Development, performance and microbial community analysis of a continuous-flow microalgal-bacterial biofilm photoreactor for municipal wastewater treatment.

This work reported the development, performance and microbial community of microalgal-bacterial biofilms cultivated in a continuous-flow photoreactor for municipal wastewater treatment under various conditions. Results showed that microalgal-bacterial biofilms were successfully developed at a HRT of 9 h without external aeration, with a biofilm concentration of around 4690 mg/L being achieved in the steady-state. It was found that further increase of HRT to 12 h did not improve the overall accumulation of biofilm, whereas the growth of microalgae in biofilms was faster than bacteria in the initial stage, indicated by an increased chlorophyll-a&b content in biofilms. After which, the chlorophyll-a&b content in biofilms gradually stabilized at the level comparable with the seed, suggesting that there was a balanced distribution of microalgae and bacteria in biofilms. About 90% of TOC, 71.4% of total nitrogen and 72.6% of phosphorus were removed by microalgal-bacterial biofilms mainly through assimilation in the steady-state photoreactor run at the HRT of 12 h with external aeration. The community analysis further revealed that Cyanobacteria and Chloroflexi were the main components, while Chlorophyta appeared to be the dominant eukaryotic algal community in biofilms. This study could offer new insights into the development of microalgal-bacterial biofilms in a continuous-flow photoreactor for sustainable low-carbon municipal wastewater treatment.

Enhanced antibiotic degradation via photo-assisted peroxymonosulfate over graphitic carbon nitride nanosheets/CuBi2O4: Highly efficiency of oxygen activation and interfacial charge transfer.

Improving the activation capacity of peroxymonosulfate (PMS) to increase radical and non-radical production is critical for antibiotic degradation. However, how to boost reactive oxygen species (ROS) and speed interfacial charge transfer remains an essential challenge. We report a coupling system of 10 %CNNS/CuBi2O4 photocatalyst and sulfate radical-based advanced oxidation processes (SO4--AOPs) to enhance the activation of PMS and improve antibiotic degradation. Owing to highly efficient oxygen activation and interfacial charge transfer, the degradation efficiency of the photo-assisted PMS system was as high as 51.6 times and 2.8 times that of photocatalyst and SO4--AOPs alone, respectively. Importantly, the highly efficient oxygen activation resulted in the production of O2-, which in turn could utilize the excess electrons generated through efficient interfacial charge transfer to convert into non-radical 1O2. The total organic carbon (TOC) elimination effectiveness of the photo-assisted PMS system reached 82 % via the synergy of radicals and non-radicals (O2-, OH, 1O2, SO4-, h+). This system also had excellent potential for reducing the generation and toxicity of disinfection by-products (DBPs), as evidenced through significant reductions in concentrations of trichloromethane (TCM), dichloroacetic acid (DCAA), and trichloronitromethane (TCNM) by 76 %, 64 %, and 35 %, respectively, providing an effective and eco-friendly strategy for antibiotic treatment.

Microalgal capture of carbon dioxide: A carbon sink or source?

The rapidly evolving global warming is triggering all levels of actions to reduce industrial carbon emissions, while capturing carbon dioxide of industrial origin via microalgae has attracted increasing attention. This article attempted to offer preliminary analysis on the carbon capture potential of microalgal cultivation. It was shown that the energy consumption-associated with operation and nutrient input could significantly contribute to indirect carbon emissions, making the microalgal capture of carbon dioxide much less effective. In fact, the current microalgae processes may not be environmentally sustainable and economically viable in the scenario where the carbon footprints of both upstream and downstream processing are considered. To address these challenging issues, renewable energy (e.g., solar energy) and cheap nutrient source (e.g., municipal wastewater) should be explored to cut off the indirect carbon emissions of microalgae cultivation, meanwhile produced microalgae, without further processing, should be ideally used as biofertilizer or aquafeeds for realizing complete nutrients recycling.

Direct ammonium recovery from the permeate of a pilot-scale anaerobic MBR by biochar to advance low-carbon municipal wastewater reclamation and urban agriculture.

The rapidly evolving global climate change has an unprecedented impact sustainable water supply, but also challenges and water shortage global food security. In such a dynamic situation, this study explored direct recovery of ammonium from the effluent of a pilot-scale anaerobic membrane bioreactor (AnMBR) treating actual municipal wastewater via biochar adsorption, while the use of produced ammonium-loaded biochar for urban agriculture was also demonstrated. Results showed that modified biochar could remove almost all ammonium in the pilot AnMBR permeate at an empty bed contact time of 30 mins. Results showed that ammonium extracted from the ammonium-loaded biochar could promote the germination of Daikon radish seeds. It was further observed that the fresh weight of Pak Choi (a typical leafy vegetable) planted in the soils augmented with the ammonium-loaded biochar was 42.5 g per vegetable versus 18.5 g per vegetable in the control, indicating a 130 % of increase in the Pak Choi productivity. In addition, the Pak Choi in grown the ammonium-loaded biochar augmented soils appeared to be much bigger with larger leaves compared to the control. It was also worth to note that the ammonium-loaded biochar could significantly stimulate the root development of Pak Choi, i.e., 20.7 cm over 10.5 cm obtained in the control. More importantly, the amount of carbon emission reduced through returning ammonium-loaded biochar to urban agriculture could offset the treatment process-associated direct and indirect carbon emission.

Key immunity characteristics of diverse stages of brucellosis in rural population from Inner Mongolia, China.

BACKGROUND: Brucellosis poses a serious threat to human and animal health, particularly in developing countries such as China. The Inner Mongolia Autonomous Region is one of the most severely brucellosis-endemic provinces in China. Currently, the host immune responses functioning to control Brucella infection and development remain poorly understood. The aim of this study is to further clarify the key immunity characteristics of diverse stages of brucellosis in Inner Mongolia. METHODS: We collected a total of 733 blood samples from acute (n = 137), chronic (n = 316), inapparent (n = 35), recovery (n = 99), and healthy (n = 146) groups from the rural community of Inner Mongolia between 2014 and 2015. The proportions of CD4+, CD8+, Th1, Th2, and Th17 T cells in peripheral blood and the expression of TLR2 and TLR4 in lymphocytes, monocytes and granulocytes were examined using flow cytometry analysis. The differences among the five groups were compared using one-way ANOVA and the Kruskal-Wallis method, respectively. RESULTS: Our results revealed that the proportions of CD4+ and CD8+ T cells were significantly different among the acute, chronic, recovery, and healthy control groups (P < 0.05), with lower proportions of CD4+ T cells and a higher proportion of CD8+ T cells in the acute, chronic, and recovery groups. The proportion of Th1 cells in the acute, chronic, and inapparent groups was higher than that in the healthy and recovery groups; however, there was no significant difference between patients and healthy individuals (P > 0.05). The proportion of Th2 lymphocytes was significantly higher in the acute and healthy groups than in the inapparent group (P < 0.05). The proportion of Th17 cells in the acute group was significantly higher than that in the healthy control, chronic, and inapparent groups (P < 0.05). Finally, the highest expression of TLR4 in lymphocytes, monocytes and granulocytes was observed in the recovery group, and this was followed by the acute, chronic, healthy control, and inapparent groups. There was a significant difference between the recovery group and the other groups, except for the acute group (P < 0.05). Moreover, a correlation in TLR4 expression was observed in lymphocytes, monocytes and granulocytes among the five groups (r > 0.5), except for the inapparent group between lymphocytes and granulocytes (r = 0.34). CONCLUSIONS: Two key factors (CD8+ T cells and TLR4) in human immune profiles may closely correlate with the progression of brucellosis. The detailed function of TLR4 in the context of a greater number of cell types or tissues in human or animal brucellosis and in larger samples should be further explored in the future.

The rational design of specific SOD1 inhibitors via copper coordination and their application in ROS signaling research.

Efficient methods for the regulation of intracellular O2˙- and H2O2 levels, without altering intracellular processes, are urgently required for the rapidly growing interest in ROS signaling, as ROS signaling has been confirmed to be involved in a series of basic cellular processes including proliferation, differentiation, growth and migration. Intracellular H2O2 is formed mainly via the catalytic dismutation of O2˙- by SODs including SOD1, SOD2 and SOD3. Thus, the intracellular levels of O2˙- and H2O2 can directly be controlled through regulating SOD1 activity. Here, based on the active site structure and catalytic mechanism of SOD1, we developed a new type of efficient and specific SOD1 inhibitors which can directly change the intracellular levels of H2O2 and O2˙-. These inhibitors inactivate intracellular SOD1 via localization into the SOD1 active site, thereby coordinating to the Cu2+ in the active site of SOD1, blocking the access of O2˙- to Cu2+, and breaking the Cu2+/Cu+ catalytic cycle essential for O2˙- dismutation. The reduced ERK1/2 phosphorylation induced by the specific SOD1 inactivation-mediated decrease of intracellular H2O2 levels reveals the potential of these specific SOD1 inhibitors in understanding and regulating ROS signaling. Furthermore, these specific SOD1 inhibitors also lead to selectively elevated cancer cell apoptosis, indicating that these kinds of SOD1 inhibitors might be candidates for lead compounds for cancer treatment.