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Biological treatment represents a fundamental component of wastewater treatment plants (WWTPs). The transmission of antibiotic resistance bacteria (ARB) and resistance genes (ARGs) occurred through the continuous migration and transformation, attributed to the residual presence of antibiotics in WWTPs effluent, posing a significant threat to the entire ecosystem. It is necessary to propose novel biological strategies to address the challenge of refractory contaminants, such as antibiotics, ARGs and ARB. This review summarizes the occurrence of antibiotics in wastewater, categorized by high and low concentrations. Additionally, current biological treatments used in WWTPs, such as aerobic activated sludge, anaerobic digestion, sequencing batch reactor (SBR), constructed wetland, membrane-related bioreactors and biological aerated filter (BAF) are introduced. In particular, because microorganisms are the key to those biological treatments, the effect of high and low concentration of antibiotics on microorganisms are thoroughly discussed. Finally, solutions involving functional bacteria, partial nitrification (PN)-Anammox and lysozyme embedding are suggested from the perspective of the entire biological treatment process. Overall, this review provides valuable insights for the simultaneous removal of antibiotics and ARGs in antibiotics wastewater.
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BACKGROUND AND AIM: Endotoxin-induced acute lung injury (ALI) is a complicated and fatal condition with no specific or efficient clinical treatments. 5-Methoxytryptophan (5-MTP), an endogenous metabolite of tryptophan, was revealed to block systemic inflammation. However, the specific mechanism by which 5-MTP affects ALI still needs to be clarified. The purpose of this study was to determine whether 5-MTP protected the lung by inhibiting NLRP3 inflammasome-mediated pyroptosis through the Nrf2/HO-1 signaling pathway. METHODS AND RESULTS: We used lipopolysaccharide (LPS)-stimulated C57BL/6 J mice and MH-S alveolar macrophages to create models of ALI, and 5-MTP (100 mg/kg) administration attenuated pathological lung damage in LPS-exposed mice, which was associated with decreased inflammatory cytokines and oxidative stress levels, upregulated protein expression of Nrf2 and HO-1, and suppressed Caspase-1 activation and NLRP3-mediated pyroptosis protein levels. Moreover, Nrf2-deficient mice or MH-S cells were treated with 5-MTP to further confirm the protective effect of the Nrf2/HO-1 pathway on lung damage. We found that Nrf2 deficiency partially eliminated the beneficial effect of 5-MTP on reducing oxidative stress levels and inflammatory responses and abrogating the inhibition of NLRP3-mediated pyroptosis induced by LPS. CONCLUSION: These findings suggested that 5-MTP could effectively ameliorate ALI by inhibiting NLRP3-mediated pyroptosis via the Nrf2/HO-1 signaling pathway.
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Lesão Pulmonar Aguda , Inflamassomos , Camundongos , Animais , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Triptofano/efeitos adversos , Endotoxinas/farmacologia , Lipopolissacarídeos/farmacologia , Piroptose , Camundongos Endogâmicos C57BL , Transdução de Sinais , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/metabolismoRESUMO
PURPOSE: Endotoxin-induced acute lung injury (ALI) is a severe disease caused by an imbalanced host response to infection. It is necessary to explore novel mechanisms for the treatment of endotoxin-induced ALI. In endotoxin-induced ALI, tetramethylpyrazine (TMP) provides protection through anti-inflammatory, anti-apoptosis, and anti-pyroptosis effects. However, the mechanism of action of TMP in endotoxin-induced ALI remains unclear. Here, we aimed to determine whether TMP can protect the lungs by inhibiting Golgi stress via the Nrf2/HO-1 pathway. METHODS AND RESULTS: Using lipopolysaccharide (LPS)-stimulated C57BL/6J mice and MLE12 alveolar epithelial cells, we observed that TMP pretreatment attenuated endotoxin-induced ALI. LPS + TMP group showed lesser lung pathological damage and a lower rate of apoptotic lung cells than LPS group. Moreover, LPS + TMP group also showed decreased levels of inflammatory factors and oxidative stress damage than LPS group (P < 0.05). Additionally, LPS + TMP group presented reduced Golgi stress by increasing the Golgi matrix protein 130 (GM130), Golgi apparatus Ca2+/Mn2+ ATPases (ATP2C1), and Golgin97 expression while decreasing the Golgi phosphoprotein 3 (GOLPH3) expression than LPS group (P < 0.05). Furthermore, TMP pretreatment promoted Nrf2 and HO-1 expression (P < 0.05). Nrf2-knockout mice or Nrf2 siRNA-transfected MLE12 cells were pretreated with TMP to explore how the Nrf2/HO-1 pathway affected TMP-mediated Golgi stress in endotoxin-induced ALI models. We observed that Nrf2 gene silencing partially reversed the alleviating effect of Golgi stress and the pulmonary protective effect of TMP. CONCLUSION: Our findings showed that TMP therapy reduced endotoxin-induced ALI by suppressing Golgi stress via the Nrf2/HO-1 signaling pathway in vivo and in vitro.
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Lesão Pulmonar Aguda , Pirazinas , Animais , Camundongos , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/metabolismo , Antioxidantes/metabolismo , Complexo de Golgi/metabolismo , Complexo de Golgi/patologia , Heme Oxigenase-1/genética , Lipopolissacarídeos/toxicidade , Pulmão/patologia , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/genética , Estresse Oxidativo , Transdução de Sinais , Pirazinas/farmacologiaRESUMO
Treating wastewater using purple non-sulfur bacteria (PNSB) is an environmentally friendly technique that can simultaneously remove pollutants and lead to the accumulation of high-value cell inclusions. However, no PNSB system for treating heavy oil refinery wastewater (HORW) and recovering high-value cell inclusions has yet been developed. In this study, five batch PNSB systems dominated by Rhodopseudomonas were used to treat real HORW for 186 d. The effects of using different hydraulic retention times (HRT), sludge retention times (SRT), trace element solutions, phosphate loads, and influent loads were investigated, and the bacteriochlorophyll, carotenoid, and coenzyme Q10 concentrations were determined. The community structure and quantity of Rhodopseudomonas in the systems were determined using a high-sequencing technique and quantitative polymerase chain reaction technique. The long-term results indicated that phosphate was the limiting factor for treating HORW in the PNSB reactor. The soluble chemical oxygen demand (SCOD) removal rates were 67.03% and 85.26% without and with phosphate added, respectively, and the NH4+-N removal rates were 32.18% and 89.22%, respectively. The NO3--N concentration in the effluent was stable at 0-3 mg/L with or without phosphate added. Adding phosphate increased the Rhodopseudomonas relative abundance and number by 13.21% and 41.61%, respectively, to 57.35% and 8.52 × 106 gene copies/µL, respectively. The SRT was the limiting factor for SCOD removal, and the bacteria concentration was the limiting factor for nitrogen removal. Once the inflow load had been increased, the total nitrogen (TN) removal rate increased as the HRT increased. Maximum TN removal rates of 64.46%, 68.06%, 73.89%, 82.15%, and 89.73% were found at HRT of 7, 10, 13, 16, and 19 d, respectively. The highest bacteriochlorophyll, carotenoid, and coenzyme Q10 concentrations were 2.92, 4.99, and 4.53 mg/L, respectively. This study provided a simple and efficient method for treating HORW and reutilizing resources, providing theoretical support and parameter guidance for the application of Rhodopseudomonas in treating HORW.
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Poluentes Ambientais , Rodopseudomonas , Águas Residuárias , Ubiquinona , Bacterioclorofilas , Esgotos , Carotenoides , Nitrogênio , Indústria de Petróleo e Gás , FosfatosRESUMO
Diradicals based on the Blatter units and connected by acetylene and alkene spacers have been prepared. All the molecules show sizably large diradical character and low energy singlet-triplet gaps. Their photo-physical properties concerning their lowest energy excited state have been studied in detail by steady-state and time-resolved absorption spectroscopy. We have fully identified the main optical absorption band and full absence of emission from the lowest energy excited state. A computational study has been also carried out that has helped to identify the presence of a conical intersection between the lowest energy excited state and the ground state which produces a highly efficient light-to-heat conversion of the absorbed radiation. Furthermore, an outstanding photo-thermal conversion 77.23 % has been confirmed, close to the highest in the diradicaloid field. For the first time, stable diradicals are applied to photo-thermal therapy of tumor cells with good stability and satisfactory performance at near-infrared region.
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In spite of the excellent electrochemical performance in lithium-ion batteries (LIBs), transition-metal compounds usually show inferior capacity and cyclability in sodium-ion batteries (SIBs), implying different reaction schemes between these two types of systems. Herein, coupling operando magnetometry with electrochemical measurement, we peformed a comprehensive investigation on the intrinsic relationship between the ion-embedding mechanisms and the electrochemical properties of the typical FeS2/Na (Li) cells. Operando magnetometry together with ex-situ transmission electron microscopy (TEM) measurement reveal that only part of FeS2 is involved in the conversion reaction process, while the unreactive parts form "inactive cores" that lead to the low capacity. Through quantification with Langevin fitting, we further show that the size of the iron grains produced by the conversion reaction are much smaller in SIBs than that in LIBs, which may lead to more serious pulverization, thereby resulting in worse cycle performance. The underlying reason for the above two above phenomena in SIBs is the sluggish kinetics caused by the larger Na-ion radius. Our work paves a new way for the investigation of novel SIB materials with high capacity and long durability.
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To explore the fate and spreading mechanism of antibiotics resistance genes (ARGs) in antibiotics wastewater system, a laboratory-scale (1.47 L) Expanded Granular Sludge Bed (EGSB) bioreactor was implemented. The operating parameters temperature (T) and hydraulic retention time (HRT) were mainly considered. This result showed the removal of ARGs and COD was asynchronous, and the recovery speed of ARGs removal was slower than that COD removal. The decreasing T was attributed to the high growth rate of ARGs host bacteria, while the shortened HRT could promote the horizontal and vertical gene transfer of ARGs in the sludge. The analysis result of potential bacterial host showed more than half of the potential host bacteria carried 2 or more ARGs and suggested an indirect mechanism of co-selection of multiple ARGs. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was used to investigate the functional characteristics of bacterial community. This result showed the bacterial functional genes contributed 40.41% to the abundance change of ARGs in the sludge, which was higher that of bacterial community. And the function genes of "aromatic hydrocarbon degradation", "Replication, recombination and repair proteins" and "Flagellar assembly" were mainly correlated with the transfer of ARGs in the sludge. This study further revealed the mechanism of ARGs spread in the EGSB system, which would provide new ideas for the development of ARGs reduction technology.
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Esgotos , Águas Residuárias , Antibacterianos/farmacologia , Bactérias/genética , Resistência Microbiana a Medicamentos/genética , FilogeniaRESUMO
In this study, one lab-scale EGSB reactor (1.47 L volume) was designed to treat the antibiotic wastewater under different environmental factors, including the addition of cephalexin (CFX), Temperature (T) and Hydraulic Retention Time (HRT). The microbial community structure in EGSB reactor was analyzed with high-throughput sequencing technology to investigate their response to environmental factors changes, and then the random-matrix-theory (RMT)-based network analysis was used to investigate the microbial community's molecular ecological network in EGSB systems treating antibiotics wastewater. Moreover, the explanatory value of each environmental factor on the change of microbial community structure was obtained through the result of redundancy analysis (RDA). The results showed that the addition of cephalexin (CFX), decline of T and decline of HRT (8 h) would decrease the removal efficiency of COD decreasing. And the removal efficiency of CFX would not be affected by decline of T and HRT, except the producing and degrading process of CFX by-products was changed obviously. The result of RDA analysis suggested the environmental factors mainly affected bacterial and fungal microbial community structure but not archaeal ones. The result of high-throughput sequencing showed the relative abundance (RA) of Firmicutes had been obviously affected by T and HRT, which might be main reason leading to the decrease of COD removal efficiency. In addition, molecular ecological network analysis showed the growth of Bacteroidetes occupied the niche of functional microorganism and led to the unstable operation of EGSB when T declined. What's more, the molecular ecological network analysis revealed that Exophiala which belonged to fungi Ascomycota phylum was the hub genus to degrade complex refractory organic pollutants, and Aceticlastic methanogens Methanosaeta was the core functional archaea genus.
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Antibacterianos/isolamento & purificação , Reatores Biológicos/microbiologia , Microbiota , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Antibacterianos/metabolismo , Archaea/classificação , Archaea/genética , Archaea/crescimento & desenvolvimento , Archaea/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Fungos/classificação , Fungos/genética , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Temperatura , Águas Residuárias/química , Poluentes Químicos da Água/metabolismoRESUMO
In order to realize the efficient and stable operation of anaerobic digestion for oxytetracycline (OTC) production wastewater which contains high concentration refractory organic matters and antibiotic residues, two laboratory-scale EGSB reactors (the experimental reactor and the control reactor) were constructed for pre-treating OTC production wastewater and the complex characteristics and connections among anaerobic fermentative bacteria, methanogens and fungi were analyzed. The experimental reactor gradually increased OTC doses of 0-200 mg/L by four phases compared with the control reactor which was fed without OTC addition during 280 days' operation. The average COD removal efficiency of 91.44% with the average OTC removal efficiency of 27.90% was achieved at OTC concentration of 200 mg/L. The addition of OTC did not affect the preponderant methanogen type, and Methanosaeta, a strict aceticlastic methanogen genus, was dominant both in working and controlling reactors on day 280. Redundancy analysis revealed that OTC and VFAs were the main environmental factors affecting the microbial communities and molecular ecological networks analysis indicated that the key genera principally belonged to Methanosaeta, Proteobacteria and Apiotrichum. Additionally, the fungi genus Apiotrichum might be related to the degradation of complex organic contaminants in OTC production wastewater treatment system.
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Microbiota , Oxitetraciclina , Purificação da Água , Anaerobiose , Reatores Biológicos , Esgotos , Eliminação de Resíduos Líquidos , Águas ResiduáriasRESUMO
A novel and simple method was established for the extraction and determination of seven compounds in Anemarrhena asphodeloides Bge. using silica gel-based vortex-homogenized matrix solid-phase dispersion and ultra-high performance liquid chromatography quadrupole-time of-flight mass spectrometer. The conditions for the extraction were optimized. Silica gel was used as the dispersant, 50% methanol-water was selected as an elution solvent and the grinding time was 3 min. Compared with the traditional ultrasonic-assisted extraction, the developed method was rapid and efficient. In order to screen potential antioxidants, extract dealing with the optimized method was applied to a polyamide chromatography column and a D-101 macroporous resin column. Fr.2.2 showed the highest antioxidant activities with the most content of flavonoid. A total of 25 peaks were identified from the active fraction. A 2,2'-diphenyl-1-picrylhydrazyl ultra-high performance liquid chromatography coupled with mass spectrometry approach was adopted for the rapid and exact screening and identification of antioxidant compounds. It indicated that flavonoids exhibited potential antioxidant activities. The antioxidant activities of nine monomeric compounds in vivo were tested. Structure-activity relationships were discussed. Five flavonoids with the concentration of 500 µg/mL would reduce the oxidative stress of PC12 cells that were induced with 2,2'-azobis[2-methylpropionamidine] dihydrochloride.
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Anemarrhena/química , Antioxidantes/análise , Flavonoides/análise , Extratos Vegetais/isolamento & purificação , Extração em Fase Sólida , Amidinas/antagonistas & inibidores , Amidinas/farmacologia , Animais , Antioxidantes/farmacologia , Relação Dose-Resposta a Droga , Flavonoides/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Células PC12 , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Ratos , Sílica Gel/químicaRESUMO
In the study, antibiotic resistance genes (ARGs) were examined in wastewater and sludge samples to explore the effect of cephalexin (CFX) on the spreading and removal of ARGs in the Expanded Granular Sludge Bed (EGSB) reactor treating antibiotics wastewater. The result showed that the addition of CFX in the wastewater affected the removal amount of ß-lactam ARGs and other types ARGs. Besides, the addition of CFX in the wastewater had no obviously effect on total concentration of targeted ARGs in the sludge, but it was related to the accumulation of some typical ARGs. Based on gene cassette array libraries analysis, the diversity of gene cassettes carried by intI1 gene was increased by the addition of CFX in the wastewater. Furthermore, the co-occurrence patterns between ARGs and bacterial genus were also investigated. The results showed the CFX in the wastewater not only affected the number of potential host bacteria of ARGs, but also changed the types of potential host bacteria of ARGs. The correlation analysis of ARG in influent, effluent and sludge showed that, for blaCTX-M, sul2, qnrS and AmpC genes, their removal amount in EGSB reactor treating antibiotic wastewater system might be enhanced by reducing their concentration in the sludge.
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Antibacterianos/farmacologia , Cefalexina/farmacologia , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/microbiologia , Antibacterianos/análise , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Cefalexina/análise , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos/efeitos dos fármacos , Esgotos/química , Esgotos/microbiologia , Águas Residuárias/químicaRESUMO
Global warming is becoming more severe. We here proposed an innovative green technique aimed at reducing the CH4 emissions from constructed wetlands (CWs) in which CH4 is controlled by microbial fuel cells (MFCs). The results of our work indicated that CH4 emissions from CWs could be controlled by operating MFC. The CH4 fluxes significantly decreased in the MFC-CW (close circuit CC) compared with the control MFC-CW (open circuit OC). The bioelectricity generation and COD removal rates also differed in the two systems. The highest power density (0.27 W m-3) and the lowest CH4 emissions (4.7 mg m-2 h-1) were observed in the CC system. The plants' effects on the performance of the MFC-CWs were also investigated. The plant species had a profound impact on the CH4 emissions and electricity production in MFC-CWs. The greatest CH4 flux (9.5 mg m-2 h-1) was observed from the MFC-CW planted with Typha orientalis, while the CH4 emissions from the MFC-CW planted with Cyperus alternifolius were reduced by 45%. Additional microbial processes were investigated. Quantitative real-time PCR (q-PCR) analysis indicated that the gene abundance of eubacterial 16 S rRNA, particulate methane monooxygenase (pmoA), and methyl coenzyme M reductase (mcrA) significantly differed for the control CW and MFC-CWs planted with different plants. In the CC systems, the mcrA genes in the anode were low, while the pmoA genes in the cathode were high. The operation of MFCs in CWs changed the exoelectrogenic and methanogenic community structures. Sequencing analysis indicated that phylotypes related to Geobacter, Bacteroides, and Desulfovibrio were specifically enriched in the CC systems. The results demonstrated that the operation of MFCs in the CWs resulted in the competition between the electrogenes and methanogenes, which resulted in distinctive microbial populations and biochemical processes that suppressed the CH4 emissions from the CWs.
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Fontes de Energia Bioelétrica , Eletricidade , Eletrodos , Águas Residuárias , Áreas AlagadasRESUMO
The volatile fatty acids (VFAs) accumulation pattern and microbial community succession were studied during excess sludge (ES) alkaline fermentation at pH of 10.0 with expanded granular sludge blanket reactor over 5 cyclers. Microbial community shifted conspicuously as ES suffered alkaline fermentation. Both VFAs and acid-producing bacteria increased rapidly during the first 8 days fermentation time, and they showed a quite positive correlation relationship. In addition, soluble chemical oxygen demand (SCOD) also dramatically increased during the first 8 days, which implied 8 day was the optimum sludge retention time (SRT) for ES alkaline fermentation and VFAs accumulation time. Illumina Miseq Sequencing analysis indicated that Clostridium, Bacillus, Amphibacillus and Peptostreptococcaceae were the dominant bacteria genus to produce VFAs. Acetic acid took about 84% in total VFAs because among the total acid-producing bacteria most bacteria could produce acetic acid.
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Ácidos Graxos Voláteis , Fermentação , Esgotos/química , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos , Concentração de Íons de HidrogênioRESUMO
This study aimed to reveal how amoxicillin (AMX) affected the microbial community and the spread mechanism of antibiotic resistance genes (ARGs) in the AMX manufacture wastewater treatment system. For this purpose, a 1.47 L expanded granular sludge bed (EGSB) reactor was designed and run for 241days treating artificial AMX manufacture wastewater. 454 pyrosequencing was applied to analyze functional microorganisms in the system. The antibiotic genes OXA-1, OXA-2, OXA-10, TEM-1, CTX-M-1, class I integrons (intI1) and 16S rRNA genes were also examined in sludge samples. The results showed that the genera Ignavibacterium, Phocoenobacter, Spirochaeta, Aminobacterium and Cloacibacillus contributed to the degradation of different organic compounds (such as various sugars and amines). And the relative quantification of each ß-lactam resistance gene in the study was changed with the increasing of AMX concentration. Furthermore the vertical gene transfer was the main driver for the spread of ARGs rather than horizontal transfer pathways in the system.
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Amoxicilina/farmacologia , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Genes Bacterianos , Águas Residuárias/microbiologia , Bactérias/genética , Eliminação de Resíduos Líquidos , Microbiologia da ÁguaRESUMO
This work investigated the effects of eight metal ions on Rhodopseudomonas palustris growth and 5-aminolevulinic acid (ALA) yield in wastewater treatment. Results show that metal ions (Mg(2+) of 15 mmol/L, Fe(2+) of 400 µmol/L, Co(2+) of 4 µmol/L, Ni(2+) of 8 µmol/L and Zn(2+) of 4 µmol/L) could effectively improve the chemical oxygen demand (COD) removal, Rp. palustris biomass and ALA yield. The highest ALA yield of 13.1 mg/g-biomass was achieved with Fe(2+) of 400 µmol/L. ALA yields were differentially increased under different metal ions in the following order: Fe(2+) group > Mg(2+) group > Co(2+) group = Ni(2+) group > Zn(2+) group = Mo(2+) group > control. Cu(2+) and Mn(2+) inhibited Rp. palustris growth and ALA production. Mechanism analysis revealed that metal ions changed ALA yields by influencing the activities of ALA synthetase and ALA dehydratase.
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Ácido Aminolevulínico/metabolismo , Metais/farmacologia , Rodopseudomonas/efeitos dos fármacos , Rodopseudomonas/metabolismo , Análise da Demanda Biológica de Oxigênio , Biomassa , Íons , Rodopseudomonas/crescimento & desenvolvimento , Águas ResiduáriasRESUMO
This study aimed at increasing carotenoid yield of Rhodobacter sphaeroides in wastewater treatment by adding magnesium ion (Mg(2+)). Results showed that Mg(2+) could improve R. sphaeroides biomass and carotenoid yield effectively. The highest carotenoid yield of 4.83 ± 0.14 mg/g biomass and biomass production of 3900 ± 180 mg/L were achieved at optimal Mg(2+) concentration of 15 mmol/L. Mechanism analysis revealed that Mg(2+) could promote carotenoid production by regulating the expressions of crt genes. Up-regulation of crtBDA genes improved carotenoid biosynthesis of R. sphaeroides.
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Carotenoides/genética , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Magnésio/farmacologia , Rhodobacter sphaeroides/efeitos dos fármacos , Rhodobacter sphaeroides/genética , Biomassa , Carotenoides/biossíntese , Águas Residuárias/microbiologiaRESUMO
To well understand the community structure and composition of mesophilic microorganisms in anaerobic system fed with PTA wastewater, an up-flow anaerobic fixed bed reactor was continuously run at 33 and 37 °C for 75 and 60 days, respectively. Both fluorescence in situ hybridization analysis and 454-pyrosequencing were applied to investigate the microbial distinction within mesophilic ranges. A preferable performance was achieved at 37 than 33 °C. The taxonomic complexities of two samples were further compared at phylum, class, and genus levels. Notably, microbial diversity differed a lot and the change of populations was observed mainly in the shared OTUs. Genus level analysis showed that when temperature was increased to 37 °C, the abundance of Thauera and Hydrogenophaga (ß-Proteobacteria) decreased by 93.75 and 61.47 %, respectively, whereas that of Syntrophorhabdus (δ-Proteobacteria) increased from 4.93 to 16.01 %. Furthermore, the dominant archaeal Methanobacterium at both temperatures indicated the prevailing contribution of hydrogenotrophic methanogens in mesophilic anaerobic system.
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Reatores Biológicos/microbiologia , Sequenciamento de Nucleotídeos em Larga Escala , Metagenoma , Microbiota , Águas Residuárias/microbiologia , Anaerobiose , Bactérias/classificação , Bactérias/genética , Hibridização in Situ Fluorescente , Filogenia , Esgotos/microbiologia , TemperaturaRESUMO
Bacillus thuringiensis/cereus L2 was added as a biostimulant to enhance the biomass accumulation and carotenoid yield of Rhodobacter sphaeroides using wastewater as the culturing medium. Results showed that biostimulation could significantly enhance the R. sphaeroides biomass production and carotenoid yield. The optimal biostimulant proportion was 40 µL (about 6.4×10(5) CFU). Through the use of biostimulation, chemical oxygen demand removal, R. sphaeroides biomass production, carotenoid concentration, and carotenoid yield were improved by 178%, 67%, 214%, and 70%, respectively. Theoretical analysis revealed that there were two possible reasons for such increases. One was that biostimulation enhanced the R. sphaeroides wastewater treatment efficiency. The other was that biostimulation significantly decreased the peroxidase activity in R. sphaeroides. The results showed that the highest peroxidase activity dropped by 87% and the induction ratio of the RSP_3419 gene was 3.1 with the addition of biostimulant. The enhanced carotenoid yield in R. sphaeroides could thus be explained by a decrease in peroxidase activity.
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Bacillus cereus/fisiologia , Bacillus thuringiensis/fisiologia , Carotenoides/biossíntese , Rhodobacter sphaeroides/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biomassa , Técnicas de Cocultura , Regulação Bacteriana da Expressão Gênica/fisiologia , Peroxidases/genética , Peroxidases/metabolismo , Rhodobacter sphaeroides/metabolismoRESUMO
5-Aminolevulinic acid (ALA), an important intermediate in tetrapyrrole biosynthesis in organisms, has been widely applied in many fields, such as medicine, agriculture, and the food industry, due to its biochemical characteristics. Research efforts supporting the microbial production of ALA have received increasing interest due to its dominant advantages over chemical synthesis, including higher yields, lesser pollutant emissions, and a lesser monetary cost. ALA synthesis using photosynthetic bacteria (PSB) is a promising approach in various microbial synthesis methods. In this review, recent advances on the microbial production of ALA with an emphasis on PSB are summarized, the key enzymes in the biosynthesis pathway (especially the relationship between key enzymes and key genes) are detailed, regulation strategies are described, and the significant influencing factors on the ALA biosynthesis and application of ALA are outlined. Furthermore, the eco-friendly perspective involving the combination of wastewater treatment and microbial production of ALA is conceived.
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Ácido Aminolevulínico/isolamento & purificação , Ácido Aminolevulínico/metabolismo , Bactérias/metabolismo , Biotecnologia/métodos , Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Redes e Vias Metabólicas/genética , Águas Residuárias/microbiologia , Purificação da Água/métodosRESUMO
This study provided insight into the characterization of secondary effluent from a wastewater treatment plant located in northeastern China. The secondary effluent was separated into three fractions, the dissolved, the near-colloidal and the suspended, to study their individual characteristics. It revealed that most of the organics in the secondary effluent existed in the dissolved form, accounting for 78.1-86.5% of the total chemical oxygen demand and 82.6-86.6% of the total organic carbon. Results from the molecular weight distribution study further indicated that organics with MW < 1k Da constituted 56.3-62.7% of total organics. Moreover, the particle size distribution study suggested that particles between 2.0 and 6.8 µm in diameter made up 80.0% of the total suspended solids. Both biological oxygen demand/chemical oxygen demand and biological dissolved organic carbon/dissolved organic carbon were measured ranging from 0.2 to 0.3, suggesting the most secondary effluent organics were biologically refractory. This conclusion was further strengthened by the functional groups information obtained from the GC/MS (gas chromatography/mass spectrometry) analysis. The characteristics information revealed from this study will help the design and selection of water quality-specific tertiary treatment technologies for secondary effluent water purification and reuse.