Zobrazení zdroje stránky Jeffersonalford9936

Iron oxides and dissimilated metal-reducing bacteria (DMRB) have been reported to result in a reduction in methane (CH4) emissions in constructed wetlands (CWs), but their mechanisms on CH4 production and oxidation remains unclear. Here, a set of CW matrix systems (Control, Fe-CWs, and FeB-CWs) was established to analyze the CH4 emission reduction from various angles, including the valencies of iron, microbial community structure and enzyme activity. The results revealed that the addition of iron oxides promoted the electron transfer between methanogens and Geobacter to promote CH4 production, but it was interesting that iron oxides also reduced the enzymes involved in the carbon dioxide (CO2) reduction pathway and promoted the enzymes that participated in anaerobic oxidation of methane (AOM) thereby leading to the overall reduction in CH4 emissions. Moreover, DMRB could promote iron reduction thereby further reducing CH4 emissions by promoting AOM and competing with methanogens for organic substrates.Hybrid osmotic membrane bioreactor (OMBR) takes advantage of the cooperation of varying biological or desalination processes and can achieve NEWS (nutrient-energy-water-solute) recovery from wastewater. However, a lack of universal parameters hinders our understanding. Herein, system configurations and new parameters are systematically investigated to help better evaluate recovery performance. High-quality water can be produced in reverse osmosis/membrane distillation-based OMBRs, but high operation cost limits their application. Although bioelectrochemical system (BES)/electrodialysis-based OMBRs can effectively achieve solute recovery, operation parameters should be optimized. Nutrients can be recovered from various wastewater by porous membrane-based OMBRs, but additional processes increase operation cost. Electricity recovery can be achieved in BES-based OMBRs, but energy balances are negative. Although anaerobic OMBRs are energy-efficient, salinity accumulation limits methane productions. Additional efforts must be made to alleviate membrane fouling, control salinity accumulation, optimize recovery efficiency, and reduce operation cost. This review will accelerate hybrid OMBR development for real-world applications.While cell membrane composition is critical for the function of membrane proteins, membrane modification has not been used to control the rate of extracellular electron transfer (EET) via the outer membrane protein complexes. Here, the rate of electron flow via the cell-surface redox protein, MtrC, was highly enhanced upon change in the outer membrane composition in Shewanella oneidensis MR-1. The MR-1 strain was pre-cultured at 4 °C and 30 °C to initiate differentiation of membrane composition. The whole-cell difference electrochemical assay of wild-type and mutant strains lacking MtrC suggested that the rate of EET via MtrC increased approximately 18 times at 4 °C than 30 °C. Circular dichroism spectroscopy showed that the molar exciton coupling coefficient for inter-heme interaction in MtrC increased in MR-1 at 4 °C than 30 °C. Results suggest that membrane modification may be a novel strategy for improving the efficiency of EET-based technologies.Hydrogen and gaseous fuel derived from wastes have opened up promising alternative pathways for the production of renewable and sustainable fuels to substitute classical fossil energy resources that cause global warming and pollution. Existing review articles focus mostly on gasification, reforming and pyrolysis processes, with limited information on particularly gaseous fuel production via pyrolysis of various waste products. This review provides an overview on the recent advanced pyrolysis technology used in hydrogen and gaseous fuel production. [https://www.selleckchem.com/products/blu-222.html BLU-222 concentration] The key parameters to maximize the production of specific compounds were discussed. More studies are needed to optimize the process parameters and improve the understanding of reaction mechanisms and co-relationship between these advanced techniques. These advanced techniques provide novel environmentally sustainable and commercially procedures for waste-based production of hydrogen and gaseous fuels.Transition metal compounds have been widely used to enhance the anaerobic digestion (AD) performance, while the role of transition metal compounds in enhancing AD performance remains unclarified. In this work, the function of transition metal oxide accelerants (tantalum oxide, niobium oxide, hafnium oxide, and tungsten oxide) in enhanced AD systems was investigated from experimental and theoretical standpoints. Higher biogas production (565.01-617.85 mL/g VS), chemical oxygen demand degradation rate (67.17%-70.45%), total solids and volatile solids reduction rates (29.76%-34.71%, 51.83%-60.88%) were achieved in AD systems with transition metal oxide accelerants than the control (327.08 mL/g VS, 56.65%, 22.65%, and 41.18%). The first-principle density functional theory calculations, electron exchange capacity analysis, and the 16S rRNA gene pyrosequencing demonstrated superior electron transfer and exchange capacities as well as microbial consortia development in transition metal oxides-induced DIET mechanism. This work provides a promising strategy for understanding the function of high-performance accelerants in AD systems.The present study aimed to demonstrate the utilization of unpurified industrial CO2 with low impurities for acetate production via microbial electrosynthesis (MES) for the first time. In MES experiments with CO2-rich brewery gas, the enriched mixed culture dominated by Acetobacterium produced 1.8 ± 0.2 g/L acetic acid at 0.26 ± 0.03 g/Lcatholyte/d rate and outperformed a pure culture of Clostridium ljungdahlii (1.1 ± 0.02 g/L; 0.138 ± 0.004 g/Lcatholyte/d). The electron recovery in acetic acid was also more for mixed culture (84 ± 13%) than C. ljungdahlii (42 ± 14%). Electrochemical analysis of biocathodes suggested the role of microbial biofilm in improved hydrogen electrocatalysis. In comparative gas fermentation tests, the mixed culture outperformed C. ljungdahlii and produced acetic acid at a similar level with both industrial and pure CO2 feedstocks. These results suggest the robustness and capability of the mixed microbial community for utilizing slightly impure industrial CO2 for bioproduction and presents a major advancement in MES technology.