CISD2 regulates oxidative stress and mitophagy to maintain the balance of the follicular microenvironment in PCOS.

OBJECTIVES: To observe the CISD2 expression among PCOS patients and to explore its profound impact on the follicular microenvironment. Moreover, we want to elucidate the intricate mechanistic contribution of CISD2 to the onset and progression of PCOS. METHODS: Oxidase NOX2, mitophagy-related proteins, and CISD2 were detected by WB. The changes in mitochondrial structure and quantity were observed by transmission electron microscopy. Mitochondrial and lysosome colocalization was used to detect the changes of mitophagy. MDA kit, GSH and GSSG Assay kit and ROS probe were used to detect oxidative stress damage. RESULTS: We found that CISD2, mitophagy and oxidase in the GCs of PCOS patients were significantly increased. Testosterone stimulation leads to the increase of oxidase, mitophagy, and CISD2 in KGN cells. CISD2 inhibition promoted the increase of mitophagy, and the activation of mitochondria-lysosome binding, while alleviating the oxidative stress. CONCLUSIONS: Inhibition of CISD2 can improve the occurrence of oxidative stress by increasing the level of mitophagy, thus affecting the occurrence and development of PCOS diseases.

Effects of polyvinyl chloride microplastics and benzylalkyldimethylethyl compounds on system performance, microbial community and resistance genes in sulfur autotrophic denitrification system.

Benzylalkyldimethylethyl ammonium compounds (BAC) and polyvinyl chloride microplastics (PVC MPs), as the frequently detected pollutants in wastewater treatment plants (WWTPs), have attracted more concerns on their ecosystem risks. Therefore, this study investigated how the sulfur autotrophic denitrification (SAD) system responded to the single and joint stress of PVC MPs (1, 10 and 100 mg/L) and BAC (0.5, 5 and 10 mg/L). After 100 days of operation, the presence of 10 mg/L BAC led to obviously inhibitory effects on system performance and microbial metabolic activity. And the additions of PVC MPs or/and BAC stimulated the proliferation of intracellular resistance genes (RGs), whereas exposure to BAC increased the abundances of extracellular RGs and free RGs in water more significantly. Compared to the joint stress, BAC single stress resulted in higher abundances of free RGs in water, which further increased the risk of RGs propagation. Moreover, the interaction between mobile genetic elements and extracellular polymeric substances further increased the spread of RGs. Pathogens might be the potential hosts of RGs and enriched in SAD system and plastisphere, thereby leading to more serious ecological risks. This study will broaden the understanding of the environmental hazards posed by PVC MPs and BAC in WWTPs.

A bifunctional MoS2/SGCN nanocatalyst for the electrochemical detection and degradation of hazardous 4-nitrophenol.

Herein, we reported the dual functions of molybdenum disulfide/sulfur-doped graphitic carbon nitride (MoS2/SGCN) composite as a sensing material for electrochemical detection of 4-NP and a catalyst for 4-NP degradation. The MoS2 nanosheet, sulfur-doped graphitic carbon nitride (SGCN) and MoS2/SGCN were characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) spectroscopy and X-ray photoelectron spectroscopy (XPS). Electrochemical characterization of these materials with electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) in 1 mM K4[Fe(CN)6]3-/4- show that the composite has the lowest charge transfer resistance and the best electrocatalytic activity. The limit of detection (LOD) and the linear range of 4-nitrophenol at MoS2/SGCN modified glassy carbon electrode (MoS2/SGCN/GCE) were computed as 12.8 nM and 0.1 - 2.6 µM, respectively. Also, the percentage recoveries of 4-NP in spiked tap water samples ranged from 97.8 - 99.1 %. The electroanalysis of 4-NP in the presence of notable interferons shows that the proposed electrochemical sensor features outstanding selectivity toward 4-NP. Additionally, the results of the catalytic degradation of 4-NP at MoS2/SGCN show that the nanocatalyst catalyzed the transformation of 4-NP to 4-aminophenol (4-AP) with a first-order rate constant (k) estimated to be 4.2 ×10-2 s-1. The results of this study confirm that the MoS2/SGCN nanocatalyst is a useful implement for electroanalytical monitoring and catalytic degradation of the hazardous 4-NP in water samples.

Enhanced Thermoelectric Performance in Flexible Sulfur-Alloyed Ag2Se Thin Films.

Flexible thermoelectric generators can directly convert thermal energy harvested from the human body into electricity. The Ag2Se flexible film, a promising material for wearable thermoelectric generators, normally demonstrates an inferior electrical transport property due to its weakened in-plane mobility. In this study, the in-plane electrical transport properties of flexible Ag2Se films were optimized by alloying with additional sulfur. This optimization is achieved by leveraging the differences in elemental electronegativity and the preferred orientation of the Ag2Se films. The sulfur-alloyed Ag2Se thin film, with a nominal ratio of 3 atom %, can reach a maximum mobility of 1150 cm-2 V-1 s-1 at 300 K. So, the optimized room-temperature power factor increases to 1935 µW m-1 K-2. Furthermore, the Ag2Se film alloyed with 3 atom % sulfur exhibits excellent flexibility even after 1000 bending cycles with a radius of 5 mm, characterized by a relative resistance increment of less than 3%. In addition, the corresponding π-type flexible thermoelectric generator possesses a maximum power density of 51 W m-2 at a temperature difference of 50 K.

Solvent-Assisted Structural Modifications of Sulfur Dots Followed by Time-Dependent Emergence of a New Emissive State and Long-Lived Afterglow.

Sulfur dots are a new class of recently developed nonmetallic luminescent nanomaterials with various potential applications. Herein, we synthesized sulfur dots using a mild chemical etching method and then modified the structural features of the as-synthesized sulfur dots using a slow and defined solvent-assisted aggregation process. This increases the particle size and overall crystallinity along with the modifications of the surface functional groups, which eventually show a new emission band at longer wavelengths. Detailed photophysical and temperature-dependent luminescence studies confirmed that the new emissive state evolves due to interparticle interactions in the excited state. Furthermore, the occurrence of a new emissive state in a longer-wavelength region helped reduce the energy gap between the lowest excited singlet state and the lowest excited triplet state in modified sulfur dots, resulting in an aqueous stable room-temperature phosphorescence/afterglow emission through efficient intersystem crossing. This typical efficacious afterglow emission directly shows the potential applicability of structurally modified sulfur dots in encryption devices and can also be potentially effective in light emitting diodes (LED) and sensing devices.

Genesis of the hydrothermal gold system in the kibaran metallogenic province (D.R.Congo): A review for the Twangiza-Namoya gold belt.

The Twangiza-Namoya Gold Deposit within the Kibaran Belt of the Democratic Republic of the Congo represents a crucial manifestation of the hydrothermal gold system. This review investigates its intricate origin and the subsequent metallogenic evolution that has shaped its present-day characteristics and offers a systematic categorization based on its deposition processes and geotectonic settings. The findings reveal that the gold deposits are predominantly derived from sedimentary fluid sources. Within this vast metallogenic province, two stages of gold deposition have been constrained: (a) the early-stage formation related to the accretion of Rodinia assembly with subduction-collisional event where diagenesis cemented the syngenetic pyrite carbonaceous sediments and (b) the later stage deposition related to the continent-collisional event during the last stage of Rodinia supercontinent amalgamation. Previous isotopic investigations, with a particular emphasis on pyrite sulfur isotopes on both host rocks and vein-bearing sulfides, have been instrumental in tracing the origins of gold-bearing fluids in the study region. The isotopic variance in the four deposits: Twangiza (-5.2 % to +3 %, avg. -0.3 %), Kamituga (-0.6 % to -0.9.1 %, avg. -5%), Lugushwa (+3.0 % to -18.4 %), and Namoya, on the southernmost end, has a vast range but with much heavier isotope compositions, ranging between +1.3 % and to +22.6 %, with an average of +12.2 %. The data predominantly points to the sedimentary origins of ore fluids in the Twangiza-Namoya Gold belt, highlighting the pivotal role of sedimentary processes in shaping the metallogenic landscape of the region. The fluids inclusions depicted the deposits to be formed from H2O-Nacl-H2O with abundant CH4 and N2 ore-forming fluid, moderate temperature (350-500 °C), and low salinity. The overall results confirm the genetic style of the Twangiza-Namoya Gold Belt to be an orogenic gold-style deposit that was emplaced during the early Neoproterozoic era in low greenschist facies terrain.

Polyacrylonitrile Based Triblock Copolymer Binder Enabling Excellent Performance toward LiNi0.5Mn1.5O4 and Sulfur Based Batteries.

There is an urgent need for lithium-ion batteries with high energy density to meet the increasing demand for advanced devices and ecofriendly electric vehicles. Spinel LiNi0.5Mn1.5O4 (LNMO) is the most promising cathode material for achieving high energy density due to its high operating voltage (4.75 V vs Li/Li+) and impressive capacity of 147 mAh g-1. However, the binders conventionally used are prone to high potential and oxidation at the cathode side, resulting in a loss of the ability to bond active material and conductive agent integrity. This can lead to severe capacity fading and irreversible battery failure. This study demonstrates that incorporating acrylic anhydride and methyl methacrylate into conventional acrylonitrile through solution polymerization improves the binding energy and voltage resistance. The results indicate that the triblock poly(acrylonitrile-methyl methacrylate-acrylic anhydride) (PAMA) binder has a much higher peeling strength (0.506 N cm-1) compared to its polyvinylidene fluoride (PVDF) counterpart (0.3 N cm-1), making it a more feasible strategy. When assembled with LiNi0.5Mn1.5O4, the PAMA based electrode maintains a capacity retention of 70.7% after 800 cycles at 0.1 C, which is significantly higher than the 33.9% retention of the PVDFbased electrode. This is due to the large number of polar groups, including ─C≡N and ─C═O, on PAMA, which are conducive to adsorbing lithium polysulfide. The S@PAMA electrode is tested and maintained a capacity value of 628.7 mAh g-1 after long-term cycling, confirming its ability to effectively suppress the shuttle effect.

A Chemoproteomic Approach to Monitor Native Iron-Sulfur Cluster Binding.

Iron-sulfur (Fe-S) clusters are essential redox-active metallocofactors participating in electron transfer, radical chemistry, primary metabolism, and gene regulation. Successful trafficking and incorporation of Fe-S clusters into target proteins are critical to proper cellular function. While biophysical studies of isolated Fe-S proteins provide insight into the structure and function of these inorganic cofactors, few strategies currently exist to directly interrogate Fe-S cluster binding within a cellular environment. Here, we describe a chemoproteomic platform to report on Fe-S cluster incorporation and occupancy directly within a native proteome, enabling the characterization of Fe-S biogenesis pathways and the identification of undiscovered Fe-S proteins.

Sulfur dioxide inhibits mast cell degranulation by sulphenylation of galectin-9 at cysteine 74.

Objectives: Mast cell (MC) degranulation is a key process in allergic reactions and inflammatory responses. Aspartate aminotransferase 1 (AAT1)-derived endogenous sulfur dioxide (SO2) is an important regulator of MC function. However, the mechanism underlying its role in MC degranulation remains unclear. This study aimed to investigate the mechanism by which endogenous SO2 controlled MC degranulation. Methods: HMC-1 and Rat basophilic leukemia cell MC line (RBL-2H3) were used in the cell experiments. SO2 content was detected by in situ fluorescent probe. MC degranulation represented by the release rate of MC ß-hexosaminidase was determined using a colorimetric assay. Sulfenylation of galectin-9 (Gal-9) in MCs and purified protein was detected using a biotin switch assay. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to determine the exact sulfenylation sites of Gal-9 by SO2. Animal models of passive cutaneous anaphylaxis (PCA) and hypoxia-driven pulmonary vascular remodeling were used to investigate the effect of SO2 on mast cell activation in vivo. Site-directed mutation of Gal-9 was conducted to confirm the exact site of SO2 and support the significance of SO2/Gal-9 signal axis in the regulation of MC degranulation. Results: Degranulation was increased in AAT1-knockdowned MCs, and SO2 supplementation reversed the increase in MC degranulation. Furthermore, deficiency of endogenous SO2 contributed to IgE-mediated degranulation in vitro. Besides, SO2 inhibited IgE-mediated and hypoxia-driven MC degranulation in vivo. Mechanistically, LC-MS/MS analysis and site-directed mutation results showed that SO2 sulfenylated Gal-9 at cysteine 74. Sulfenylation of the 74th cysteine of Gal-9 protein was required in the SO2-inhibited MC degranulation under both physiological and pathophysiological conditions. Conclusion: These findings elucidated that SO2 inhibited MC degranulation via sulfenylating Gal-9 under both physiological and pathophysiological conditions, which might provide a novel treatment approach for MC activation-related diseases.

Phenotype-driven assessment of the ancestral trajectory of sulfur biooxidation in the thermoacidophilic archaea Sulfolobaceae.

Certain members of the family Sulfolobaceae represent the only archaea known to oxidize elemental sulfur, and their evolutionary history provides a framework to understand the development of chemolithotrophic growth by sulfur oxidation. Here, we evaluate the sulfur oxidation phenotype of Sulfolobaceae species and leverage comparative genomic and transcriptomic analysis to identify the key genes linked to sulfur oxidation. Metabolic engineering of the obligate heterotroph Sulfolobus acidocaldarius revealed that the known cytoplasmic components of sulfur oxidation alone are not sufficient to drive prolific sulfur oxidation. Imaging analysis showed that Sulfolobaceae species maintain proximity to the sulfur surface but do not necessarily contact the substrate directly. This indicates that a soluble form of sulfur must be transported to initiate cytoplasmic sulfur oxidation. Conservation patterns and transcriptomic response implicate an extracellular tetrathionate hydrolase and putative thiosulfate transporter in a newly proposed mechanism of sulfur acquisition in the Sulfolobaceae.IMPORTANCESulfur is one of the most abundant elements on earth (2.9% by mass), so it makes sense that the earliest biology found a way to use sulfur to create and sustain life. However, beyond evolutionary significance, sulfur and the molecules it comprises have important technological significance, not only in chemicals such as sulfuric acid and in pyritic ores containing critical metals but also as a waste product from oil and gas production. The thermoacidophilic Sulfolobaceae are unique among the archaea as sulfur oxidizers. The trajectory for how sulfur biooxidation arose and evolved can be traced using experimental and bioinformatic analyses of the available genomic data set. Such analysis can also inform the process by which extracellular sulfur is acquired and transported by thermoacidophilic archaea, a phenomenon that is critical to these microorganisms but has yet to be elucidated.

Enhancing refinery heavy oil fractions analytical performance through real-time predicative modeling.

This study introduces a suite of robust models aimed to advance the determination of physiochemical properties in heavy oil refinery fractions. By integrating real-time analytical technique inside the refinery analysis, we have developed a single analyzer capable of employing six partial least square regression equations. These designed models enable to provide real-time prediction of critical petroleum properties, such as sulfur content, micro carbon residues (MCR), asphaltene content, heating value, and the concentrations of nickel and vanadium metals. Specifically tailored for heavy oil in refinery feeds with an American petroleum institute (API) gravity range of 3° to 32° and sulfur content of 2.8 to 5.5 wt%, the models streamline the analysis process within refinery operations, bridging the gap between catalytic and non-catalytic processes across refinery units. The accuracy of our physiochemical prediction models has been validated against American Society for Testing and Materials (ASTM) standards, demonstrating their capability to deliver precise real-time property values. This approach not only enhances the efficiency of refinery analysis but also sets a new standard for the monitoring and optimization of heavy oil processing in real-time approach.

A unique three-dimensional network double-core-shell structure S@MnO2@MXene suppresses the shuttle effect in high-sulfur-content high-performance lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries represent the most promising next-generation energy storage systems because of their high theoretical specific capacity and energy density. However, the severe shuttle effect and volume expansion of sulfur cathodes have impeded their commercial viability. Hence, accelerating the conversion of lithium polysulfides (LiPSs) is crucial for achieving efficient Li-S batteries. In this study, we employ a straightforward electrostatic self-assembly method to coat ultra-thin MXene nanosheets onto a S@MnO2 core-shell structure, resulting in a highly conductive three-dimensional network. This unique structure not only suppresses the diffusion of LiPSs but also accelerates electron and ion transfer, ensuring a rapid and efficient conversion of LiPSs. The CV curves of symmetrical cells and the Li2S deposition curves demonstrate a significant improvement in the catalytic performance of batteries with S@MnO2@MXene. The capacity of Li-S batteries achieved an impressive 842 mAh/g at the current density of 1C, with a minimal capacity decay of only 0.84 mAh/g per cycle within 500 cycles. Additionally, increasing the sulfur loading mass to 5.88 mg cm-2 resulted in an areal capacity of 6.33 mAh cm-2, demonstrating practical application potential.

A multifunctional solution to enhance capacity and stability in lithium-sulfur batteries: Incorporating hollow CeO2 nanorods into carbonized non-woven fabric as an interlayer.

Lithium-sulfur batteries (LSBs) hold promise as the next-generation lithium-ion batteries (LIBs) due to their ultra-high theoretical capacity and remarkable cost-efficiency. However, these batteries suffer from the serious shuttle effect, challenging their practical application. To address this challenge, we have developed a unique interlayer (HCON@CNWF) composed of hollow cerium oxide nanorods (CeO2) anchored to carbonized non-woven viscose fabric (CNWF), utilizing a straightforward template method. The prepared interlayer features a three-dimensional (3D) conductive network that serves as a protective barrier and enhances electron/ion transport. Additionally, the CeO2 component effectively chemisorbs and catalytically transforms lithium polysulfides (LiPSs), offering robust chemisorption and activation sites. Moreover, the unique porous structure of the HCON@CNWF not only physically adsorbs LiPSs but also provides ample space for sulfur's volume expansion, thus mitigating the shuttle effect and safeguarding the electrode against damage. These advantages collectively contribute to the battery's outstanding electrochemical performance, notably in retaining a reversible capacity of 80.82 % (792 ± 5.60 mAh g-1) of the initial value after 200 charge/discharge cycles at 0.5C. In addition, the battery with HCON@CNWF interlayer has excellent electrochemical performance at high sulfur loading (4 mg cm-2) and low liquid/sulfur ratio (7.5 µL mg-1). This study, thus, offers a novel approach to designing advanced interlayers that can enhance the performance of LSBs.

Structures and Electron Transport Paths in the Four Families of Flavin-Based Electron Bifurcation Enzymes.

Oxidoreductases facilitating electron transfer between molecules are pivotal in metabolic pathways. Flavin-based electron bifurcation (FBEB), a recently discovered energy coupling mechanism in oxidoreductases, enables the reversible division of electron pairs into two acceptors, bridging exergonic and otherwise unfeasible endergonic reactions. This chapter explores the four distinct FBEB complex families and highlights a decade of structural insights into FBEB complexes. In this chapter, we discuss the architecture, electron transfer routes, and conformational changes across all FBEB families, revealing the structural foundation that facilitate these remarkable functions.

MarR family proteins sense sulfane sulfur in bacteria.

Members of the multiple antibiotic resistance regulator (MarR) protein family are ubiquitous in bacteria and play critical roles in regulating cellular metabolism and antibiotic resistance. MarR family proteins function as repressors, and their interactions with modulators induce the expression of controlled genes. The previously characterized modulators are insufficient to explain the activities of certain MarR family proteins. However, recently, several MarR family proteins have been reported to sense sulfane sulfur, including zero-valent sulfur, persulfide (R-SSH), and polysulfide (R-SnH, n ≥ 2). Sulfane sulfur is a common cellular component in bacteria whose levels vary during bacterial growth. The changing levels of sulfane sulfur affect the expression of many MarR-controlled genes. Sulfane sulfur reacts with the cysteine thiols of MarR family proteins, causing the formation of protein thiol persulfide, disulfide bonds, and other modifications. Several MarR family proteins that respond to reactive oxygen species (ROS) also sense sulfane sulfur, as both sulfane sulfur and ROS induce the formation of disulfide bonds. This review focused on MarR family proteins that sense sulfane sulfur. However, the sensing mechanisms reviewed here may also apply to other proteins that detect sulfane sulfur, which is emerging as a modulator of gene regulation.

Defect Density and Atomic Defect Recognition in the Middle Layer of a Trilayer MoS2 Stack.

Molybdenum disulfide (MoS2) is one of the most intriguing two-dimensional materials, and moreover, its single atomic defects can significantly alter the properties. These defects can be both imaged and engineered using spherical and chromatic aberration-corrected high-resolution transmission electron microscopy (CC/CS-corrected HRTEM). In a few-layer stack, several atoms are vertically aligned in one atomic column. Therefore, it is challenging to determine the positions of missing atoms and the damage cross-section, particularly in the not directly accessible middle layers. In this study, we introduce a technique for extracting subtle intensity differences in CC/CS-corrected HRTEM images. By exploiting the crystal structure of the material, our method discerns chalcogen vacancies even in the middle layer of trilayer MoS2. We found that in trilayer MoS2 the middle layer's damage cross-section is about ten times lower than that in the monolayer. Our findings could be essential for the application of few-layer MoS2 in nanodevices.

Promoting Polysulfide Redox Reactions through Electronic Spin Manipulation.

Catalytic additives able to accelerate the lithium-sulfur redox reaction are a key component of sulfur cathodes in lithium-sulfur batteries (LSBs). Their design focuses on optimizing the charge distribution within the energy spectra, which involves refinement of the distribution and occupancy of the electronic density of states. Herein, beyond charge distribution, we explore the role of the electronic spin configuration on the polysulfide adsorption properties and catalytic activity of the additive. We showcase the importance of this electronic parameter by generating spin polarization through a defect engineering approach based on the introduction of Co vacancies on the surface of CoSe nanosheets. We show vacancies change the electron spin state distribution, increasing the number of unpaired electrons with aligned spins. This local electronic rearrangement enhances the polysulfide adsorption, reducing the activation energy of the Li-S redox reactions. As a result, more uniform nucleation and growth of Li2S and an accelerated liquid-solid conversion in LSB cathodes are obtained. These translate into LSB cathodes exhibiting capacities up to 1089 mA h g-1 at 1 C with 0.017% average capacity loss after 1500 cycles, and up to 5.2 mA h cm-2, with 0.16% decay per cycle after 200 cycles in high sulfur loading cells.

Effects of sulfur dioxide fumigation on mortality of confused flour beetle (Coleoptera: Tenebrionidae) and rice weevil (Coleoptera: Curculionidae).

Sulfur dioxide (SO2) fumigation was studied in laboratory to determine its potential as an alternative treatment for postharvest control of stored product insects, confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae), and rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Three-hour fumigations with 0.1%-2.0% SO2 were conducted against eggs, immature stages, and adults of the 2 insects at 20 °C. Effective control of both insects was achieved. However, there were considerable variations between the 2 insects and among different life stages. Confused flour beetle was more susceptible to SO2 fumigation than rice weevil. Complete control of adults and all life stages of confused flour beetle was achieved in 3-h fumigations with 0.5% and 2.0% SO2, respectively. For rice weevil, 3-h fumigation with 1.5% SO2 resulted in 96.5% adult mortality and the fumigation with 2.0% SO2 resulted in 99.27% mortality of adults and 87.5% mortality of immature stages. Three-hour fumigations with 1% SO2 resulted in <5% egg survival to adults. The study demonstrated high efficacy of SO2 fumigation against the insects and suggested that SO2 fumigation has good potential for postharvest pest control on stored products.

Combined effects of nitrogen and sulfur fertilizers on chemical composition, structure and physicochemical properties of buckwheat starch.

Buckwheat starch has attracted worldwide attention in the food industry as a valuable raw material or food additive. Nitrogen (N) and sulfur (S) are two nutrients essential to ensure grain quality. This study investigated the combined application of N fertilizer (0, 45 and 90 kg N ha-1) and S fertilizer (0 and 45 kg SO3 ha-1) on the chemical composition, structure and physicochemical properties of buckwheat starch. The results showed that increasing the fertilizer application decreased amylose content and starch granule size but increased light transmittance, water solubility and swelling power. The stability of the absorption peak positions and the decrease in short-range order degree suggested that fertilization influenced the molecular structure of buckwheat starch. In addition, increases in viscosity and gelatinization enthalpy as well as decreases in gelatinization temperatures and dynamic rheological properties indicated changes in the processing characteristics and product quality of buckwheat-based foods.

Optimization of a Novel Engineered Ecosystem Integrating Carbon, Nitrogen, Phosphorus, and Sulfur Biotransformation for Saline Wastewater Treatment Using an Interpretable Machine Learning Approach.

The denitrifying sulfur (S) conversion-associated enhanced biological phosphorus removal (DS-EBPR) process for treating saline wastewater is characterized by its unique microbial ecology that integrates carbon (C), nitrogen (N), phosphorus (P), and S biotransformation. However, operational instability arises due to the numerous parameters and intricates bacterial interactions. This study introduces a two-stage interpretable machine learning approach to predict S conversion-driven P removal efficiency and optimize DS-EBPR process. Stage one utilized the XGBoost regression model, achieving an R2 value of 0.948 for predicting sulfate reduction (SR) intensity from anaerobic parameters with feature engineering. Stage two involved the CatBoost classification and regression model integrating anoxic parameters with the predicted SR values for predicting P removal, reaching an accuracy of 94% and an R2 value of 0.93, respectively. This study identified key environmental factors, including SR intensity (20-45 mg S/L), influent P concentration (<9.0 mg P/L), mixed liquor volatile suspended solids (MLVSS)/mixed liquor suspended solids (MLSS) ratio (0.55-0.72), influent C/S ratio (0.5-1.0), anoxic reaction time (5-6 h), and MLSS concentration (>6.50 g/L). A user-friendly graphic interface was developed to facilitate easier optimization and control. This approach streamlines the determination of optimal conditions for enhancing P removal in the DS-EBPR process.