salinity increased. Metagenomic analysis revealed that there was not a significant difference in reads mapping to downstream denitrification genes in a comparison of samples from cultures with 5% salinity to those without salinity. The majority of the reads mapping to the genes encoding dissimilatory nitrate and nitrite reductases nar and nirS came from Halomonas under high salinity conditions. Two metagenome-assembled genomes taxonomically assigned to Halomonas were obtained, one of which accounted for â¼35% of the reads under high salinity conditions. Both genomes harbored the genes for the complete denitrification pathway. These results indicate progressive onset denitrifiers, a phenotype where nitrite reduction only occurs after nitrate exhaustion, could be successfully enriched with increasing salinity. Progressive onset denitrifiers may be more widespread in natural and artificial habitats than anticipated and are shown here to be valuable for nitrogen mitigating processes.
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Nitritos , Salinidad , Reactores Biológicos , Desnitrificación , Nitrógeno , Oxidación-ReducciónRESUMEN
The moderately halophilic bacterium Virgibacillus halodenitrificans PDB-F2 copes with salinity by synthesizing or taking up compatible solutes. The main compatible solutes in this strain were ectoine and hydroxyectoine, as determined by (1)H nuclear magnetic resonance spectroscopy ((1)H-NMR). A high-performance liquid chromatography (HPLC) analysis showed that ectoine was the major solute that was synthesized in response to elevated salinity, while hydroxyectoine was a minor solute. However, the hydroxyectoine/ectoine ratio increased from 0.04 at 3 % NaCl to 0.45 at 15 % NaCl in the late exponential growth phase. A cluster of ectoine biosynthesis genes was identified, including three genes in the order of ectA, ectB, and ectC. The hydroxyectoine biosynthesis gene ectD was not part of the ectABC gene cluster. Reverse transcription-quantitative polymerase chain reactions (RT-qPCR) showed that the expression of the ect genes was salinity dependent. The expression of ectABC reached a maximum at 12 % NaCl, while ectD expression increased up to 15 % NaCl. Ectoine and hydroxyectoine production was growth phase dependent. The hydroxyectoine/ectoine ratio increased from 0.018 in the early exponential phase to 0.11 in the stationary phase at 5 % NaCl. Hydroxyectoine biosynthesis started much later than ectoine biosynthesis after osmotic shock, and the temporal expression of the ect genes differed under these conditions, with the ectABC genes being expressed first, followed by ectD gene. Increased culture salinity triggered ectoine or hydroxyectoine uptake when they were added to the medium. Hydroxyectoine was accumulated preferentially when both ectoine and hydroxyectoine were provided exogenously.
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Aminoácidos Diaminos/metabolismo , Presión Osmótica/fisiología , Cloruro de Sodio/farmacología , Virgibacillus/metabolismo , Aminoácidos Diaminos/genética , Regulación Bacteriana de la Expresión Génica , Salinidad , Tolerancia a la Sal/genética , Tolerancia a la Sal/fisiología , Estrés Fisiológico/fisiologíaRESUMEN
A rotating disk electrode (RDE) was used to investigate the concentration loss and impedance characteristics of anodic biofilms in microbial fuel cells (MFCs). Amperometric time-current analysis revealed that at the rotation rate of 480 rpm, a maximum current density of 168 µA cm(-2) can be achieved, which was 22.2 % higher than when there was no rotation. Linear sweep voltammetry and electrochemical impedance spectroscopy tests showed that when the anodic potential was set to -300 mV vs. Ag/AgCl reference, the power densities could increase by 59.0 %, reaching 1385 mW m(-2), the anodic resistance could reduce by 19 %, and the anodic capacitance could increase by 36 %. These results concur with a more than 85 % decrease of the diffusion layer thickness. Data indicated that concentration loss, diffusion layer thickness, and the mixing velocity play important roles in anodic resistance reduction and power output of MFCs. These findings could be helpful to the design of future industrial-scale MFCs with mixed bacteria biofilms.
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Fenómenos Fisiológicos Bacterianos , Fuentes de Energía Bioeléctrica/microbiología , Biopelículas , Impedancia Eléctrica , ElectrodosRESUMEN
Well dispersed TiO2 nanocrystals with (001) facets were successfully grown in situ on g-C3N4 through a facial solvothermal method. The resultant TiO2/g-C3N4 composites exhibit remarkably higher efficiency for photocatalytic degradation of phenol as compared to pure catalysts (g-C3N4 or TiO2) or mechanically mixed TiO2/g-C3N4. The optimal composite with 11.2 wt% TiO2 showed the highest degradation rate constant, which is 2.8 times that of pure g-C3N4, 2.2 times that of pure TiO2, and 1.4 times that of mechanically mixed TiO2/g-C3N4. The enhanced photocatalytic activity is mainly attributed to the effective charge separation derived from two aspects: (1) well matched energy levels between TiO2 and g-C3N4 and (2) a uniform and close contact between TiO2 and g-C3N4 that resulted from the in situ growth of highly dispersed TiO2 nanocrystals. The TiO2/g-C3N4 hybrid material prepared in this study is expected to provide a good foundation for the further design and synthesis of advanced TiO2/g-C3N4-based functional materials, and the in situ growth method developed is hopeful to provide a new strategy for the synthesis of other semiconductor-modified g-C3N4 materials.