Optimizing the algae-bacteria biofilm reactor for imidacloprid wastewater treatment: An evaluation of hydraulic retention times for enhanced efficiency and energy savings.

Recent observations have highlighted the rapidly growing prevalence of emerging contaminants such as Imidacloprid (IMI) within our environment. These insecticidal pollutants, coexisting with more traditional contaminants, have become predominant in aquatic systems, posing risks to both human and ecological well-being. Among the various wastewater treatment approaches tested, biofilm reactors are currently gaining prominence. In this study, we employed an Algae-Bacteria Biofilm Reactor (ABBR) to concurrently address both conventional and emergent contaminants, specifically IMI, over an extended timeframe. Following a 60-day assessment, the ABBR consistently demonstrated removal efficiencies exceeding 85% for total dissolved nitrogen, ammonia nitrogen, and total dissolved phosphorus, and also achieved removal efficacy for the soluble chemical oxygen demand (sCOD). Despite the removal efficiency of IMI (with initial concentration is 1.0 mg/L) in ABBR showed a gradual decline over the extended period, it remained consistently effective over 50% due to the microalgae-mediated free radical reactions, indicating the ABBR's sustained efficiency in long-duration operations. Additionally, applying some non-conventional modifications, like aeration removal and reducing light exposure, demonstrated minimal impact on the reactor's pollutant removal efficiencies, achieving comparable results to the control group (which utilized aeration with a 14:10 light/dark ratio), 0.92 kW h/L/d of electricity can be saved economically, which accentuated the potential for energy conservation. An in-depth analysis of the treated effluents from the ABBRs, using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technique, uncovered four potential transformation pathways for IMI. Overall, our findings suggest that these optimized processes did not influence the transformation products of IMI, thereby reaffirming the viability of our proposed optimization.

CircRSU1 alleviates LPS-induced human pulmonary microvascular endothelial cell injury by targeting miR-1224-5p/ITGA5 axis.

To investigate the potential functions and regulatory mechanism of circRSU1 on septic acute lung injury (sepsis-ALI) progression. We used lipopolysaccharide (LPS)-stimulated human pulmonary microvascular endothelial cells (HPMECs) to establish the cell model of sepsis-ALI in vitro. qRT-PCR and Western blotting were used for the detection of genes and proteins. The migration and tubulogenesis of HPMECs were assessed by transwell, wound healing, and tube formation assays. Inflammatory factors were detected by ELISA analysis. Cell permeability (PA) was determined by transendothelial resistance (TEER) and fluorescein isothiocyanate (FITC) with transwell assay. The interaction between miR-1224-5p and circRSU1 or ITGA5 (Integrin Subunit Alpha 5) was studied by dual-luciferase reporter and RNA pull-down assays. CircRSU1 expression was decreased after LPS treatment in HPMECs. Functionally, re-expression of circRSU1 in HPMECs could alleviate LPS-induced inflammatory response, the inhibition of cell migration and tube formation and enhancement of cell permeability. Mechanistically, circRSU1 acted as a sponge for miR-1224-5p. LPS treatment enhanced miR-1224-5p expression, and inhibition of miR-1224-5p reversed LPS-evoked HPMEC dysfunction mentioned above. Moreover, miR-1224-5p could abolish the protective effects of circRSU1 on HPMECs. In addition, miR-1224-5p directly targeted ITGA5, and circRSU1 was able to regulate ITGA5 expression via interacting with miR-1224-5p. CircRSU1 could alleviate LPS-induced HPMEC injury by miR-1224-5p/ITGA5 axis, indicating the potential molecular contribution of circRSU1 in sepsis-ALI.

Changes of bacterial community structure,monosaccharide composition and CO2 exchange along the successional stages of biological soil crusts.

Biological soil crusts (BSCs) are a dominant ecological landscape of drylands, which have a significant impact on global biogeochemical flux. However, it is unclear how bacterial community and physiological characteristics vary along the BSCs successional stages. In this study, bacterial community composition, physiological characteristics, and monosaccharide composition of extracellular polysaccharides (EPSs) were compared among different successional stages. Our findings demonstrated that besides the dominant bacterial species, the bacterial communities also showed considerable differences between these two stages. Cyanobacteria were keystone taxa in the early stage, while heterotrophic bacteria (Proteobacteria, Actinobacteria and Acidobacteria) were keystone taxa in the later stages. According to the results of CO2 exchange, cyanobacterial crusts accumulated net carbon faster than moss crusts, while moss crusts had a significantly higher respiration rate. The monosaccharide analysis indicated that the EPSs components also varied depending on BSCs' successional stages. Specifically, the contents of rhamnose and arabinose were higher in the cyanobacterial crusts than other types of crusts, while the contents of fucose, xylose, mannose and glucose were the highest in cyanobacterial-lichen crusts, and galactose content was highest in the moss crusts. Altogether, our results stress the heterogeneous variation of BSCs along with succession, and this work offered a fresh viewpoint for a deeper comprehension of the interactions between the monosaccharide components of EPS and the networks of bacterial communities in BSCs.

Performance of a biocrust cyanobacteria-indigenous bacteria (BCIB) co-culture system for nutrient capture and transfer in municipal wastewater.

This study aimed to explore the potential for transferring nutrients from municipal wastewater through the cultivation of biocrust cyanobacteria, since little is known regarding the growth and bioremediation performance of biocrust cyanobacteria in actual wastewater, especially their interaction with indigenous bacteria. Therefore, in this study, the biocrust cyanobacterium, Scytonema hyalinum was cultivated in municipal wastewater under different light intensities, to establish a biocrust cyanobacteria-indigenous bacteria (BCIB) co-culture system, in order to investigate its nutrient removal efficiency. Our results revealed that the cyanobacteria-bacteria consortium could remove up to 91.37 % and 98.86 % of dissolved nitrogen and phosphorus from the wastewater, respectively. The highest biomass accumulation (max. 6.31 mg chlorophyll-a L-1) and exopolysaccharide secretion (max. 21.90 mg L-1) were achieved under respective optimized light intensity (60 and 80 µmol m-2 s-1). High light intensity was found to increase exopolysaccharide secretion, but negatively impacted cyanobacterial growth and nutrient removal. Overall, in the established cultivation system, cyanobacteria accounted for 26-47 % of the total bacterial abundance, while proteobacteria consisted up to 50 % of the mixture. The composition and ratio of cyanobacteria to indigenous bacteria were shown to be altered by adjusting the light intensity of the system. Altogether, our results clearly illustrate the potential of the biocrust cyanobacterium S. hyalinum in establishing a BCIB cultivation system under different light intensity for wastewater treatment and other end-applications (e.g., biomass accumulation and exopolysaccharide secretion). This study presents an innovative strategy for transferring nutrients from wastewater to drylands through cyanobacterial cultivation and subsequent biocrust induction.

Efficient removal of thiamethoxam by freshwater microalgae Scenedesmus sp. TXH: Removal mechanism, metabolic degradation and application.

Neonicotinoids, as the most widely used pesticides in the world, help improve the production of crops. Meanwhile, it also brings potential threats to surrounding environments and other organisms because of its wide use and even abuse. In this study, Scenedesmus sp. TXH isolated from a wastewater treatment plant was used to remove the neonicotinoid pesticide thiamethoxam (THIA). The removal efficiency, degradation pathway, metabolite fate of THIA and physicochemical effects on microalgae cells were studied. Meanwhile, the feasibility of using microalgal technology to remove THIA from municipal wastewater was also explored. The results showed that 5-40 mg/L of THIA slightly promoted the growth of microalgae, while 60 mg/L THIA severely inhibited microalgal growth. It was observed that malondialdehyde content and superoxide dismutase activity in 60 mg/L THIA group increased significantly (p < 0.05) in the early stage of the experiment, indicating that THIA caused oxidative damage to microalgae. Scenedesmus sp. TXH showed high-efficient degradation ability and high resistance to THIA, with 100% removal of THIA at 5, 20 and 40 mg/L groups and 97.5% removal of THIA at 60 mg/L group on day 12. THIA was mainly removed by biodegradation, accounting for 78.18%, 93.50%, 96.81% and 91.35% under 5, 20, 40 and 60 mg/L on day 12, respectively. Six degradation products were identified, and four potential degradation pathways were proposed. In practical wastewater, the removal efficiency of total dissolved nitrogen, total dissolved phosphorus, ammonia nitrogen and THIA reached 85.68%, 90.00%, 98.43% and 100%, respectively, indicating that Scenedesmus sp. TXH was well adapted to the wastewater and effectively removed THIA and conventional pollutants.

[Seasonal dynamics of the physicochemical properties of biological crusts exopolysaccharides and the microbial community structure]. / 生物结皮胞外多糖理化特性及菌群结构的季节动态.

Exopolysaccharides (EPS), an important substance of cyanobacteria in resisting stresses, are the main form of carbon storage in biocrusts and play an important role in material cycling and stability of biocrusts. In this study, the biocrusts in different seasons (January, April, July, October) were collected from Gurbantunggut Desert, and the dynamics of EPS content, composition, morphological characteristics and microbial community structures were analyzed. The results showed that: 1) The excretion of EPS showed obvious seasonal dynamics. The EPS contents in January, April, July and October were 81.72, 52.46, 76.77, 70.54 µg·cm-2, and the chlorophyll a contents were 2.7, 4.94, 4.2 and 5.98 µg·cm-2, respectively. Cyanobacteria allocated more fixed organic carbon to EPS in winter and summer, and more to their own biomass accumulation in spring and autumn. 2) EPS in biocrusts of each season was composed of seven kinds of monosaccharides. The sum of relative mole percentages of glucose and galactose was 46%-56%, much higher than the other five monosaccharides. The monosaccharide compositions of EPS were significantly affected by temperature and precipitation. There was no significant difference in the Fourier infrared spectra of EPS in biocrusts across different seasons. 3) The observation results of atomic force microscope showed that more filamentous and thick rope-like structures occurred in EPS in July and October, while the EPS showed block-like morphology in January and April. 4) The results of 16S rDNA high-throughput sequencing showed that Cyanobacteria and Microcoleus were the dominant bacterial phyla and genus in biocrusts in all the four seasons, with significantly higher relative abundance than other bacterial phyla and genera. The relative abundance of Proteobacteria was significantly positively correlated with the relative mole percentages of fucose and galactose, indicating that the composition of monosaccharides affected heterotrophic bacteria in crusts. In deserts, environmental factors such as temperature and moisture changed significantly across seasons. The physicochemical properties of biocrust exopolysaccharides and the seasonal dynamics of bacterial communities were controlled by multiple factors, such as temperature, moisture, and light.

Efficient removal of Imidacloprid and nutrients by algae-bacteria biofilm reactor (ABBR) in municipal wastewater: Performance, mechanisms and the importance of illumination.

Neonicotinoids, such as Imidacloprid (IMI), are frequently detected in water and wastewater, posing a threat on both the environment and the health of living things. In this work, a novel algae-bacteria biofilm reactor (ABBR) was constructed to remove IMI and conventional nutrients from municipal wastewater, aiming to explore the removal effect and advantage of ABBR. Results showed that ABBR achieved 74.9% removal of IMI under 80 µmol m-2·s-1 light, higher than photobioreactor (PBR) without biofilm (61.2%) or ABBR under 40 µmol m-2·s-1 light (48.4%) after 16 days of operation. Moreover, it also showed that ABBR allowed a marked improvement on the removal of total dissolved nitrogen (TDN), total dissolved phosphorus (TDP) and soluble chemical oxygen demand (sCOD). ABBR showed different IMI removal efficiencies and bacterial communities under different light conditions, indicating that light played an important role in driving ABBR. The merits of ABBR are including (i) ABBR showed rapid pollutant removal in a short time, (ii) in ABBR, stable consortiums were formed and chlorophyll content in effluent was very low, (iii) compared with PBR, degradation products in ABBR showed lower biological toxicity. Our study highlights the benefits of ABBR on IMI removing from municipal wastewater and provides an effective and environment-friendly engineering application potential of IMI removal.

Intelligent Rapid Adaptive Offloading Algorithm for Computational Services in Dynamic Internet of Things System.

As restricted resources have seriously limited the computational performance of massive Internet of things (IoT) devices, better processing capability is urgently required. As an innovative technology, multi-access edge computing can provide cloudlet capabilities by offloading computation-intensive services from devices to a nearby edge server. This paper proposes an intelligent rapid adaptive offloading (IRAO) algorithm for a dynamic IoT system to increase overall computational performance and simultaneously keep the fairness of multiple participants, which can achieve agile centralized control and solve the joint optimization problems related to offloading policy and resource allocation. For reducing algorithm execution time, we apply machine learning methods and construct an adaptive learning-based framework consisting of offloading decision-making, radio resource slicing and algorithm parameters updating. In particular, the offloading policy can be rapidly derived from an estimation algorithm based on a deep neural network, which uses an experience replay training method to improve model accuracy and adopts an asynchronous sampling trick to enhance training convergence performance. Extensive simulations with different parameters are conducted to maintain the trade-off between accuracy and efficiency of the IRAO algorithm. Compared with other candidates, the results illustrate that the IRAO algorithm can achieve superior performance in terms of scalability, effectiveness and efficiency.