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N2O (Nitrous oxide, a booster oxidant in rockets) has attracted increasing interest as a means of enhancing energy production, and it can be produced by nitrate (NO3−) reduction in NO3−-loading wastewater. However, conventional denitrification processes are often limited by the lack of bioavailable electron donors. In this study, we innovatively propose a self-photosensitized nonphototrophic Thiobacillus denitrificans (T. denitrificans-CdS) that is capable of NO3− reduction and N2O production driven by light. The system converted >72.1 ± 1.1% of the NO3−-N input to N2ON, and the ratio of N2O-N in gaseous products was >96.4 ± 0.4%. The relative transcript abundance of the genes encoding the denitrifying proteins in T. denitrificans-CdS after irradiation was significantly upregulated. The photoexcited electrons acted as the dominant electron sources for NO3− reduction by T. denitrificans-CdS. This study provides the first proof of concept for sustainable and low-cost autotrophic denitrification to generate N2O driven by light. The findings also have strong implications for sustainable environmental management because the sunlight-triggered denitrification reaction driven by nonphototrophic microorganisms may widely occur in nature, particularly in a semiconductive mineral-enriched aqueous environment. Keywords: Biohybrid system, Autotrophic denitrification, Semiconductors, Cadmium sulfide, Nitrous oxide

The development of microbial electrosynthesis (MES) for renewable electricity-driven bioutilization of CO2 has recently attracted considerable interest due to its ability to synthesize chemicals with the transition towards a circular carbon economy. However, the increase of acetate production and the decrease of energy consumption of MES using an advanced reactor design have received less attention. In this study, the total acetate production rate using novel flow-electrode MES reactors ((16 ± 1) g·m−2·d−1) was double that using reactors without powder activated carbon (PAC) amendment ((8 ± 3) g·m−2·d−1). The flow-electrode MES reactors had a Coulombic efficiency of 43.5% ± 3.1%, an energy consumption of (0.020 ± 0.005) kW·h·g−1, and an energy efficiency of 18.7% ± 1.3% during acetate production. The flow-electrode with PAC amendment could decrease the net water flux and charge transfer resistance, while had little impact on the cell voltage, rheological behavior, and acetate adsorption. In the flow-electrode MES reactors, the expression of genes involving in energy production and conversion were increased, and the increase of acetate production was found correlated with the increased abundance of Acetobacterium. The Wood–Ljungdahl pathway (WLP) and reductive citric acid cycle (rTCA) were found to be the pathways responsible for carbon fixation. The concentrations of acetate in the stacked flow-electrode MES reached 7.0 g·L−1. This study presents a new approach for the construction of scalable MES reactors with high-performance chemical generation and CO2 utilization.

Li7La3Zr2O12 (LLZO) garnets are one of the most promising solid electrolytes for next generation all-solid-state Li metal batteries due to their high ionic conductivities, chemical stabilities to metallic lithium and wide electrochemical window. Single and co-doped LLZO with Ga, Al, Nb were prepared by solid state reaction and sintered under oxygen atmosphere. Lithium ion conduction properties were investigated through electrochemical impedance spectroscopy in the temperature range of −25 °C–45 °C. Among the doped compositions, Ga doped single phase cubic LLZO shows the highest ionic conductivity of 1.49 × 10−3 S/cm at room temperature and activation energy of 0.27eV, which is one of the best results reported in literature so far in terms of doped garnet structured LLZO. All single or co-doped LLZO samples exhibit low electronic conduction which are 4–5 orders of magnitude lower than their corresponding ionic conductivities. Ga-doped garnet LLZO of high ionic conductivity and negligible electronic conduction makes it a superior solid electrolyte for all-solid-state Li metal batteries.

Microbial electrochemical sensor has been regarded as a promising technology for water biotoxicity monitoring, while its practical application is partially restricted by the requirement of organic substrate or power supply in real time. In the present study, rechargeable microbial electrochemical sensors were constructed, with the ex-situ preparation of bioanode and the in-situ preparation of biocathode. Acetate, formate, and hydrogen were identified as the charge carriers, and a Coulombic efficiency of 38% ± 18% and an energy efficiency of 2.2% ± 0.7% were obtained. The increase of charge current could decrease the energy efficiency as well as maximum acetate accumulation, while increase the H2 component. The increase of discharge resistor could enhance the energy efficiency, while had little impact on the Coulombic efficiency. Good reusability of rechargeable biosensors was observed with an injection of formaldehyde from 0% to 0.05%, but the sensors could not be fully recovered after the injection of 0.1% formaldehyde. The exposure of formaldehyde could affect the relative abundance of Acetobacterium, Acetoanaerobium, and Geobacter. When an abiotic cathode was used, the formate and hydrogen produced during the charging process were converted into acetate as an intermediate product during the discharging process. This study demonstrates the potential of the rechargeable microbial electrochemical system as a novel sensor for water biotoxicity monitoring.

Abstract In this study, Tisochrysis lutea was cultivated in mixotrophic and heterotrophic cultures with glycerol as a carbon source and with glucose and acetate for comparison; autotrophic cultivation was the control group without a carbon source. It was found that T. lutea used glycerol and did not use glucose and acetate under mixotrophy. Mixotrophy slightly elevated the docosahexaenoic acid (DHA) and total fatty acids (TFA) content in the dry-weight and enhanced the DHA and TFA production in medium (41.3 and 31.9% respectively) at the end of a 16-day cultivation, while heterotrophy reduced the DHA content and TFA production. Under the mixotrophy, the glycerol contribution to the DHA production (16.19 mg/L) and the TFA production (97.8 mg/L) was not very high and the DHA yield [2.63% chemical oxygen demand (COD)] and TFA yield (13.1% COD) were also very low. Furthermore, T. lutea using glycerol had a period of adaptation, indicating that T. lutea was not an ideal microalga for organic carbon utilization.

A 67-year-old woman with end-stage renal disease (ESRD) was referred with chronic diarrhoea, severe hypokalaemia and recurrent colonic pseudo-obstructions following haemorrhagic shock. The cause of secretory diarrhoea was uncertain, but an ileostomy identified the colon as the source of the watery diarrhoea and potassium (K+) losses, and symptoms only resolved after colectomy. Immunohistochemistry of the colon revealed over-expression of high conductance K+ (BK) channel protein in surface colonocytes and crypt cells compared with controls and other patients with ESRD. We hypothesize that colonic ischaemia during haemorrhagic shock led to increased BK channel expression and thus enhanced colonic K+ and water secretion, resulting in severe hypokalaemia and colonic pseudo-obstruction. [ABSTRACT FROM AUTHOR]