Effects of sliver nanoparticles on nitrogen removal by the heterotrophic nitrification-aerobic denitrification bacteria Zobellella sp. B307 and their toxicity mechanisms.

Due to the widespread use of sliver nanoparticles (AgNPs), a large amount of AgNPs has inevitably been released into the environment, and there is growing concern about the toxicity of AgNPs to nitrogen-functional bacteria. In addition to traditional anaerobic denitrifying bacteria, heterotrophic nitrification-aerobic denitrification (HNAD) bacteria are also important participants in the nitrogen cycle. However, the mechanisms by which AgNPs influence HNAD bacteria have yet to be explicitly demonstrated. In this study, the inhibitory effects of different concentrations of AgNPs on a HNAD bacteria Zobellella sp. B307 were investigated, and the underlying mechanism was explored by analyzing the antioxidant system and the activities of key denitrifying enzymes. Results showed that AgNPs could inhibit the growth and the HNAD ability of Zobellella sp. B307. AgNPs could accumulate on the surface of bacterial cells and significantly destroyed the cell membrane integrity. Further studies demonstrated that the presence of high concentration of AgNPs could result in the overproduction of reactive oxygen species (ROS) and related oxidative stress in the cells. Furthermore, the catalytic activities of key denitrifying enzymes (nitrate reductase (NAR), nitrite reductase (NIR), and nitrous oxide reductase (N2OR)) were significantly suppressed under exposure to a high concentration of AgNPs (20 mg·L-1), which might be responsible for the inhibited nitrogen removal performance of strain B307. This work could improve our understanding of the inhibitory effect and underlying mechanism of AgNPs on HNAD bacteria.

Effect of light intensity and photoperiod on high-value production and nutrient removal performance with bacterial-algal coupling system.

Direct discharge of mariculture wastewater can lead to eutrophication, posing a threat to aquatic ecosystems. A novel Bacteria-Algae Coupled Reactor (BACR) offers advantages in treating mariculture wastewater, which can effectively remove pollutants while simultaneously obtaining microalgal products. However, there is limited information available on how illumination affects the cultivation of mixotrophic microalgae in this bacteria-algae coupling system. Therefore, a combined strategy of photoperiod and light intensity regulation was employed to improve the biological mariculture wastewater remediation, promote microalgae biomass accumulation, and increase the high-value product yield in this study. Optimal light conditions could effectively enhance microalgal carbohydrate, protein, lipid accumulation and photosynthetic activity, with the carbohydrate, protein and lipid contents reached 44.11, 428.57 and 399.68 mg/L, respectively. Moreover, excellent removal rates were achieved for SCOD, NH4+-N and TP, reaching 86.68%, 87.35% and 95.13% respectively. This study proposes a comprehension of BACR processes in mariculture wastewater under different light conditions.

Effect of light intensity on nitrogen transformation, enzymatic activity, antioxidant system and transcriptional response of Chlorella pyrenoidosa during treating mariculture wastewater.

The nitrogen transformation, enzymatic activity, antioxidant ability and transcriptional response of Chlorella pyrenoidosa (C. pyrenoidosa) treating mariculture wastewater were compared under different light intensities. The microalgal growth, chlorophyll synthesis and nitrogen removal ability of C. pyrenoidosa increased with the light intensity from 3000 to 7000 Lux, whereas they slightly decreased under 9000 and 11,000 Lux. The nitrogen metabolism enzymatic activities displayed obvious differences under different light intensities and affected the nitrogen transformation process. The reactive oxygen species (ROS) production increased with the increase of operational time, whereas it had distinct differences under different light intensities. The changes of antioxidant enzymatic activities were positively correlated with the ROS production. The transcriptional response of C. pyrenoidosa was in accordance with the variation of the photosynthesis, nitrogen assimilation and antioxidant system under different light intensities. This study provides theoretical basis and technical support to select suitable light intensity for algae treating mariculture wastewater.

Removal of tetracycline by ultraviolet/sodium percarbonate (UV/SPC)advanced oxidation process in water.

Tetracycline (TC) was widely used and frequently detected in various water bodies, where the presence of TC posed a significant threat to the health of aquatic organisms. Furthermore, antibiotics were hardly degraded by biological treatment. Thus, in order to enhance the removal of TC, we proposed the use of a novel ultraviolet/sodium percarbonate (UV/SPC) advanced oxidation process and initiated an in-depth study. The study investigated the influence of oxidant dosage, initial pH, UV intensity, and TC concentration on the removal of TC. The results demonstrated that the UV/SPC system efficiently removed TC, with removal efficiency increasing as the SPC concentration increased. Within the pH range of 3-11, TC degradation exhibited minimal variation, indicating the UV/SPC system's strong adaptability to pH variations. The research on the impact of the water matrix on TC removal revealed that HCO3- had an inhibitory effect on TC degradation, while NO3- promoted TC degradation. Additionally, the presence of free radical species (·OH, ·CO3-, ·O2-) were detected and rate constants for the secondary reactions (k·OH,TC = 6.3 × 109 L mol-1·s-1, k·CO3-,TC = 3.4 × 108 L mol-1·s-1) were calculated, indicating that ·OH exhibited a stronger oxidative performance compared to ·CO3-. This study did not only present a novel strategy via UV/SPC to remove TC but also uncovered the unique role of ·CO3- for contaminant removal.

Rapid Induction of Long-Lasting Systemic and Mucosal Immunity via Thermostable Microneedle-Mediated Chitosan Oligosaccharide-Encapsulated DNA Nanoparticles.

Most existing vaccines, delivered by intramuscular injection (IM), are typically associated with stringent storage requirements under cold-chain distribution and professional administration by medical personnel and often result in the induction of weak mucosal immunity. In this context, we reported a microneedle (MN) patch to deliver chitosan oligosaccharide (COS)-encapsulated DNA vaccines (DNA@COS) encoding spike and nucleocapsid proteins of SARS-CoV-2 as a vaccination technology. Compared with IM immunization, intradermal administration via the MN-mediated DNA vaccine effectively induces a comparable level of neutralizing antibody against SARS-CoV-2 variants. Surprisingly, we found that MN-mediated intradermal immunization elicited superior systemic and mucosal T cell immunity with enhanced magnitude, polyfunctionality, and persistence. Importantly, the DNA@COS nanoparticle vaccine loaded in an MN patch can be stored at room temperature for at least 1 month without a significant decrease of its immunogenicity. Mechanically, our strategy enhanced dendritic cell maturation and antiviral immunity by activating the cGAS-STING-mediated IFN signaling pathway. In conclusion, this work provides valuable insights for the rapid development of an easy-to-administer and thermostable technology for mucosal vaccines.

Effect of mariculture wastewater concentrations on high-value production and pollutants removal with bacterial-algal coupling reactor (BACR).

To achieve the goal of cost-effective mariculture wastewater treatment, a novel Bacteria-Algae Coupling Reactor (BACR) integrating acidogenic fermentation with microalgae cultivation was applied for the mariculture wastewater treatment. Currently, there is limited research on the impact of different concentrations of mariculture wastewater on the pollutant removal and the high-value products recovery. In this study, different concentrations (4, 6, 8, and 10 g/L) of mariculture wastewater were treated with BACR. The results showed thatoptimalMW concentrations of 8 g/L improved the growth viability and biochemical components synthetic of Chlorella vulgaris, which increased the potential for high-value products recovery. The BACR exhibited the excellent removal efficiency of chemical oxygen demand, ammonia-nitrogen and total phosphorus with 82.30%, 81.12% and 96.40%, respectively. This study offers an ecological and economic approach to improve the MW treatment through the utilization of a novel bacterial-algal coupling system.

Enhancement of SARS-CoV-2 N Antigen-Specific T Cell Functionality by Modulating the Autophagy-Mediated Signal Pathway in Mice.

The frequent SARS-CoV-2 variants have caused a continual challenge, weakening the effectiveness of current vaccines, and thus it is of great importance to induce robust and conserved T cellular immunity for developing the next-generation vaccine against SARS-CoV-2 variants. In this study, we proposed a conception of enhancing the SARS-CoV-2 specific T cell functionality by fusing autophagosome-associated LC3b protein to the nucleocapsid (N) (N-LC3b). When compared to N protein alone, the N-LC3b protein was more effectively targeted to the autophagosome/lysosome/MHC II compartment signal pathway and thus elicited stronger CD4+ and CD8+ T cell immune responses in mice. Importantly, the frequency of N-specific polyfunctional CD4+ and CD8+ T cells, which can simultaneously secrete multiple cytokines (IFN-γ+/IL-2+/TNF-α+), in the N-LC3b group was significantly higher than that in the N alone group. Moreover, there was a significantly improved T cell proliferation, especially for CD8+ T cells in the N-LC3b group. In addition, the N-LC3b also induced a robust humoral immune response, characterized by the Th1-biased IgG2a subclass antibodies against the SARS-CoV-2 N protein. Overall, these findings demonstrated that our strategy could effectively induce a potential SARS-CoV-2 specific T cellular immunity with enhanced magnitude, polyfunctionality, and proliferation, and thus provided insights to develop a promising strategy for the design of a novel universal vaccine against SARS-CoV-2 variants and other emerging infectious diseases.

Elucidating microalgae-mediated metabolism for sulfadiazine removal mechanism and transformation pathways.

Sulfadiazine (SDZ) as a typical sulfonamide antibiotic is commonly detected in wastewater, and its removal mechanism and transformation pathways in microalgae-mediated system remain unclear. In this study, the SDZ removal through hydrolysis, photodegradation, and biodegradation by Chlorella pyrenoidosa was investigated. Higher superoxide dismutase activity and biochemical components accumulation were obtained under SDZ stress. The SDZ removal efficiencies at different initial concentrations were 65.9-67.6%, and the removal rate followed pseudo first-order kinetic model. Batch tests and HPLC-MS/MS analyses suggested that biodegradation and photodegradation through the reactions of amine group oxidation, ring opening, hydroxylation, and the cleavage of S-N, C-N, C-S bond were dominant removal mechanisms and pathways. Characteristics of transformation products were evaluated to analyze their environmental impacts. High-value products of lipid, carbohydrate, and protein in microalgae biomass presented economic potential of microalgae-mediated metabolism for SDZ removal. The findings of this study broadened the knowledge for the microalgae self-protection from SDZ stress and provided a deep insight into SDZ removal mechanism and transformation pathways.

Platymonas helgolandica-driven nitrogen removal from mariculture wastewater under different photoperiods: Performance evaluation, enzyme activity and transcriptional response.

The nitrogen removal performance and biological mechanism of Platymonas helgolandica var. Tsingtaoensis (P. helgolandica) were investigated in treating mariculture wastewater under different light: dark (L:D) photoperiods. The growth of P. helgolandica was positively correlated with the photoperiods from 6L:18D to 15L:9D, and the highest photosynthetic activity appeared under 6L:18D photoperiod on day 3. P. helgolandica exhibited the highest removal efficiencies of total nitrogen and COD at 89 % and 93 % under 15L:9D photoperiod, respectively. NH4+-N assimilation was proportional to the photoperiods from 6L:18D to 15L:9D and longer illumination promoted NO2--N removal. However, the highest NO3--N reduction rate was achieved under 12L:12D photoperiod. The different nitrogen-transformed enzymatic activities were affected by photoperiod. Transcriptome revealed that unigenes were enriched in nitrogen metabolism and photosynthesis pathways, of which the functional gene expression was up-regulated significantly. This study provides insights into the optimization of photoperiod for mariculture wastewater treatment by P. helgolandica.

Impact of aerobic/anoxic alternation number on performance, microbial community and functional genes of sequencing batch biofilm reactor treating mariculture wastewater.

The performance, microbial community and functional genes of a sequencing batch biofilm reactor (SBBR) were investigated in treating mariculture wastewater under different aerobic/anoxic alternation number. The removal efficiency of chemical oxygen demand (COD) and NH4+-N kept at 95.66 ± 1.83 % and 90.28 ± 2.42 % under aerobic/anoxic alternation number between 1 and 4. The total nitrogen (TN) removal efficiency gradually decreased from 94.45 ± 1.12 % to 83.06 ± 1.25 % with the increase of aerobic/anoxic alternative number from 1 to 4. The nitrification rates and their corresponding enzymatic activities increased slightly with the increase of aerobic/anoxic alternation number, whereas the denitrifying process had the contrary results. The variation of aerobic/anoxic alternation number obviously affected the microbial diversity and abundance. The microbial network structure and keystone taxa were different under different aerobic/anoxic alternation number. The functional genes abundance for the denitrification pathway decreased with the increase of aerobic/anoxic alternation number.

The acceptance of SARS-CoV-2 rapid antigen self-testing: A cross-sectional study in China.

Compared with the nucleic acid amplification test (NATT), the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid antigen self-testing (RAST) has advantages in speed and convenience. However, little is known about people's acceptance and influencing factors for SARS-CoV-2 RAST. A cross-sectional study was conducted from April 21 to 30, 2022 in China. The χ2 test and multivariate logistic regressions were used to identify the influencing factors. The structural equation model was used to test the extended protective motivation theory (PMT) model hypotheses. Among the total of 5107 participants, 62.5% were willing to accept the SARS-CoV-2 RAST. There were significant differences in acceptance among different residences (p < 0.001), educational level (p < 0.001), occupation (p < 0.001), monthly income (p < 0.001), travel frequency (p < 0.05), and feelings about NATT (p < 0.001). Response efficacy (ß = 0.05; p = 0.025) and self-efficacy (ß = 0.84; p < 0.001) had a positive effect, while response cost showed a negative effect (ß = -0.07; p < 0.001). The public's major concerns about SARS-CoV-2 RAST are its reliability, testing method, price, and authority. Overall, a moderate intention to use SARS-CoV-2 RAST was found among the Chinese population. The extended PMT can be used for the prediction of intention to accept the RAST. We need to take measures to increase people's acceptance of SARS-CoV-2 RAST.

Insight into characteristics of sulphur-based autotrophic denitrifying microbiota in the nitrate removal.

Mariculture wastewater is characterized by low organic carbon to nitrogen ratio (C/N) but high nitrate concentration, which makes it difficult to remove nitrate by the completely heterotrophic denitrification. However, high nitrate discharge poses a threat to the natural environment and human health. Thus, we enriched sulphur-based autotrophic denitrifying (SAD) microbiota and optimized the nitrate removal under different environmental factors and electron donor conditions. The results showed that the dominant genera in the enriched microbiota were previously confirmed autotrophic denitrifiers, Sulfurovum, Thioalkalispira-Sulfurivermis, and Sedimenticola, with a high relative abundance of 41.14%, 21.01%, and 6.17%. Among the environmental factors, pH was the key factor affecting SAD microbiota, and pH 7-9 favoured nitrate removal. However, high pH led to nitrite accumulation (e.g. 10 mg/L at pH = 9), which should be strictly avoided. With regard to electron donors, the optimal concentrations of thiosulphate and nitrate were 50 and 5 mg/L, respectively. The best organic carbon is acetate with an optimal concentration of 10 mg/L. Meanwhile, the initial concentration of thiosulphate was proportional to the nitrate removal rate, while higher concentrations of organic carbon stimulated the heterotrophic denitrification potential of microbiota and thus benefited to dentrification. This study showed that the enriched SAD microbiota was able to achieve efficient nitrate removal under suitable environmental conditions and mixed electron donors and thus presented the potential for application in the treatment of mariculture wastewater.

Focus on the role of synthetic phytohormone for mixotrophic growth and lipid accumulation by Chlorella pyrenoidosa.

Synthetic phytohormone (SP) is regarded as an attractive candidate for microalgae cultivation due to its potential for high-value microalgae biomass production. Herein, α-naphthylacetic acid (NAA), indomethacin (IN) and 2,4-dichlorophenoxyacetic acid (2,4-D) were used for the mixotrophic cultivation of Chlorella pyrenoidosa with mariculture wastewater (MW) acidogenic fermentation effluent. The growth and lipid accumulation of Chlorella pyrenoidosa added with SP were enhanced, given their high bioavailability of the nutrients. Among these three SPs, IN was optimal for Chlorella pyrenoidosa growth, with the maximum optical density of 1.81. NAA exhibited the best performance for lipid production and the proportion of lipid reached 50.24%. Furthermore, the energy of Chlorella pyrenoidosa cultured with SP preferentially allocated to lipogenesis. To understand the mechanism of lipid accumulation in Chlorella pyrenoidosa in response to SP, the enzyme activities involved in carbon metabolism were determined. The malic enzyme (ME) and acetyl-CoA carboxylase (ACCase) were positively correlated with lipid accumulation. Phosphoenolpyruvate carboxylase (PEPC) was the negative feedback enzyme for lipid synthesis. The findings could provide valuable information for regulation mechanism of lipid accumulation and value-added products recovery by microalgae.

Effect of external carbon addition and enrofloxacin on the denitrification and microbial community of sequencing batch membrane reactor treating synthetic mariculture wastewater.

The effect of sequencing batch membrane bioreactor (SMBR) on external carbon addition and enrofloxacin was investigated to treat synthetic mariculture wastewater. Anoxic/anaerobic and low COD/TN can improve the ammonia oxidation of the system, and the NH4+-N removal efficiency above 99%. External carbon was added and an anoxic environment was set to provide a suitable environment for denitrifying bacteria. When the external carbon source was 50-207 mg/L, the TN removal efficiency (31.82%-37.73%) and the COD of the effluent (28.85-36.58 mg/L) had little change. The partition resistance model showed that cake deposition resistance (RC,irr) and irreversible resistance (RPB) were the main components. And with the increase in cleaning times, the fouling rate of membrane components accelerated. Enrofloxacin can promote the TN removal efficiency (45.66%-93.74%) and had a significant effect on TM7a, Cohaesibacter, Vibrio and Phaeobacter.

Metagenomic analysis and nitrogen removal performance evaluation of activated sludge from a sequencing batch reactor under different salinities.

The effect of salinity on the nitrogen removal performance and microbial community of activated sludge was investigated in a sequencing batch reactor. The NH4+-N removal efficiency was over 95% at 0-4% salinity, indicating that the nitrification performance of activated sludge was slightly affected by lower salinity. The obvious nitrite accumulation was observed with the increment of the salinity to 5%, followed by a notable decline in the nitrogen removal performance at 6% salinity. The salinity inhibited the microbial activity, and the specific rate of nitrification and denitrification was decreased by the increasing salinity obviously. Additionally, the lower activity of superoxide dismutase and peroxidase and higher reactive oxygen species content in activated sludge might account for the deteriorative nitrogen removal performance at 6% salinity. Metagenomics analysis revealed that the genes encoding the ABC-type quaternary amine transporter in the ABC transporter pathway were abundant in the activated sludge at 2% and 4% salinity, and the higher salinity of 6% led to the loss of the genes encoding the p-type Na+ transporter in the ABC transporter pathway. These results indicated that the salinity could weaken the ABC transporter pathway for the balance of osmotic pressure in activated sludge. The microbial activity and nitrogen removal performance of activated sludge were decreased due to the unbalanced osmotic pressure at higher salinity.

Enhancing two-phase anaerobic digestion of mixture of primary and secondary sludge by adding granular activated carbon (GAC): Evaluating acidogenic and methanogenic efficiency.

Although the granular activated carbon (GAC) has been proved to enhance conventional single-phase anaerobic digestion (AD), how it impacts on acidogenic and methanogenic fermentation is still unknown. In this study, GAC was introduced to elevate the efficiency of two-phase AD, with mixture of primary and secondary sludge as substrate. Five dosages: 0, 0.1, 0.3, 0.5 and 0.7 g GAC/g TSS (Total Suspended Solids) were investigated to determine influences of GAC. The variations of biogas (hydrogen and methane), volatile fatty acids (VFAs), organics degradation and transformation in extracellular polymeric substances (EPS) and dissolved organic matters (DOM) were analyzed. Modified Gompertz model and first-order reaction equation was applied to analyze the kinetics of biogas yield and VFAs utilization, respectively. Sludge reduction, electrical conductance and pH were also quantified to evaluate the system performance. The results showed that GAC could improve two-phase AD performance by enhancing methane production and organics conversion.

Impact of sulfamethoxazole and organic supplementation on mixotrophic denitrification process: Nitrate removal efficiency and the response of functional microbiota.

Recirculating aquaculture systems (RAS) effluent is characterized by low COD to total inorganic nitrogen ratio (C/N), excessive nitrate, and the presence of traces of antibiotics. Hence, it urgently needs to be treated before recycling or discharging. In this study, four denitrification bioreactors at increasing C/N ratios (0, 0.7, 2, and 5) were started up to treat mariculture wastewater under the sulfamethoxazole (SMX) stress, during which the bioreactors performance and the shift of mixotrophic microbial communities were explored. The result showed that during the SMX exposure, organic supplementation enhanced nitrate and thiosulfate removal, and eliminated nitrite accumulation. The denitrification rate was accelerated by increasing C/N from 0 to 2, while it declined at C/N of 5. The decline was ascribed to which SMX reduced the relative abundance of denitrifiers, but improved the capability of dissimilatory nitrogen reduction to ammonia (DNRA) and sulfide production. The direct evidence was the relative abundance of sulfidogenic populations, such as Desulfuromusa, Desulfurocapsa, and Desulfobacter increased under the SMX stress. Moreover, high SMX (1.5 mg L-1) caused the obvious accumulation of ammonia at C/N of 5 due to the high concentration of sulfide (3.54 ± 1.08 mM) and the enhanced DNRA process. This study concluded that the mixotrophic denitrification process with the C/N of 0.7 presented the best performance in nitrate and sulfur removal and indicated the maximum resistance to SMX.

Anode modification of sediment microbial fuel cells (SMFC) towards bioremediating mariculture wastewater.

Remediation of mariculture wastewater is of great practical importance. In this study, sediment microbial fuel cells (SMFCs) were adopted and carbon felt anodes were modified to enhance COD and ammonia removal in mariculture system. The results showed that the SMFC anode with 5 % (w/w) graphene oxide (GO) coating performed best in pollutants removal and electricity generation. The maximum power density approached 132 mW/m2, nearly 4.5 times higher than the unmodified anode. The removal efficiency of COD and ammonia reached 82.1 % and 95.8 % respectively, both improved compared with the control and chemical modification. The modified anode effectively enriched the electrogenic Sulfurovum and Lactobacillus and thus led to a significant improvement in the electrochemical performance of SMFC. This study demonstrates the successful application of SMFCs with GO modified anodes in the in-situ removing pollutants and SMFCs present obvious remediation potential on the contaminated mariculture inhabitant.

Removal effect of enrofloxacin from mariculture sediments by bioelectrochemical system and analysis of microbial community structure.

Based on the application of sediment microbial fuel cell (SMFC) in the bioremediation of sediment, this study used the sediment microbial fuel cell technology as the leading reactor. Modification of anode carbon felts (CF) by synthesis of PANI/MnO2 composited to improve the electrical performance of the sediment microbial fuel cell. This study investigated the degradation effects, degradation pathways of the specific contaminant enrofloxacin and microbial community structure in sediment microbial fuel cell systems. The results showed that the sediment microbial fuel cell system with modified anode carbon felt (PANI-MnO2/CF) prepared by in-situ chemical polymerization had the best power production performance. The maximum output voltage was 602 mV and the maximum power density was 165.09 mW m-2. The low concentrations of enrofloxacin (12.81 ng g-1) were effectively degraded by the sediment microbial fuel cell system with a removal rate of 59.52%.

Insights into the response of anammox sludge to the combined stress of nickel and salinity.

Anaerobic ammonium oxidation (anammox) is a promising technology applied to treat industrial wastewater, while the commonly coexistent heavy metals and salinity usually become a challenging issue to be addressed. In this study, the responses of anammox sludge in terms of performance, activity, functional enzyme and extracellular polymeric substance (EPS) to the combined stress of Ni(II) and salinity (20 ‰) were investigated holistically. It turned out that low Ni(II) concentration (0.2 mg·L-1) together with salinity (20 ‰) showed an insignificant effect on the anammox performance, while a decreased nitrogen removal by 46.96 % was observed with the increased Ni(II) concentration to 1 mg·L-1. It should be pointed out that the anammox system exhibited good robustness evidenced by rapid recovery to achieve 89.13 % of nitrogen removal efficiency and 1.21 kg·m-3·d-1 of nitrogen removal rate after the elimination of stress factors within 40 days. Ni(II) concentration was revealed to play a more important role in the specific activity of anammox sludge. The functional enzymes related to nitrogen removal, e.g. nitrite reductase (NIR), hydrazine oxidase (HZO) and heme c were found to be inhibited by the combined stress of Ni(II) and salinity, with decreased activity by 49.54 %, 39.39 % and 45.88 %, respectively. However, the enzyme related to assimilation, e.g. alkaline phosphatase (AKP) and nitrate reductase (NAR) appeared to be enhanced. The EPS content was found to decrease by 55.19 % under the combined stress. Detailed analysis of 3D-EEM and FTIR spectra further revealed that the combined stress of Ni(II) and salinity could change both the quantity and composition of EPS in anammox sludge. These results are expected to offer insights into the combined effect of nickel and salinity on the anammox system, and benefit the application of anammox technology for industrial metal-rich saline wastewater treatment.