Cryomicroneedle delivery of nanogold-engineered Rhodospirillum rubrum for photochemical transformation and tumor optical biotherapy.

Tumor metabolite regulation is intricately linked to cancer progression. Because lactate is a characteristic metabolite of the tumor microenvironment (TME), it supports tumor progression and drives immunosuppression. In this study, we presented a strategy for antitumor therapy by developing a nanogold-engineered Rhodospirillum rubrum (R.r-Au) that consumed lactate and produced hydrogen for optical biotherapy. We leveraged a cryogenic micromolding approach to construct a transdermal therapeutic cryomicroneedles (CryoMNs) patch integrated with R.r-Au to efficiently deliver living bacterial drugs. Our long-term storage studies revealed that the viability of R.r-Au in CryoMNs remained above 90%. We found that the CryoMNs patch was mechanically strong and could be inserted into mouse skin. In addition, it rapidly dissolved after administering bacterial drugs and did not produce by-products. Under laser irradiation, R.r-Au effectively enhanced electron transfer through Au NPs actuation into the photosynthetic system of R. rubrum and enlarged lactate consumption and hydrogen production, thus leading to an improved tumor immune activation. Our study demonstrated the potential of CryoMNs-R.r-Au patch as a minimally invasive in situ delivery approach for living bacterial drugs. This research opens up new avenues for nanoengineering bacteria to transform tumor metabolites into effective substances for tumor optical biotherapy.

A Self-Assembled MOF-Escherichia Coli Hybrid System for Light-Driven Fuels and Valuable Chemicals Synthesis.

The development of semi-artificial photosynthetic systems, which integrate metal-organic frameworks (MOFs) with industrial microbial cell factories for light-driven synthesis of fuels and valuable chemicals, represents a highly promising avenue for both research advancements and practical applications. In this study, an MOF (PCN-222) utilizing racemic-(4-carboxyphenyl) porphyrin and zirconium chloride (ZrCl4) as primary constituents is synthesized. Employing a self-assembly process, a hybrid system is constructed, integrating engineered Escherichia coli (E. coli) to investigate light-driven hydrogen and lysine production. These results demonstrate that the light-irradiated biohybrid system efficiently produce H2 with a quantum efficiency of 0.75% under full spectrum illumination, the elevated intracellular reducing power NADPH is also observed. By optimizing the conditions, the biohybrid system achieves a maximum lysine production of 18.25 mg L-1, surpassing that of pure bacteria by 332%. Further investigations into interfacial electron transfer mechanisms reveals that PCN-222 efficiently captures light and facilitates the transfer of photo-generated electrons into E. coli cells. It is proposed that the interfacial energy transfer process is mediated by riboflavin, with facilitation by secreted small organic acids acting as hole scavengers for PCN-222. This study establishes a crucial foundation for future research into the light-driven biomanufacturing using E. coli-based hybrid systems.

Third-Trimester Maternal Serum Chemerin and Hypertension After Preeclampsia: A Prospective Cohort Study.

Background Limited data are available for postpartum hypertension prediction after preeclampsia. Methods and Results We examined the association between maternal serum chemerin levels in patients with preeclampsia and blood pressure (BP) levels after delivery in a prospective birth cohort of 15 041 singleton pregnant women. A total of 310 cases among 322 patients with preeclampsia (follow-up rate, 96.3%) were followed up during a mean 2.8 years after delivery. Compared with matched uncomplicated controls (n=310), serum chemerin measured at ≈35 gestational weeks was significantly increased in preeclampsia (171.8±49.2 versus 140.2±53.5 ng/mL; P<0.01) and positively correlated with the occurrence of postpartum hypertension, defined as either BP ≥130/80 mm Hg (per 1-SD increase: odds ratio [OR], 4.01 [95% CI, 2.77-5.81]) or as BP ≥140/90 mm Hg (per 1-SD increase: OR, 1.70 [95% CI, 1.28-2.25]) in patients with preeclampsia. The addition of chemerin levels improved the predictive performance of the clinical variable-derived prediction models for postpartum hypertension (for BP ≥130/80 mm Hg: area under the curve, 0.903 [95% CI, 0.869-0.937], Δ area under the curve, 0.070, P<0.001; for BP ≥140/90 mm Hg: area under the curve, 0.852 [95% CI, 0.803-0.902], Δ area under the curve, 0.030, P=0.002). The decision curve analysis revealed a net benefit of the chemerin-based prediction model for postpartum BP ≥130/80 mm Hg. Conclusions This study provides the first evidence supporting the independent predictive role of third-trimester maternal chemerin levels for postpartum hypertension after preeclampsia. Future study is warranted for external validation of this finding.

L-Citrulline Supplementation Restrains Ferritinophagy-Mediated Ferroptosis to Alleviate Iron Overload-Induced Thymus Oxidative Damage and Immune Dysfunction.

L-citrulline (L-cit) is a key intermediate in the urea cycle and is known to possess antioxidant and anti-inflammation characteristics. However, the role of L-cit in ameliorating oxidative damage and immune dysfunction against iron overload in the thymus remains unclear. This study explored the underlying mechanism of the antioxidant and anti-inflammation qualities of L-cit on iron overload induced in the thymus. We reported that L-cit administration could robustly alleviate thymus histological damage and reduce iron deposition, as evidenced by the elevation of the CD8+ T lymphocyte number and antioxidative capacity. Moreover, the NF-κB pathway, NCOA4-mediated ferritinophagy, and ferroptosis were attenuated. We further demonstrated that L-cit supplementation significantly elevated the mTEC1 cells' viability and reversed LDH activity, iron levels, and lipid peroxidation caused by FAC. Importantly, NCOA4 knockdown could reduce the intracellular cytoplasmic ROS, which probably relied on the Nfr2 activation. The results subsequently indicated that NCOA4-mediated ferritinophagy was required for ferroptosis by showing that NCOA4 knockdown reduced ferroptosis and lipid ROS, accompanied with mitochondrial membrane potential elevation. Intriguingly, L-cit treatment significantly inhibited the NF-κB pathway, which might depend on restraining ferritinophagy-mediated ferroptosis. Overall, this study indicated that L-cit might target ferritinophagy-mediated ferroptosis to exert antioxidant and anti-inflammation capacities, which could be a therapeutic strategy against iron overload-induced thymus oxidative damage and immune dysfunction.

Enhanced CO2 reduction and acetate synthesis in autotrophic biocathode by N-Hexanoyl-L-homoserine lactone (C6HSL)-based quorum-sensing regulation.

The aim of this study was to investigate the ecological role of quorum-sensing signaling molecule on the autotrophic biocathode for CO2 reduction and acetate synthesis. As a typical quorum-sensing signaling molecule, N-Hexanoyl-L-homoserine lactone (C6HSL) was used to regulate the construction of cathode biofilm. Results showed that the maximum acetate production from CO2 reduction improved by 94.8%, and the maximum Faraday efficiency of the microbial electrosynthesis system enhanced by 71.7%, with the regulation of C6HSL. Electrochemical analyses indicated that higher electrochemical activity and lower charge resistance of biocathode were obtained with C6HSL than without C6HSL. Confocal laser scanning microscopy and electron inhibitor experiment suggested that exogenous C6HSL increased living biomass in the biofilm and facilitated the electron transfer pathway related to NADH dehydrogenase-CoQ and proton motive force. With the C6HSL regulation, the relative abundance of hydrogen producers (e.g., Desulfovibrio and Desulfomicrobium) increased, contributing to the improved performance of autotrophic biocathode.

Enhanced sulfur recovery and sulfate reduction using single-chamber bioelectrochemical system.

The aim of this study was to investigate the feasibility of sulfate removal and elemental sulfur (S0) recovery in the single-chamber bioelectrochemical system (S-BES). The performance of S-BES was compared with that of dual-chamber bioelectrochemical system (D-BES). The S-BES was constructed with graphite felt as the anode and graphite brush as the cathode. The D-BES was constructed with proton exchange membrane as the separator between anode and cathode chambers. With an applied voltage of 1.0 V and 1 g/L acetate as the substrate, the S-BES and D-BES were tested by feeding with 480 mg/L SO42- in the phosphate buffer. Results showed that the maximum current density of 37.6 ± 4.5 mA/m3 was reached in the S-BES, which was higher than that in the D-BES (i.e., 22.2 ± 2.6 mA/m3). The SO42- removal was much higher in the S-BES than in the D-BES (99.5% vs. 57.2%). In the effluent and the electrodes of S-BES, S0 was identified with Raman and X- Ray diffraction analyses. The S0 recovery on the anode was 13.7 times of that on the cathode of S-BES, indicating that S0 was mainly produced on the anode. The measured total S0 recovery reached 67.5% in the S-BES. High relative abundance of Desulfurella (47.1%) and Geobacter (26.1%) dominated the community in the anode biofilm of S-BES. The excellent performance of S-BES may be attributed to the neutral pH in the solution and the synergistic reaction between the anode and cathode. Results from this study should be useful to enhance the S-BES applications in treating wastewater containing sulfate.

The Male-Biased Expression of miR-2954 Is Involved in the Male Pathway of Chicken Sex Differentiation.

Many expression data showed miRNAs have a potential function on regulating gonadal differentiation in animals, but their function is rarely studied in vivo, especially in chickens. Using the comprehensive expression profiles analysis, the specific male-biased miR-2954, which is significantly higher expressed in male embryos and gonads at all detected stages, was firstly screened during the early stages of chicken embryogenesis and gonadogenesis. In sex-reversed female gonads treated with aromatase inhibitors, the expression of miR-2954 was increased, which was consistent with the up-regulation of DMRT1 and SOX9. The injection of vivo-morpholino of miR-2954 significantly inhibited the expression of miR-2954 in chicken embryos, and the down-regulation of miR-2954 decreased the expression of testis-associated genes DMRT1 and SOX9, while the expression of ovary-associated genes and the gonadal morphology did not change obviously. These results confirm that miR-2954 coincides with testicular differentiation in chicken embryos, but whether it might be an upstream cell autonomous factor to sex development in birds still need to be further determined.

Male-Biased gga-miR-2954 Regulates Myoblast Proliferation and Differentiation of Chicken Embryos by Targeting YY1.

Previous studies have shown that gga-miR-2954 was highly expressed in the gonads and other tissues of male chickens, including muscle tissue. Yin Yang1 (YY1), which has functions in mammalian skeletal muscle development, was predicted to be a target gene of gga-miR-2954. The purpose of this study was to investigate whether gga-miR-2954 plays a role in skeletal muscle development by targeting YY1, and evaluate its function in the sexual dimorphism development of chicken muscle. Here, all the temporal and spatial expression profiles in chicken embryonic muscles showed that gga-miR-2954 is highly expressed in males and mainly localized in cytoplasm. Gga-miR-2954 exhibited upregulated expression of in vitro myoblast differentiation stages. Next, through the overexpression and loss-of-function experiments performed in chicken primary myoblasts, we found that gga-miR-2954 inhibited myoblast proliferation but promoted differentiation. During myogenesis, gga-miR-2954 could suppress the expression of YY1, which promoted myoblast proliferation and inhibited the process of myoblast cell differentiation into multinucleated myotubes. Overall, these findings reveal a novel role of gga-miR-2954 in skeletal muscle development through its function of the myoblast proliferation and differentiation by suppressing the expression of YY1. Moreover, gga-miR-2954 may contribute to the sex difference in chicken muscle development.

Bioremediation of Crude Glycerol by a Sustainable Organic-Microbe Hybrid System.

Klebsiella pneumoniae with crude glycerol-utilizing and hydrogen (H2)-producing abilities was successfully isolated from return activated sludge from Shatin Sewage Treatment Works. The H2 production strategy used in this study was optimized with crude glycerol concentrations, and 1,020 µmol of H2 was generated in 3 h. An organic-microbe hybrid system was constructed with metal-free hydrothermal carbonation carbon (HTCC) microspheres to enhance the H2 production under visible light (VL) irradiation. Under optimized VL intensity and HTCC concentration, an elevation of 35.3% in H2 production can be obtained. Electron scavenger study revealed that the photogenerated electrons (e-) from HTCC contributed to the additional H2 production. The variation in intercellular intermediates, enzymatic activity, and reducing equivalents also suggested that the photogenerated e- interacted with K. pneumoniae cells to direct the metabolic flux toward H2 production. This study demonstrated the feasibility of using an organic-microbe hybrid system as a waste-to-energy technology.

Hydrogen production in single-chamber microbial electrolysis cell under high applied voltages.

The aim of this study was to investigate the performance of single-chamber MEC under applied voltages higher than that for water electrolysis. With different acetate concentrations (1.0-2.0 g/L), the MEC was tested under applied voltages from 0.8 to 2.2 V within 2600 h (54 cycles). Results showed that the MEC was stably operated for the first time within 20 cycles under 2.0 and 2.2 V, compared with the control MEC with significant water electrolysis. The maximum current density reached 27.8 ± 1.4 A/m2 under 2.0 V, which was about three times as that under 0.8 V. The anode potential in the MEC could be kept at 0.832 ± 0.110 V (vs. Ag/AgCl) under 2.2 V, thus without water electrolysis in the MEC. High applied voltage of 1.6 V combined with alkaline solution (pH = 11.2) could result in high hydrogen production and high current density. The maximum current density of MEC at 1.6 V and pH = 11.2 reached 42.0 ± 10.0 A/m2, which was 1.85 times as that at 1.6 V and pH = 7.0. The average hydrogen content reached 97.2% of the total biogas throughout all the cycles, indicating that the methanogenesis was successfully inhibited in the MEC at 1.6 V and pH = 11.2. With high hydrogen production rate and current density, the size and investment of MEC could be significantly reduced under high applied voltages. Our results should be useful for extending the range of applied voltages in the MEC.

African Swine Fever Virus MGF360-12L Inhibits Type I Interferon Production by Blocking the Interaction of Importin α and NF-κB Signaling Pathway.

African swine fever (ASF) is an infectious transboundary disease of domestic pigs and wild boar and spreading throughout Eurasia. There is no vaccine and treatment available. Complex immune escape strategies of African swine fever virus (ASFV) are crucial factors affecting immune prevention and vaccine development. MGF360 genes have been implicated in the modulation of the IFN-I response. The molecular mechanisms contributing to innate immunity are poorly understood. In this study, we demonstrated that ASFV MGF360-12L (MGF360 families 12L protein) significantly inhibited the mRNA transcription and promoter activity of IFN-ß and NF-κB, accompanied by decreases of IRF3, STING, TBK1, ISG54, ISG56 and AP-1 mRNA transcription. Also, MGF360-12L might suppress the nuclear localization of p50 and p65 mediated by classical nuclear localization signal (NLS). Additionally, MGF360-12L could interact with KPNA2, KPNA3, and KPNA4, which interrupted the interaction between p65 and KPNA2, KPNA3, KPNA4. We further found that MGF360-12L could interfere with the NF-κB nuclear translocation by competitively inhibiting the interaction between NF-κB and nuclear transport proteins. These findings suggested that MGF360-12L could inhibit the IFN-I production by blocking the interaction of importin α and NF-κB signaling pathway, which might reveal a novel strategy for ASFV to escape the host innate immune response.

Carbon quantum dots-decorated TiO2/g-C3N4 film electrode as a photoanode with improved photoelectrocatalytic performance for 1,4-dioxane degradation.

In this study, carbon quantum dots (CQDs) were used to decorate a TiO2/g-C3N4 (TCN) film electrode. The morphological, optical, and electrochemical properties of the TiO2/g-C3N4/CQDs nanorod arrays (TCNC NRAs) film were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and electrochemical impedance spectroscopy (EIS). The improved optical properties, photoelectrochemical properties and photoelectrocatalytic (PEC) performance of photoanode can be observed by doping CQDs onto the TCN NRAs film. Compared with TiO2 NRAs and TCN NRAs, the narrower band gap of 2.47 eV and longer lifetime of photoinduced electron-hole pairs were observed in the TCNC NRAs. Under visible light irradiation and a bias voltage of 1.2 V, the photocurrent density and 1,4-dioxane (1,4-D) removal rate of PEC process with TCNC NRAs electrode reached 0.16 mA/cm2 and 77.9%, respectively, which was 2.5 times and 1.5 times of that with TCN NRAs electrode. TCNC NRAs electrode could keep >75% of the 1,4-D removal rate during five cycles tests. High PEC performance with TCNC NRAs electrode could be attributed to the enhanced charge separation and the change of electron transfer mechanism from typical heterojunction to Z-scheme, which may increase the active species production and change the dominant reactive species from O2·- to ·OH. Our experimental results should be useful for studying the degradation of 1,4-D and developing efficient PEC materials.

Sulfate reduction and elemental sulfur recovery using photoelectric microbial electrolysis cell.

Elemental sulfur recover from sulfate-rich environment has great significance for the sustainable development of environment and energy. This study aimed to realize simultaneous sulfate reduction and elemental sulfur recovery using a novel photoelectricity microbial electrolysis cell (PMEC) under low applied voltages. At an applied voltage of 1.2 V, the sulfate reduction rate in the PMEC reached 200 ± 2.3 mg L-1 d-1, and 46.3 ± 7.9% of the reduced sulfate converted to elemental sulfur. With increasing voltages from 0.8 to 1.5 V, the sulfate reduction rates enhanced from 37.8 ± 12.4 to 236 ± 18.1 mg L-1 d-1. The recovery efficiency of elemental sulfur from removed sulfate decreased to 35% at 1.5 V, which was attributed to the higher concentration of dissolved oxygen diffusing from the anode side. Sulfate reducing bacteria (including Desulfovibrio and Desulfomicrobium) cooperated with sulfur oxidizing bacteria (including Thiomonas and Acinetobacter) for recovering elemental sulfur that could be regulated by cathode configuration. The study provided an alternative to apply solar energy in biological sulfur recovery and reduce energy consumption of wastewater treatment.

Enhanced electron transfer on microbial electrosynthesis biocathode by polypyrrole-coated acetogens.

Extracellular electron transfer (EET) is a significant pathway to transport electrons between bacteria and electrode in microbial electrosynthesis systems (MESs). To enhance EET in the MES, a high-conductivity polymer, polypyrrole (PPy), was coated on the surface of mixed culture acetogens in situ and the PPy-coated bacteria were inoculated on the cathode of MES. The charge transfer resistance of PPy-coated biocathode was 33%-70% of that with PPy-uncoated. Acetate production rate and Faradic efficiency in PPy-coated biocathodes increased by 3 to 6 times. After 960 h operation, Acetobacterium, Desulfovibrio, and Acinetobacter dominate the community on the coated and uncoated biocathode. Quinone loop and NADH dehydrogenase to ubiquinone were involved in electron transfer pathway of biocathode and stimulated by PPy coating. Low-level expression of C-type cytochromes on biocathode indicated its less important role in inward EET. The study provided useful information for applications of high-conductivity chemicals in microbial electrosynthesis.

Hydrogen production from natural organic matter via cascading oxic-anoxic photocatalytic processes: An energy recovering water purification technology.

Photocatalysis provides a "green" strategy to produce the clean energy of H2. However, the realization of efficient H2 production is usually accomplished by the consumption of electron donors, which are costly energy carriers themselves. Here, we attempted to utilize the naturally abundant humic acid (HA), a representative natural organic matter (NOM), as the source of electron donor in a cascading oxic-anoxic photocatalytic system. Results showed that degradation of HA and remarkable H2 yield (1660.9 µmol g-1 h-1 at optimal condition) were obtained successively, whereas the anoxic photocatalytic treatment of pristine HA did not improve H2 yield but substantially eliminated the H2 production and HA degradation efficiency. These phenomena suggested the preoxidation process played a vital role in counteracting the detrimental effect of HA on photocatalytic H2 production. Electrochemical measurement indicated that the preoxidized HA harbored more redox-active moieties than the untreated HA and thus leading to a higher photo-induced charge carrier separation efficiency. A variety of advanced spectroscopic analyses revealed that the photocatalytic oxic pre-treatment resulted in breakdown of chemically inert, electron mediating and chromophoric aromatic macrostructure of HA to form smaller sized oxygenated organic intermediates. These intermediates were more nucleophilic than the pristine HA and acted as sacrificial reagent in the subsequent anoxic process for boosting H2 production. This study showcases an energy recovering water remediation process and paves the way for the design of novel photocatalytic technologies for environmental application.

Activated FXR promotes xenobiotic metabolism of T-2 toxin and attenuates oxidative stress in broiler chicken liver.

The transmission of T-2 toxin and its metabolites into the edible tissues of poultry has potential effects on human health. The bile acid and xenobiotic system composes an intricate physiological network of chemoprotective and transporter-related functions, which ensures the detoxification and removal of harmful xenobiotic and endobiotic compounds from the body. This study revealed that cholic acid (CA), as one of the bile acids, promoted the metabolism of T-2 toxin in vivo by inducing the xenobiotic metabolism enzymes expression, thereby increasing the stress resistance and attenuating the oxidative stress. This study also indicated that dietary supplementation of 1% CA alleviated the mortality caused by T-2 toxin. Liver histology results demonstrated that CA supplementation significantly reduced inflammatory cell infiltration, sinusoidal expansion and congestion. Biochemistry results showed that the elevations of plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and the increase in concentration of hydrogen peroxide (H2O2) in liver induced by the T-2 toxin were decreased by dietary supplementation of 1% CA. Additionally, CA supplementation led to the increase in superoxide dismutase (SOD) activity, but the decrease in catalase (CAT) activity in broiler chicken livers. Based on these findings, we propose that activation of FXR promotes T-2 toxin xenobiotic metabolism, and FXR plays a hepatoprotection role in liver injury induced by T-2 toxin.

Transport stress induces pig jejunum tissue oxidative damage and results in autophagy/mitophagy activation.

Pig transportation is associated with intestinal oxidative stress and results in destruction of intestinal integrity. Autophagy has been contributed to maintain cell homeostasis under stresses. The purpose of this study was to evaluate the effects of transport stress on morphology, intestinal mucosal barrier and autophagy/mitophagy levels in pig jejunum. A total of 16 finishing pigs were randomly divided into two groups. The control group was directly transported to the slaughterhouse and rested for 24 hr. The experimental groups were transported for 5 hr and slaughtered immediately. The results showed that transportation induced obvious stress responses with morphological and histological damage in jejunum accompanying with an elevated level of malondialdehyde (MDA; p < .05), endotoxin (LPS; p < .05), lactic dehydrogenase (LDH; p < .05) and a decreased level of serum superoxide dismutase (SOD; p < .05). Also, hemeoxy genase 1 (HO-1; p < .01) as well as tight junction protein (claudin-1 [p < .001], occludin [p < .05] and zonula occludens 1 [ZO-1; p < 0.05]) levels were attenuated in jejunum tissue, and NADPH oxidase 1 (NOX1; p < .01) mRNA expression was up-regulated. Further research indicated that transport stress could induce autophagy through increasing microtubule-associated protein light chain 3 (LC3; p < .05) and autophagy-related gene 5 (ATG5; p < .01) levels and suppressing p62 expression. Additionally, transport stress increased the protein levels of PTEN-induced putative kinase 1 (PINK1; p < .05) and Parkin (p < .05) which was associated with mitophagy. In conclusions, transport stress could induce the destruction of intestinal integrity and involve in the intestinal mucosal barrier oxidative damage, and also contribute to activation of autophagy/mitophagy.

[Impact Mechanisms of Carboxyl Group Modified Cathode on Acetate Production in Microbial Electrosynthesis Systems].

Microbial electrosynthesis systems (MESs) can convert carbon dioxide into added value compounds using microorganisms as catalyst, which is expected to help achieve conversion of greenhouse gases into resources. However, the synthetic efficiency of MESs is far behind the industry requirements. In this study, carbon cloth surfaces were bonded with carboxyl groups by electrochemical reduction of aryl diazonium salts and then used as a cathode in MESs reactors. The results showed that the hydrophilicity of the carbon cloth surfaces improved after the carboxyl groups were modified. However, weaker current of cyclic voltammetry was obtained in the modified cathode. Significant differences were observed between modified (CA-H, CA-M, CA-L) and non-modified cathode (CK) during the start-up period. After 48h, the hydrogen production rate of CA-H, CA-M, CA-L was 21.45, 28.60, and 22.75 times higher than CK. After 120h, the acetate accumulation concentration of CA-H, CA-M, CA-L was 2.01, 2.43, and 1.44 times higher than CK. After 324h, there was little difference in the electrochemical activity of cathodic biofilm and protein content (about 0.47 mg·cm-2) in all groups. The analysis of the community structure of cathodic biofilm showed that, in the genus level, Acetobacterium, Norank_p_Saccharibacteria, and Thioclava were the dominant species, accounting for 59.6% to 82.1%. There was little difference in the relative abundance of Acetobacterium in all groups (31.3% to 40.1%). However, the relative abundance of norank_p_Saccharibacteria in CA-H, CA-M, CA-L, and CK were 16.1%, 24.6%, 31.1%, and 37.5%, respectively. The carboxyl modified cathode had a great influence on the start-up stage of MESs, which could be a new idea for the rapid start-up of MESs.

Efficient reduction of nitrobenzene by sulfate-reducer enriched biocathode in microbial electrolysis cell.

This study aimed to enhance treatment of wastewater containing nitrobenzene (NB) and sulfate using biocathode enriched with sulfate-reducing bacteria in microbial electrolysis cell (MEC). Artificial wastewater with 50 mg L-1 NB and 200 mg L-1 sulfate was used as the catholyte. With 0.8 V applied voltage, removal efficiencies of NB and sulfate reached 98% and 34%, respectively, within 36 h. Aniline and sulfide were the main reductive products in the catholyte with concentrations increased to 0.32 and 0.51 mM, which accounted for 97% and 78% of the removed NB and sulfate, respectively. Sulfate-reducer Desulfovibrio sp. and Wolinella sp. played the dominant role in the biocathode for the reductions of sulfate and NB. Analyses of scanning electron microscope and X-ray photoelectron spectroscopy showed the formation of elemental S on the biocathode surface. The relative abundance of sulfur-oxidizing bacterium Thioclava sp. reached 24% on the biocathode. The results indicated that the oxidation process from S2- to S0 occurred on the biocathode, which provided electrons to biofilm for NB reduction. The MEC with sulfate-reducer enriched biocathode can be used as an alternative to treat complex wastewater containing NB and sulfate.

Enhanced sulfate reduction accompanied with electrically-conductive pili production in graphene oxide modified biocathodes.

This study aimed to investigate the graphene oxide (GO) conversion by the sulfate-reducing biocathode and its modified effects on performance of the microbial electrolysis cell (MEC). Biocathodes were acclimated with autotrophic sulfate-reducing cultures using medium containing 500 mg L-1 sulfate. Sulfate reductive rate in the MEC was 230 and 135 g m-3 d-1, respectively, with and without 30 mg L-1 GO addition. Raman measurements showed that GO was efficiently reduced to graphene by the biocathode within 24 h. Higher electrochemical activity and smaller charge transfer resistance were detected on biofilm with GO affected. With high electrical conductivity of 307 ±â€¯36 µS cm-1, pili substance were observed on GO affected biofilm. As dominated by Desulfovibrio sp., the biocathode could use GO as the sole electron acceptor and maintained high activity. The results from this study should provide useful information for applications of nanomaterials in the biocathode MEC.