Electrochemical technologies for water treatment, resource recovery, energy generation, and energy storage rely on charged polymer membranes to selectively transport ions. With the rise of applications involving hypersaline brines, such as management of desalination brine or the recovery of ions from brines, there is an urgent need for membranes that can sustain high conductivity and selectivity under such challenging conditions. Current membranes are constrained by an inherent trade-off between conductivity and selectivity, alongside concerns regarding their high costs. Moreover, a gap in the fundamental understanding of ion transport within charged membranes at high salinities prevents the development of membranes that could meet these stringent requirements efficiently. Here, we present the synthesis of scalable, highly charged membranes that demonstrate high conductivity and selectivity while contacting 1 and 5 molal NaCl solutions. A detailed analysis of the membrane transport properties reveals that the high proportion of bound water in the membranes, enabled by the high charge content and hydrophilic structure of the polymers, enhances both the ion partitioning and diffusion selectivities of the membranes. These structure/property relationships derived from this study offer valuable guidance for designing next-generation membranes that simultaneously achieve exceptional conductivity and selectivity in high-salinity conditions.

Steroid hormones exhibit potent endocrine disrupting activity and have been shown to disrupt the equilibrium of aquatic ecosystems and pose a threat to public health through their persistent and carcinogenic effects. Pontibacillus chungwhensis HN14, a moderately halophilic bacterium with the capacity to effectively degrade various polycyclic aromatic hydrocarbons and other organic pollutants, was previously isolated. Additionally, the strain HN14 showed strong environmental adaptability under various environmental stress conditions. In this study, the steroid degradation by strain HN14 was studied for the first time. We demonstrated that strain HN14 could degrade estradiol (E2) to maintain the growth of the strain and could convert E2 to estrone. Additionally, the efficient substrate degradation efficiency of P. chungwhensis HN14 under high salinity and high substrate concentration conditions was demonstrated. Furthermore, a 17β-hydroxysteroid dehydrogenase, 17β-HSD(HN14), was identified in strain HN14. Comparative analysis reveals that 17β-HSD(HN14) shares approximately 38% sequence identity with 17β-HSDx from Rhodococcus sp. P14. In addition, 100 µg of purified 17β-HSD(HN14) could effectively convert about 40% of 0.25 mM of E2 within 1 h period, with an enzyme activity of 17.5 U/mg, and catalyze the dehydrogenation of E2 and testosterone at the C-17 position. The characterization of purified enzyme properties reveals that 17β-HSD(HN14) exhibits exceptional structural robustness and enzymatic efficacy even under high salinity conditions of up to 20%. Overall, this study enhances our comprehension of steroid biodegradation in strain HN14 and contributes novel ideas and theoretical underpinnings for advancing bioremediation technologies targeting steroid pollution in high-saline environments.

Anaerobic Membrane Bioreactor (AnMBR) are employed for solid-liquid separation in wastewater treatment, enhancing process efficiency of digestion systems treating digestate. However, membrane fouling remains a primary challenge. This study operated a pilot-scale AnMBR (P-AnMBR) to treat high-concentration organic digestate, investigating system performance and fouling mechanisms. P-AnMBR operation reduced acid-producing bacteria and increased methane-producing bacteria on the membrane, preventing acid accumulation and ensuring stable operation. The P-AnMBR effectively removed COD and VFA, achieving removal rates of 82.3 % and 92.0 %, respectively. Higher retention of organic nitrogen and lower retention of ammonia nitrogen were observed. The membrane fouling consisted of organic substances (20.3 %), predominantly polysaccharides, and inorganic substances (79.7 %), primarily Mg ions (10.1 %) and Ca ions (4.5 %). To reduce the increased transmembrane pressure (TMP) caused by fouling (a 10.6-fold increase in filtration resistance), backwash frequency experiment was conducted. It revealed a 30-min backwash frequency minimized membrane flux decline, facilitating recovery to higher flux levels. The water produced amounted to 70.3 m³ over 52 days. The research provided theoretical guidance and practical support for engineering applications, offering practical insights for scaling up P-AnMBR.

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We conducted transcriptome sequencing on salt-tolerant mutants X5 and X3, and a control (Ctr) strain of Gracilariopsis lemaneiformis after treatment with artificial seawater at varying salinities (30‱, 45‱, and 60‱) for 3 weeks. Differentially expressed genes were identified and a weighted co-expression network analysis was conducted. The blue, red, and tan modules were most closely associated with salinity, while the black, cyan, light cyan, and yellow modules showed a close correlation with strain attributes. KEGG enrichment of genes from the aforementioned modules revealed that the key enrichment pathways for salinity attributes included the proteasome and carbon fixation in photosynthesis, whereas the key pathways for strain attributes consisted of lipid metabolism, oxidative phosphorylation, soluble N-ethylmaleimide-sensitive factor-activating protein receptor (SNARE) interactions in vesicular transport, and porphyrin and chlorophyll metabolism. Gene expression for the proteasome and carbon fixation in photosynthesis was higher in all strains at 60‱. In addition, gene expression in the proteasome pathway was higher in the X5-60 than Ctr-60 and X3-60. Based on the above data and relevant literature, we speculated that mutant X5 likely copes with high salt stress by upregulating genes related to lysosome and carbon fixation in photosynthesis. The proteasome may be reset to adjust the organism\'s proteome composition to adapt to high-salt environments, while carbon fixation may aid in maintaining material and energy metabolism for normal life activities by enhancing carbon dioxide uptake via photosynthesis. The differences between the X5-30 and Ctr-30 expression of genes involved in the synthesis of secondary metabolites, oxidative phosphorylation, and SNARE interactions in vesicular transport suggested that the X5-30 may differ from Ctr-30 in lipid metabolism, energy metabolism, and vesicular transport. Finally, among the key pathways with good correlation with salinity and strain traits, the key genes with significant correlation with salinity and strain traits were identified by correlation analysis.

High salinity inhibits microbial activity in the bioremediation of saline wastewater. To alleviate osmotic stress, glycine betaine (GB), an osmoprotectant, is added to enhance the secretion of extracellular polymeric substances (EPS). These EPS are pivotal in withstanding environmental stressors, yet the intricate interplay between GB supplementation and microbial responses through EPS modifications-encompassing composition, molecular architecture, and electrochemical features-remains elusive in hypersaline conditions. Here we show microbial strategies for salinity endurance by investigating the impact of GB on the dynamic alterations of EPS properties. Our findings reveal that GB supplementation at 3.5% salinity elevates the total EPS (T-EPS) content from 12.50 ± 0.05 to 24.58 ± 0.96 mg per g dry cell weight. The observed shift in zeta potential from -28.95 to -6.25 mV at 0% and 3.5% salinity, respectively, with GB treatment, indicates a reduction in electrostatic repulsion and compaction. Notably, the EPS protein secondary structure transition from β-sheet to α-helix, with GB addition, signifies a more compact protein configuration, less susceptible to salinity fluctuations. Electrochemical analyses, including cyclic voltammetry (CV) and differential pulse voltammetry (DPV), reveal GB\'s role in promoting the release of exogenous electron shuttles, such as flavins and c-type cytochromes (c-Cyts). The enhancement in DPV peak areas (QDPV) with GB addition implies an increase in available extracellular electron transfer sites. This investigation advances our comprehension of microbial adaptation mechanisms to salinity through EPS modifications facilitated by GB in saline habitats.

Jasmonate (JA) is a well-known phytohormone essential for plant response to biotic stress. Recently, a crucial role of JA signaling in salt resistance has been highlighted; however, the specific regulatory mechanism remains largely unknown. In this study, we found that the NUCLEAR FACTOR-Y (NF-Y) subunits NF-YA1, NF-YB2, and NF-YC9 form a trimeric complex that positively regulates the expression of salinity-responsive genes, whereas JASMONATE-ZIM DOMAIN protein 8 (JAZ8) directly interacts with three subunits and acts as the key repressor to suppress both the assembly of the NF-YA1-YB2-YC9 trimeric complex and the transcriptional activation activity of the complex. When plants encounter high salinity, JA levels are elevated and perceived by the CORONATINE INSENSITIVE (COI) 1 receptor, leading to the degradation of JAZ8 via the 26S proteasome pathway, thereby releasing the activity of the NF-YA1-YB2-YC9 complex, initiating the activation of salinity-responsive genes, such as MYB75, and thus enhancing the salinity tolerance of plants.

The N-acyl-homoserine lactones (AHLs)-mediated quorum-sensing (QS) system played a crucial role in regulating biological nitrogen removal and biofilm formation. However, the regulatory role of AHLs on nitrogen removal bacteria in high salinity environment has remained unclear. This study evaluated the roles and release patterns of AHLs in Vibrio sp. LV-Q1 under high salinity condition. Results showed that Vibrio sp. primarily secretes five AHLs, and the AHLs activity is strongly correlated with the bacterial density. Exogenous C10-HSL and 3OC10-HSL were found to significantly enhance ammonium removal, while making a minor contribution to the growth rate. Both the C10-HSL and 3OC10-HSL promoted the biofilm formation of Vibrio sp. with an enhancement of 1.64 and 1.78 times, respectively. The scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM) observations confirmed the biofilm-enhancing effect of AHLs. Further analysis revealed that AHLs significantly improved bacterial self-aggregation and motility, as well as the level of extracellular polymeric substances (EPS). These findings provide significant guidance on construction of nitrification system at high salinity.

Salinity, a critical factor, could directly or indirectly affect the microbial community structure and diversity. Changes in salinity levels act as environmental filters that influence the transformation of key microbial species. This study investigates the adaptive characteristics of indigenous microflora in groundwater in relation to external organic pollutants under high salinity stress. A highly mineralized shallow groundwater in Northwest China was conducted as the study area, and six representative sampling points were chosen to explore the response of groundwater hydrochemical parameters and microflora, as well as to identify the tolerance mechanisms of indigenous microflora to combined pollution. The results revealed that the dominant genera found in high salinity groundwater contaminated with organic pollutants possess the remarkable ability to degrade such pollutants even under challenging high salinity conditions, including Halomonas, Pseudomonas, Halothiobacillus, Sphingomonas, Lutibacter, Aquabacterium, Thiomicrospira, Aequorivita, etc. The hydrochemical factors, including total dissolved solids (TDS), sulfide, nitrite, nitrate, oxidation reduction potential (ORP), NH3-N, Na, Fe, benzene series, phenols, and halogenated hydrocarbons, demonstrated a significant influence on microflora. High levels of sulphate and sulfide in groundwater can exhibit dual effects on microflora. On one hand, these compounds can inhibit the growth and metabolism of microorganisms. On the other hand, they can also serve as effective electron donors/receptors during the microbial degradation of organic pollutants. Microorganisms exhibit resilience to the inhibitory effects of high salinity and organic pollutants via a series of tolerance mechanisms, such as strengthening the extracellular membrane barrier, enhancing the synthesis of relevant enzymes, initiating novel biochemical reactions, improving cellular self-healing capabilities, responding to unfavorable environmental conditions by migration, and enhancing the S cycle for the microbial metabolism of organic pollutants.