Performance evaluation and metagenomic analysis of sequencing batch reactor under transient 2,4,6-trichlorophenol shock.

The transient chlorophenol shock under some emergency conditions might directly affect the pollutant removal of bioreactor. Therefore, the recovery of bioreactor performance after transient chlorophenol shock is a noteworthy issue. In the present research, the performance, antioxidant response, microbial succession and functional genes of sequencing batch reactor (SBR) were evaluated under transient 2,4,6-trichlorophenol (2,4,6-TCP) shock. The chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) removal efficiencies decreased sharply in the first 4 days after 60 mg/L 2,4,6-TCP shock for 24 h and gradually recovered to normal in the subsequent 8 days. The nitrogen removal rates and their corresponding enzymatic activities rapidly decreased after transient 2,4,6-TCP shock and then gradually increased to normal. The increase of antioxidant enzymatic activity, Cu-Zn SOD genes and Fe-Mn SOD genes contributed to the recovery of SBR performance. The abundance of genes encoding ammonia monooxygenase and hydroxylamine dehydrogenase decreased after transient 2,4,6-TCP shock, including amoA, amoC and nxrA. Thauera, Dechloromonas and Candidatus_Competibacter played key roles in the restorative process, which provided stable abundances of narG, norB , norC and nosZ. The results will deeply understand into the effect of transient 2,4,6-TCP shock on bioreactor performance and provide theoretical basis to build promising recoveries strategy of bioreactor performance.

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.

Single-Cell Microgel Encapsulation Improves the Therapeutic Efficacy of Mesenchymal Stem Cells in Treating Intervertebral Disc Degeneration via Inhibiting Pyroptosis.

While mesenchymal stem cell (MSC) shows great potentials in treating intervertebral disc degeneration, most MSC die soon after intradiscal transplantation, resulting in inferior therapeutic efficacy. Currently, bulk hydrogels are the common solution to improve MSC survival in tissues, although hydrogel encapsulation impairs MSC migration and disrupts extracellular microenvironment. Cell hydrogel encapsulation has been proposed to overcome the limitation of traditional bulk hydrogels, yet this technique has not been used in treating disc degeneration. Using a layer-by-layer self-assembly technique, we fabricated alginate and gelatin microgel to encapsulate individual MSC for treating disc degeneration. The small size of microgel allowed intradiscal injection of coated MSC. We demonstrated that pyroptosis was involved in MSC death under oxidative stress stimulation, and microgel coating suppressed pyroptosis activation by maintaining mitochondria homeostasis. Microgel coating protected MSC in the harsh disc microenvironment, while retaining vital cellular functions such as migration, proliferation, and differentiation. In a rat model of disc degeneration, coated MSC exhibits prolonged retention in the disc and better efficacy of attenuating disc degeneration, as compared with bare MSC treatment alone. Further, microgel-coated MSC exhibited improved therapeutic effects in treating disc degeneration via suppressing the activation of pyroptosis in the disc. For the first time, microgel-encapsulated MSC was used to treat disc degeneration and obtain encouraging outcomes. The developed biocompatible single-cell hydrogel is an effective strategy to protect MSC and maintain cellular functions and may be an efficacious approach to improving the efficacy of MSC therapy in treating disc degeneration. The objective of this study is to improve the efficacy of cell therapy for treating disc degeneration using single-cell hydrogel encapsulation and further to understand related cytoprotective mechanisms.

Mechanochemically Reprogrammed Interface Orchestrates Neutrophil Bactericidal Activity and Apoptosis for Preventing Implant-Associated Infection.

The onset of implant-associated infection (IAI) triggers a cascade of immune responses, which are initially dominated by neutrophils. Bacterial aggregate formation and hypoxic microenvironment, which occur shortly after implantation, may be two major risk factors that impair neutrophil function and lead to IAI. Here, the implant surface with phytic acid-Zn2+ coordinated TiO2 nanopillar arrays (PA-Zn@TiNPs) and oxygen self-supporting CaO2 nanoparticles, named as CPZTs, is mechanochemically reprogrammed. The engineered CPZTs interface integrates multiple properties to inhibit the formation of nascent biofilm, encompassing antibacterial adhesion, mechanobactericidal effect, and chemobiocidal effect. Meanwhile, continuous oxygenation fuels the neutrophils with reactive oxygen species (ROS) for efficient bacterial elimination on the implant surface and inside the neutrophils. Furthermore, this surface modulation strategy accelerates neutrophil apoptosis and promotes M2 macrophage-mediated osteogenesis both in vitro and in a rat model of IAI. In conclusion, targeting neutrophils for immunomodulation is a practical and effective strategy to prevent IAI and promote bone-implant integration.

Hyperbranched polyphthalocyanine micelles with dual PTT/PDT functions for bacteria eradication under an NIR window.

A Zinc phthalocyanine-based (ZnPc-PA) polymeric micelle around 70 nm and with dual-modal PTT/PDT functions for non-antibiotic bacteria eradication was developed. It showed an excellent bacterial killing efficiency of 95.2% and 96.7% in vitro against Methicillin-resistant Staphylococcus aureus (MRSA) and its biofilm, respectively. Furthermore, the in vivo experiments proved its great potential for implant-associated infection (IAI).

Performance evaluation, enzymatic activity change and metagenomic analysis of sequencing batch reactor under divalent zinc stress.

Divalent zinc (Zn2+) are widely detected in domestic and industrial wastewater, and it is essential to evaluate the effect of Zn2+ on wastewater biological treatment process due to its bio-toxicity. In this study, the nitrogen removal rates and their corresponding enzymatic activities of sequencing batch reactor decreased with the increase of Zn2+ concentration. The Zn2+ accumulation in activated sludge caused significant antioxidant response, and the reactive oxygen species (ROS) production and antioxidant enzymatic activities were positively correlated with Zn2+ concentration. The presence of Zn2+ inhibited the metabolic pathways related to energy production and electron transport. The abundance decreases of nitrification and denitrification functional genes led to the deterioration of nitrogen removal performance under Zn2+ stress. The correlation analysis between functional gene modules and microbial genera revealed that Zoogloea had obvious Zn2+ resistance. This study can provide the insights into the influencing mechanism of Zn2+ on the biological nitrogen removal process.

A Redox Homeostasis Modulatory Hydrogel with GLRX3+ Extracellular Vesicles Attenuates Disc Degeneration by Suppressing Nucleus Pulposus Cell Senescence.

Characterized by nucleus pulposus (NP) cell senescence and extracellular matrix (ECM) degradation, disc degeneration is a common pathology for various degenerative spinal disorders. To date, effective treatments for disc degeneration are absent. Here, we found that Glutaredoxin3 (GLRX3) is an important redox-regulating molecule associated with NP cell senescence and disc degeneration. Using a hypoxic preconditioning method, we developed GLRX3+ mesenchymal stem cell-derived extracellular vehicles (EVs-GLRX3), which enhanced the cellular antioxidant defense, thus preventing reactive oxygen species (ROS) accumulation and senescence cascade expansion in vitro. Further, a disc tissue-like biopolymer-based supramolecular hydrogel, which was injectable, degradable, and ROS-responsive, was proposed to deliver EVs-GLRX3 for treating disc degeneration. Using a rat model of disc degeneration, we demonstrated that the EVs-GLRX3-loaded hydrogel attenuated mitochondrial damage, alleviated the NP senescence state, and restored ECM deposition by modulating the redox homeostasis. Our findings suggested that modulation of redox homeostasis in the disc can rejuvenate NP cell senescence and thus attenuate disc degeneration.

Comparative evaluation of four Chlorella species treating mariculture wastewater under different photoperiods: Nitrogen removal performance, enzyme activity, and antioxidant response.

The nitrogen removal performance, nitrogen metabolism enzyme activities, and antioxidant response of four Chlorella species (Chlorella sp., Chlorella vulgaris, Chlorella sorokiniana, and Chlorella protothecoides) were compared under different light: dark (L:D) photoperiods during treating mariculture wastewater. The increase of light duration in the range of 8L:16D to 16L:8D was beneficial to the chlorophyll synthesis of selected four Chlorella species. Chlorella vulgaris was the most effective to treat mariculture wastewater than Chlorella sp., Chlorella sorokiniana, and Chlorella protothecoides. and its microalgae density, photosynthetic activity, and nitrogen metabolism enzyme activity were higher than those of the other three Chlorella species. An obvious oxidative stress in microalgal cells was under 20L:4D photoperiod, which led to a decrease in photosynthetic activity and nitrogen metabolizing enzyme activity. Among the four Chlorella species, Chlorella protothecoides had the highest degree of light-induced stress and ROS accumulation. This study can provide suitable microalgae and optimal photoperiod for treating mariculture wastewater.

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.

Exosome-laden injectable self-healing hydrogel based on quaternized chitosan and oxidized starch attenuates disc degeneration by suppressing nucleus pulposus senescence.

Disc degeneration is the common pathology underlying various degenerative spinal disorders and currently there is no effective cure. Here, we found nucleus pulposus (NP) cell senescence was closely associated with the severity of disc degeneration, and exosomes (Exos) derived from mesenchymal stem cells (MSCs) ameliorated NP cell senescence and promoted extracellular matrix (ECM) deposition. As chitosan-based hydrogels have been widely used as vehicles to deliver Exos due to their prominent antibacterial capacity, biocompatibility, and biodegradability, we developed an Exos-laden hydrogel based on quaternized chitosan (QCS) and oxidized starch (OST) to treat disc degeneration. The synthesized QCS-OST hydrogel is injectable, self-healing, biocompatible, and demonstrated desirable pore size, injectable properties, and sustainable release of Exos. In a rat model of disc degeneration, the QCS-OST/Exos hydrogel was able to rejuvenate NP cell senescence, promote ECM remodeling, and partially restore the structures of NP and annulus fibrosis. Our findings suggested that the novel QCS-OST/Exos hydrogel is an effective therapeutic strategy for treating disc degeneration via alleviating NP cell senescence.

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.

A Janus Au-Polymersome Heterostructure with Near-Field Enhancement Effect for Implant-Associated Infection Phototherapy.

Polymer-inorganic hybrid Janus nanoparticles (PI-JNPs) have attracted extensive attention due to their special structures and functions. However, achieving the synergistic enhancement of photochemical activity between polymer and inorganic moieties in PI-JNPs remains challenging. Herein, the construction of a novel Janus Au-porphyrin polymersome (J-AuPPS) heterostructure by a facile one-step photocatalytic synthesis is reported. The near-field enhancement (NFE) effect between porphyrin polymersome (PPS) and Au nanoparticles in J-AuPPS is achieved to enhance its near-infrared (NIR) light absorption and electric/thermal field intensity at their interface, which improves the energy transfer and energetic charge-carrier generation. Therefore, J-AuPPS shows a higher NIR-activated photothermal conversion efficiency (48.4%) and generates more singlet oxygen compared with non-Janus core-particle Au-PPS nanostructure (28.4%). As a result, J-AuPPS exhibits excellent dual-mode (photothermal/photodynamic) antibacterial and anti-biofilm performance, thereby significantly enhancing the in vivo therapeutic effect in an implant-associated-infection rat model. This work is believed to motivate the rational design of advanced hybrid JNPs with desirable NFE effect and further extend their biological applications.

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.

Arbutin-modified microspheres prevent osteoarthritis progression by mobilizing local anti-inflammatory and antioxidant responses.

Osteoarthritis (OA) is a common degenerative joint disease worldwide and currently there is no effective strategy to stop its progression. It is known that oxidative stress and inflammation can promote the development of OA, and therapeutic strategies against these conditions may alleviate OA. Arbutin (ARB), a major ingredient of the Chinese medicinal herb cowberry leaf, exerts good antioxidant and anti-inflammatory activities yet has not been studied in OA. Here we developed ARB-loaded gelatine methacryloyl-Liposome (GM-Lipo@ARB) microspheres which showed long-term release of ARB and excellent cartilage-targeting effects. The ARB-loaded microspheres effectively reduced the inflammatory response in interleukin (IL)-1ß-treated arthritic chondrocytes. Moreover, the synthesized GM-Lipo@ARB microspheres regulated cartilage extracellular matrix (ECM) homeostasis through anti-inflammation effect via inhibiting NF-κB signaling and anti-oxidative stress effect via activating Nrf2 pathway. Intra-articular use of GM-Lipo@ARB can effectively reduce inflammation and oxidative stress in the articular cartilage and thus, attenuating OA progression in a mouse model. The study proposed a novel ARB-laden functional microsphere, GM-Lipo@ARB, and demonstrated that this compound may be used as an alternative therapeutics for treating OA.

Biomimetic Self-Assembling Metal-Organic Architectures with Non-Iridescent Structural Coloration for Synergetic Antibacterial and Osteogenic Activity of Implants.

Materials in nature feature versatile and programmable interactions to render macroscopic architectures with multiscale structural arrangements. By rationally combining metal-carboxylate and metal-organophosphate coordination interactions, Au25(MHA)18 (MHA, 6-mercaptohexanoic acid) nanocluster self-assembled structural color coating films and phytic acid (PA)-metal coordination complexes are sequentially constructed on the surface of titanium implants. The Lewis acid-base coordination principle applies for these metal-organic coordination networks. The isotropic arrangement of nanoclusters with a short-range order is investigated via grazing incidence wide-angle X-ray scattering. The integration of robust M-O (M = Ti, Zr, Hf) and labile Cu-O coordination bonds with high connectivity of Au25(MHA)18 nanoclusters enables these artificial photonic structures to achieve a combination of mechanical stability and bacteriostatic activity. Moreover, the colorless and transparent PA-metal complex layer allows the viewing of the structural color and surface wettability switching to hydrophilic and makes feasible the interfacial biomineralization of hydroxyapatite. Collectively, these modular metal-organic coordination-driven assemblies are predictive and rational material design strategies with tunable hierarchy and diversity. The complete metal-organic architectures will not only help improve the physicochemical properties of the bone-implant interface with synergistic antibacterial and osseointegration activities but also can boost surface engineering of medical metal implants.

A Combined Cyanine/Carbomer Gel Enhanced Photodynamic Antimicrobial Activity and Wound Healing.

As a non-invasive and non-specific therapeutic approach, photodynamic therapy (PDT) has been used to treat antibiotic-resistant bacteria with encouraging efficacy. Inspired by light, the photosensitizers can produce excessive reactive oxygen species (ROS) and, thus, effectively destroy or kill bacteria. Cyanine (Cy), a traditional photosensitizer for PDT, has the advantages of low cytotoxicity and high ROS yield. Yet, the water solubility and photostability for Cy are poor, which substantially limit its antibacterial efficiency and clinical translation. Herein, we combined Cy with carbomer gel (CBMG) to form a photodynamic Cy-CBMG hydrogel. In this system, Cy was evenly dispersed in CBMG, and CBMG significantly improved the water solubility and photostability of Cy via electrostatic interactions. The developed Cy-CBMG gel had less photodegradation under laser irradiation and thus can effectively elevate ROS accumulation in bacteria. The Cy-CBMG compound presented remarkable ROS-induced killing efficacy against methicillin-resistant Staphylococcus aureus (93.0%) and extended-spectrum ß-lactamase-producing Escherichia coli (88.7%) in vitro. Moreover, as a potential wound dressing material, the Cy-CBMG hydrogel exhibited excellent biocompatibility and effective antimicrobial ability to promote wound healing in vivo. Overall, this work proposed a practical strategy to synthesize a photosensitizer-excipient compound to enhance the photophysical property and antibacterial efficacy for PDT.

To Explore MR Imaging Radiomics for the Differentiation of Orbital Lymphoma and IgG4-Related Ophthalmic Disease.

Among orbital lymphoproliferative disorders, about 55% of diagnosed cancerous tumors are orbital lymphomas, and nearly 50% of benign cases are immunoglobulin G4-related ophthalmic disease (IgG4-ROD). However, due to nonspecific characteristics, the differentiation of the two diseases is challenging. In this study, conventional magnetic resonance imaging-based radiomics approaches were explored for clinical recognition of orbital lymphomas and IgG4-ROD. We investigated the value of radiomics features of axial T1- (T1WI-) and T2-weighted (T2WI), contrast-enhanced T1WI in axial (CE-T1WI) and coronal (CE-T1WI-cor) planes, and 78 patients (orbital lymphoma, 36; IgG4-ROD, 42) were retrospectively reviewed. The mass lesions were manually annotated and represented with 99 features. The performance of elastic net-based radiomics models using single or multiple modalities with or without feature selection was compared. The demographic features showed orbital lymphoma patients were significantly older than IgG4-ROD patients (p < 0.01), and most of the patients were male (72% in the orbital lymphoma group vs. 23% in the IgG4-ROD group; p = 0.03). The MR imaging findings revealed orbital lymphomas were mostly unilateral (81%, p = 0.02) and wrapped eyeballs or optic nerves frequently (78%, p = 0.02). In addition, orbital lymphomas showed isointense in T1WI (100%, p < 0.01), and IgG4-ROD was isointense (60%, p < 0.01) or hyperintense (40%, p < 0.01) in T1WI with well-defined shape (64%, p < 0.01). The experimental comparison indicated that using CE-T1WI radiomics features achieved superior results, and the features in combination with CE-T1WI-cor features and the feature preselection method could further improve the classification performance. In conclusion, this study comparatively analyzed orbital lymphoma and IgG4-ROD from demographic features, MR imaging findings, and radiomics features. It might deepen our understanding and benefit disease management.

Cancellous bone allograft is comparable to fibular strut allograft for augmentation in three- or four-part proximal humeral fractures.

BACKGROUND: Bone grafts have been used for augmentation and improving stability of reduced fractures in proximal humeral fractures. The aim of this study was to analyze the clinical and radiological outcomes after the use of cancellous bone allografts (CAs) for augmentation in 3- or 4-part proximal humeral fractures, and compare with fibular strut allografts (FAs). METHODS: Between November 2016 and February 2018, 55 patients, followed for at least 1 year, with 3- or 4-part proximal humeral fractures fixed with locking plates were included and grouped according to the type of allograft bone used for augmentation. In this retrospective analysis, we assessed and compared the clinical and radiological outcomes of the 2 groups, using the visual analog scale score, the Constant-Murley score (CMS), the disability of the arm, shoulder, and hand (DASH) score, the range of movement, neck-shaft angle (NSA), humeral head height (HHH), and the changes of NSA and HHH, as well as recording any complications. The repeatedly measured clinical and radiological outcomes were analyzed by linear mixed models. The differences in outcomes between groups at the final follow-up were compared using Student's t test. RESULTS: There were 28 patients in the CA group and 27 patients in the FA group with an average follow-up of 14.5 months. The mean age of all patients was 64 (36-86). Nonsignificant group effects were observed on CMS (ß = -8.792, P = .216), DASH (ß = 1.329, P = .094), NSA (ß = 1.432, P = .752), and HHH (ß = 1.660, P = .628). At the final follow-up, the patients in the CA group showed no significant differences in visual analog scale (1.8 vs. 2.2, P = .276), CMS (81.5 vs. 75.4, P = .072), and DASH (11.0 vs. 13.5, P = .235) scores compared with the FA group. There were no significant differences in the change of NSA (6 vs. 4, P = .387) or HHH (1 vs. 2, P = .261). CONCLUSIONS: Patients with 3- or 4-part proximal humeral fractures treated with locking plates combined with CAs have good clinical and radiographic outcomes, similar to those treated with FAs.

Development of novel denitrifying nitrite accumulation and phosphorus removal (DNAPR) process for offering an alternative pretreatment to achieve mainstream Anammox.

For achieving mainstream anaerobic ammonium oxidation (Anammox), there is a need to achieve organic carbon and phosphorus removal meanwhile supplying nitrite (NO2--N). Based on this demand, a novel anaerobic/anoxic/aerobic operated denitrifying nitrite accumulation and phosphorus removal (DNAPR) process was proposed for treating synthetic municipal and nitrate (NO3--N) wastewaters simultaneously (volume ratio of 5:1). By adjusting influent composition, discharging anaerobic-end supernatant, shortening anoxic duration, and adding a short aerobic stage, DNAPR process achieved promising and stable nitrate-to-nitrite transformation (78.35%) and phosphorus removal (98.34%) performance. Moreover, effluent with chemical oxygen demand of 16.63 mg/L, nitrite of 54.16 mg/L, orthophosphate of 0.37 mg/L, and nitrite to ammonia ratio of 1.3 were finally obtained after 141-day operation. Microbiological analysis showed that Thauera (34.9%) and unclassified_f_Rhodobacteraceae (6.79%) were both responsible for DNAPR. Therefore, DNAPR, serving as promising alternative pretreatment, might possess significance for achieving mainstream Anammox.

Comparison of nitrite accumulation performance and microbial community structure in endogenous partial denitrification process with acetate and glucose served as carbon source.

Although the combination of endogenous partial denitrification (EPD) and Anammox (EPD-AMX) were developed for deep-level nitrogen removal, the effects of different carbon source were not clear. In this study, the EPD performance was investigated comparatively with acetate (EPDA) and glucose (EPDG). Results revealed that through regulating chemical oxygen demand to phosphate ratio, Candidatus_Competibacter was highly enriched in EPDA (54.2%) and EPDG (51.3%), resulting high intracellular carbon storage efficiencies (90.2% and 85.3%, respectively). More stable nitrite accumulation was observed in EPDG than EPDA. But, higher specific nitrite generated rate (rNO2, 8.25 > 7.04 mgN·gVSS-1·h-1) and nitrate-to-nitrite transformation rate (NTR, 87.9% > 85.2%) were achieved in EPDA than those in EPDG. The functional bacterium was also shifted to Defluviicoccus in both EPDA (30.6%) and EPDG (25.8%). Moreover, with whether acetate or glucose, the EPD-AMX processes could achieve the same level of total nitrogen removal efficiencies (88.7% and 91.3%, respectively) via anammox mainly (87.8% and 89.4%, respectively).