SPI1 involvement in malignant melanoma pathogenesis by regulation of HK2 through the AKT1/mTOR pathway.

Spi-1 proto-oncogene (SPI1) plays a vital role in carcinogenesis. Our work aimed to investigate the potential regulatory mechanism of SPI1 in melanoma. The mRNA and protein levels were measured via qRT-PCR and Western blotting. Cell viability was assessed by CCK-8 assay. The target relationship between SPI1 and hexokinase 2 (HK2) was determined using dual-luciferase reporter detection. ChIP was conducted to confirm the targeted relationship between SPI1 and the HK2 promoter. Immunohistochemistry analysis was conducted to measure the positive cell number of SPI1 and HK2 in melanoma tissues. The cell migration abilities were determined using a wound healing assay. Glucose consumption, pyruvate dehydrogenase activity, lactate production and ATP levels were measured to assess glycolysis. SPI1 transcription in melanoma cells and tissues was dramatically higher than that in adjacent normal tissues and epidermal melanocyte HEMa-LP, respectively. Knockdown of SPI1 restrained cell viability, metastasis and glycolysis in melanoma cells. SPI1 directly targeted HK2, and knockdown of SPI1 repressed HK2 expression. Overexpression of HK2 weakened the inhibitory effects of SPI1 knockdown on the viability, metastasis and glycolysis of melanoma cells. The serine-threonine kinase 1 (AKT1)/mammalian target of rapamycin (mTOR) axis is involved in melanoma progression. SPI1 knockdown restrained melanoma cell proliferation, metastasis and glycolysis by regulating the AKT1/mTOR pathway.

Role and mechanism of PIM family in the immune microenvironment of diffuse large B cell lymphoma.

BACKGROUND: Diffuse large B cell lymphoma (DLBCL) is a more common non-Hodgkin lymphoma (NHL). This study aims to explore the prognostic value of PIM kinase family in DLBCL and its relationship with the immune microenvironment, to provide a certain reference for the prognosis and treatment of DLBCL. METHODS: The prognostic value of PIM kinase family in DLBCL from the data set GSE10846 was verified through survival analysis and cox regression analysis. Mutations in PIM kinase family and its relationship with immune cell infiltration were explored with online cBioPortal, TIMER database, and single-gene GSEA analysis. Finally, the expression of PIM kinase family in tissues from DLBCL clinical samples was validated through immunohistochemical staining. RESULTS: The proteins of PIM kinase family were highly expressed in DLBCL patients, which are good prognostic factors for DLBCL patients. Then, PIM1-3 proteins were positively correlated with the immune infiltration of B cells, whose types of mutations also showed different degrees of correlation with B cells. PIM kinase family proteins also showed a high correlation with PDL1. In addition, PIM kinase family was also associated with the commonly mutated genes in DLBCL, such as MYD88, MYC, and BTK. CONCLUSION: PIM kinase family may be a potential therapeutic target for DLBCL patients.

Novel Nonradical Oxidation of Sulfonamide Antibiotics with Co(II)-Doped g-C3N4-Activated Peracetic Acid: Role of High-Valent Cobalt-Oxo Species.

Herein, we report that Co(II)-doped g-C3N4 can efficiently trigger peracetic acid (PAA) oxidation of various sulfonamides (SAs) in a wide pH range. Quite different from the traditional radical-generating or typical nonradical-involved (i.e., singlet oxygenation and mediated electron transfer) catalytic systems, the PAA activation follows a novel nonradical pathway with unprecedented high-valent cobalt-oxo species [Co(IV)] as the dominant reactive species. Our experiments and density functional theory calculations indicate that the Co atom fixated into the nitrogen pots of g-C3N4 serves as the main active site, enabling dissociation of the adsorbed PAA and conversion of the coordinated Co(II) to Co(IV) via a unique two-electron transfer mechanism. Considering Co(IV) to be highly electrophilic in nature, different substituents (i.e., five-membered and six-membered heterocyclic moieties) on the SAs could affect their nucleophilicity, thus leading to the differences in degradation efficiency and transformation pathway. Also, benefiting from the selective oxidation of Co(IV), the established oxidative system exhibits excellent anti-interference capacity and achieves satisfactory decontamination performance under actual water conditions. This study provides a new nonradical approach to degrade SAs by efficiently activating PAA via heterogeneous cobalt-complexed catalysts.

Integrating enhanced biological phosphorus removal in adsorption-stage to treat real domestic sewage.

Wastewater treatment innovation toward resource recovery facilities raises concerns about the adsorption and bio-degradation (A-B) process. This study integrated enhanced biological phosphorus removal (EBPR) into the A-stage for real domestic sewage treatment using the short sludge retention time (S-SRT) approach. The S-SRT approach resulted in outstanding phosphorus (over 90 %) and COD removal (approximately 88 %), increased sludge yield and organic matter content, and a 1.68-fold increase in energy recovery efficiency by sludge anaerobic digestion. The inhibition of nitrification relieved competition for carbon sources between denitrification and phosphorus removal, allowing for the enrichment of phosphorus-accumulating organisms (PAOs) such as Tetrasphaera and Halomonas, leading to enhanced phosphorus removal activities. Biological adsorption also plays a significant role in achieving steady phosphorus removal performance. This study demonstrates the potential of the S-SRT approach as an effective strategy for simultaneous carbon and phosphorus capture in the A-stage, contributing to energy and nutrient recovery from sewage.

Role and mechanism of LINC02390 and its potential target genes, CLECL1 and CD69, in immune microenvironment of lung adenocarcinoma.

BACKGROUND: Targeted therapy and immunotherapy has brought new hope to patients with lung adenocarcinoma (LUAD) with their applications. However, the prognosis of LUAD patients is still unpromising. OBJECTIVE: It is particularly important to find the biomarkers that can predict the prognosis of LUAD. In our previous study, we found that patients with high expression of LINC02390 had a better prognosis. The clinical significance of LINC02390 and its potential target genes, CLECL1 and CD69, in the prognosis of LUAD and its role in the immune microenvironment were explored. METHODS: Through the survival analysis, LINC02390 and its potential target genes, CLECL1 and CD69, were identified as good prognostic factors for LUAD. According to GO and KEGG analyses, LINC02390-related genes were identified potentially involved in immune-related signaling pathways. Gene mutations and their relationship with immune cell infiltration were verified through the online cbioportal and TIMER database. RESULTS: CD69 was found to positively associate with CD8 + T cells and CLECL1 was also positively associated with CD4 + T cells. A high expression of CD69 in CD8 + T cells was identified through the single-cell sequencing dataset GSE111894. Finally, CLECL1 and CD69 were lowly expressed in clinical tissue samples with LUAD by immunohistochemical staining. CONCLUSIONS: LINC02390 and its possible target genes, CLECL1 and CD69, may be potential targets for the immunotherapy in LUAD patients.

Identification of a cuproptosis-related lncRNA prognostic signature in lung adenocarcinoma.

PURPOSE: Cuproptosis-related long non-coding RNA (lncRNA) diseases are associated with the occurrence and development of tumors. This study aimed to investigate whether cuproptosis-related lncRNA can predict the prognosis of patients with lung adenocarcinoma (LUAD). METHODS: Cuproptosis-related lncRNA prognosis (CLPS) model was successfully constructed through cox regression and lasso regression analyses. Then, the prognostic value of CLPS model was tested through the survival analysis, the ROC curve and the nomogram. Finally, the correlation of CLPS model with tumor immunity and tumor mutation burden was analyzed, and the potential susceptibility of drugs for LUAD were predicted. RESULTS: CLPS model for LUAD (AC090948.1, CRIM1-DT, AC026356.2, AC004832.5, AL161431.1) was successfully constructed, which has an independent prognostic value. Furthermore, the risk score of CLPS model was correlated with tumor immune characteristics and immune escape, which can predict the sensitivity of drugs including Cisplatin, Etoposide, Gemcitabine, and Erlotinib. CONCLUSIONS: In conclusion, it was found that CLPS model was associated with tumor immunity and tumor mutation load, which also predicted four potentially sensitive drugs for LUAD patients at different risks.

Automatic control and optimal operation for greenhouse gas mitigation in sustainable wastewater treatment plants: A review.

In order to promote low-carbon sustainable operational management of the wastewater treatment plants (WWTPs), automatic control and optimal operation technologies, which devote to improving effluent quality, operational costs and greenhouse gas (GHG) emissions, have flourished in recent years. There is no consensus on the design procedure for optimal control/operation of sustainable WWTPs. In this review, we summarize recent researches on developing control and optimization strategies for GHG mitigation in WWTPs. Faced with the fact that direct carbon dioxide (CO2) emissions (considered biological origin) are generally not included in the carbon footprint of WWTPs, direct emissions (nitrous oxide (N2O), methane (CH4)) and indirect emissions are paid much attention. Firstly, the plant-wide models with GHG dynamic simulation, which are employed to design and evaluate the automatic control schemes as well as representative studies on identifying key factors affecting GHG emissions or comprehensive performance are outlined. Then, both traditional and advanced control methods commonly used in GHG mitigation are reviewed in detail, followed by the multi-objective optimization practices of control/operational parameters. Based on the mentioned control and (or) optimization strategies, a novel design framework for the optimal control/operation of sustainable WWTPs is proposed. The findings and design framework proposed in the paper will provide guidance for GHG mitigation and sustainable operation in WWTPs. It is foreseeable that more accurate and appropriate plant-wide models together with flexible control methods and intelligent optimization strategies will be developed to satisfy the upgrading requirements of WWTPs in the future.

Enhanced in-situ sludge reduction of the side-stream process via employing micro-aerobic approach in both mainstream and side-stream.

Side-stream reactor (SSR), as an in-situ sludge reduction process with high sludge reduction efficiency (SRE) and less negative impact on effluent, has been widely researched. In order to reduce cost and promote large-scale application, the anaerobic/anoxic/micro-aerobic/oxic bioreactor coupled with micro-aerobic SSR (AAMOM) was used to investigate nutrient removal and SRE under short hydraulic retention time (HRT) of SSR. When HRT of SSR was 4 h, AAMOM system achieved 30.41% SRE, while maintaining carbon and nitrogen removal efficiency. Micro-aerobic in mainstream accelerated the hydrolysis of particulate organic matter (POM) and promoted denitrification. Micro-aerobic in side-stream increased cell lysis and ATP dissipation, thus increasing SRE. Microbial community structure indicated that the cooperative interactions among hydrolytic, slow growing, predatory and fermentation bacteria played key roles in improving SRE. This study confirmed that SSR coupled micro-aerobic was a promising and practical process, which could benefit nitrogen removal and sludge reduction in municipal wastewater treatment plants.

CREB1 regulates KPNA2 by inhibiting mir-495-3p transcription to control melanoma progression : The role of the CREB1/miR-495-3p/KPNA2 axis in melanoma progression.

BACKGROUND: Melanoma is a common type of skin cancer, and its incidence is increasing gradually. Exploring melanoma pathogenesis helps to find new treatments. OBJECTIVE: We aimed to explore the potential molecular mechanisms by which CREB1 regulates melanoma. METHODS: TransmiR and ALGGEN were used to predict targets of CREB1 in the promoter of miR-495-3p or miR-495-3p and KPNA2, and a dual-luciferase reporter assay was performed to detect binding of CREB1 to these promoters. In addition, binding of CREB1 to the miR-495-3p promoter was confirmed by a ChIP assay. qRT‒PCR was carried out to detect mRNA levels of miR-495-3p, CREB1 and KPNA2. An EdU assay was conducted to detect cell viability. Transwell assays and flow cytometry were performed to assess cell migration and invasion and apoptosis, respectively. Moreover, factors associated with overall survival were analysed by using the Cox proportional hazards model. RESULTS: Our results show miR-495-3p to be significantly decreased in melanoma. Additionally, miR-495-3p overexpression inhibited melanoma cell viability. CREB1 targeted miR-495-3p, and CREB1 overexpression enhanced melanoma cell viability by inhibiting miR-495-3p transcription. Moreover, miR-495-3p targeted KPNA2, and CREB1 regulated KPNA2 by inhibiting miR-495-3p transcription to enhance melanoma cell viability. CONCLUSION: CREB1 regulates KPNA2 by inhibiting miR-495-3p transcription to control melanoma progression. Our results indicate the molecular mechanism by which the CREB1/miR-495-3p/KPNA2 axis regulates melanoma progression.

Dissecting the roles of conductive materials in attenuating antibiotic resistance genes: Evolution of physiological features and bacterial community.

Supplying conductive materials (CMs) into anaerobic bioreactors is considered as a promising technology for antibiotic wastewater treatment. However, whether and how CMs influence antibiotic resistance genes (ARGs) spread remains poorly known. Here, we investigated the effects of three CMs, i.e., magnetite, activated carbon (AC), and zero valent iron (ZVI), on ARGs dissemination during treating sulfamethoxazole wastewater, by dissecting the shifts of physiological features and microbial community. With the addition of magnetite, AC, and ZVI, the SMX removal was improved from 49.05 to 71.56-92.27 %, while the absolute abundance of ARGs reducing by 26.48 %, 61.95 %, 48.45 %, respectively. The reduced mobile genetic elements and antibiotic resistant bacteria suggested the inhibition of horizontal and vertical transfer of ARGs. The physiological features, including oxidative stress response, quorum sensing, and secretion system may regulate horizontal transfer of ARGs. The addition of all CMs relieved oxidative stress compared with no CMs, but ZVI may cause additional free radicals that needs to be concerned. Further, ZVI and AC also interfered with cell communication and secretion system. This research deepens the insights about the underlying mechanisms of CMs in regulating ARGs, and is expected to propose practical ways for mitigating ARGs proliferation.

The Feasibility of Maintaining Biological Phosphorus Removal in A-Stage via the Short Sludge Retention Time Approach: System Performance, Functional Genus Abundance, and Methanogenic Potential.

The increasing concerns on resource and energy recovery call for the modification of the current wastewater treatment strategy. This study synthetically evaluates the feasibility of the short sludge retention time approach to improve the energy recovery potential, but keeping steady biological phosphorus removal and system stability simultaneously. SBRS-SRT and SBRcontrol that simulated the short sludge retention time and conventional biological phosphorus removal processes, respectively, were set up to treat real domestic sewage for 120 d. SBRS-SRT achieved an efficient COD (91.5 ± 3.5%), PO43--P (95.4 ± 3.8%), and TP (93.5 ± 3.7%) removal and maintained the settling volume index around 50 mL/gSS when the sludge retention time was 3 d, indicating steady operational stability. The poor ammonia removal performance (15.7 ± 7.7%) and a few sequences detected in samples collected in SBRS-SRT indicated the washout of nitrifiers. The dominant phosphorus accumulating organisms Tetrasphaera and Hydrogenophaga, which were enriched with the shortened sludge retention time, was in line with the excellent phosphorus performance of SBRS-SRT. The calculated methanogenic efficiency of SBRS-SRT increased significantly, which was in line with the higher sludge yield. This study proved that the short sludge retention time is a promising and practical approach to integrate biological phosphorus removal in A-stage when re-engineering a biological nutrient removal process.

Insights into removal of sulfonamides in anaerobic activated sludge system: Mechanisms, degradation pathways and stress responses.

The fate of antibiotics in activated sludge has attracted increasing interests. However, the focus needs to shift from concerning removal efficiencies to understanding mechanisms and sludge responding to antibiotic toxicity. Herein, we operated two anaerobic sequencing batch reactors (ASBRs) for 200 days with sulfadiazine (SDZ) and sulfamethoxazole (SMX) added. The removal efficiency of SMX was higher than that of SDZ. SDZ was removed via adsorption (9.91-21.18%) and biodegradation (10.20-16.00%), while biodegradation (65.44-86.26%) was dominant for SMX removal. The mechanisms involved in adsorption and biodegradation were investigated, including adsorption strength, adsorption sites and the roles of enzymes. Protein-like substance (tryptophan) functioned vitally in adsorption by forming complexes with sulfonamides. P450 enzymes may catalyze sulfonamides degradation via hydroxylation and desulfurization. Activated sludge showed distinct responses to different sulfonamides, reflected in the changes of microbial communities and functions. These responses were related to sulfonamides removal, corresponding to the stronger adsorption capacity of activated sludge in ASBR-SDZ and degradation capacity in ASBR-SMX. Furthermore, the reasons for different removal efficiencies of sulfonamides were analyzed according to steric and electronic effects. These findings propose insights into antibiotic removal and broaden the knowledge for self-protection mechanisms of activated sludge under chronic toxicities of antibiotics.

Bio-CQDs surface modification BiOCl for the BPA elimination and evaluation in visible light: The contribution of C-localized level.

Carbon quantum dots (CQDs) doping semiconductors can boost solar-to-hydrogen conversion and the photodegradation in VIS-NIR light, therefore attract great attention, but the perspective of CQDs role is seldom explored. Here, a biomass-CQDs was assembled with BiOCl (CQDs/BiOCl), then served as the visible-photodegradation model for a mechanistic investigation. Furthermore, CQDs/BiOCl removed 90% bisphenol A (BPA) within 2 h under visible light. It was attributed to the C-localized state (CLS) produced by CQDs, which transfers forceless photo-electrons (e-) to generate holes (h+) in the CQDs/BiOCl valence band (VB) under visible light, the h+ mainly involved in the BPA degradation process. Then, the electrochemical experiments and theoretical calculations further proved that the efficiencies of charge separation (ηCS) and injection (ηCI) were proved by CQDs. Meanwhile, the possible BPA degradation pathways were accordingly proposed, and the ecotoxicity evaluation of the intermediates was also conducted by ECOSAR. The transformation pathways of BPA were divided into five orientations, and the toxicity of intermediates was decreased for Fish (LC50, ChV), Daphnid (LC50, ChV), Algae (EC50, ChV) except for P10 and P12. As the result, this study confirmed the feasibility of bio-CQDs/BiOCl preparation and it could be a photocatalyst to remove and detoxify BPA under visible light.

Multipath elimination of bisphenol A over bifunctional polymeric carbon nitride/biochar hybrids in the presence of persulfate and visible light.

Polymeric carbon nitride (PCN) has become a star material either in photocatalysis or in persulfate (PS) activation. In this work, we synthesized bifunctional biochar (BC)-doped PCN through a facile one-pot thermal treatment process. The PCN/BC hybrid (CNBC) with an optimized proportion could not only activate PS directly, but also possessed improved optical properties. Amorphous BC domains generated from the carbonization of external corncob provided attachments for the in-situ growth of PCN and upgraded its catalytic ability including electron transport property, visible light (VIS) utilization, and oxidation power. Mechanism studies demonstrated that in the CNBC/PS system without VIS, a nonradical electron transfer route was responsible for the degradation of bisphenol A (BPA), while in the CNBC/PS/VIS system, radical/nonradical mixing mechanisms including mediated electron transfer, radical oxidation, and hole oxidation were unveiled. Degradation pathways of BPA were deduced including direct oxidation at the aromatic ring, ß-scission of isopropyl, and ring cleavage. Most of the intermediates were less toxic than BPA as assessed by the ECOSAR software. The CNBC/PS/VIS system showed satisfactory resistance to environmental interferences except for HCO3-. This work provides a simple but effective strategy for the synthesis of PCN-based bifunctional catalysts and deepens mechanistic insights into hybrid advanced oxidation technologies.

Peroxymonosulfate activation by cobalt(II) for degradation of organic contaminants via high-valent cobalt-oxo and radical species.

The reaction between Co(II) and PMS is an appealing advanced oxidation process (AOP), where multiple reactive oxidizing species (ROS) including high-valent cobalt-oxo [Co(IV)], sulfate radical (SO4•-), and hydroxy radical (•OH) are intertwined together for degrading pollutants. However, the relative contribution of various ROS and the influences of nontarget matrix constituents, on the degradation process are still unclear and yet to be answered. In this study, we confirmed the generation Co(IV) as dominant intermediate oxidant at acid medium by using methyl phenyl sulfoxide (PMSO) as a probe compound. Using chemical scavenging methods, the role of SO4•- and •OH was also identified, and the major ROS were converted from Co(IV) to radical species with the increase of PMS/Co(II) molar ratio as well as pH value. In addition, we found that their contributions to the abatement of organic contaminants are highly dependent on both their available amount and substrate-specific reactivity. Generally, organic substrates with low ionization potential (IP) are prone to react with Co(IV). More interestingly, in contrast to radical-based oxidation, Co(IV) exhibited the great resistance to humic acid (HA) and background ions. This study might shed new light on the PMS activation by cobalt(II) for degradation of organic contaminants.

Insights into the oxidation of organic contaminants by Co(II) activated peracetic acid: The overlooked role of high-valent cobalt-oxo species.

The combination of Co(II) and peracetic acid (PAA) is a promising advanced oxidation process for the abatement of refractory organic contaminants, and acetylperoxy (CH3CO3•) and acetoxyl (CH3CO2•) radicals are generally recognized as the dominant and selective intermediate oxidants. However, the role of high-valent cobalt-oxo species [Co(IV)] have been overlooked. Herein, we confirmed that Co(II)/PAA reaction enables the generation of Co(IV) at acidic conditions based on multiple lines of evidences, including methyl phenyl sulfoxide (PMSO)-based probe experiments, 18O isotope-labeling technique, and in situ Raman spectroscopy. In-depth investigation reveals that the PAA oxidation mechanism is strongly pH dependent. The elevation of solution pH could induce major oxidants converting from Co(IV) to oxygen-centered radicals (i.e., CH3CO3• and CH3CO2•). The presence of H2O2 competitively consumes both Co(IV) and reactive radicals generated from Co(II)/PAA process, and thus, leading to an undesirably decline in catalytic performance. Additionally, as a highly reactive and selective oxidant, Co(IV) reacts readily with organic substances bearing electron-rich groups, and efficiently attenuating their biological toxicity. Our findings enrich the fundamental understanding of Co(II) and PAA reaction and will be useful for the application of Co(IV)-mediated processes.

Deciphering the transfers of antibiotic resistance genes under antibiotic exposure conditions: Driven by functional modules and bacterial community.

Antibiotics can exert selective pressures on sludge as well as affect the emergence and spread of antibiotic resistance genes (ARGs). However, the underlying mechanisms of ARGs transfers are still controversial and not fully understood in sludge system. In present study, two anaerobic sequence batch reactors (ASBR) were constructed to investigate the development of ARGs exposed to two sulfonamide antibiotics (SMs, sulfadiazine SDZ and sulfamethoxazole SMX) with increasing concentrations. The abundance of corresponding ARGs and total ARGs obviously increased with presence of SMs. Functional analyses indicated that oxidative stress response, signal transduction and type IV secretion systems were triggered by SMs, which would promote ARGs transfers. Network analysis revealed 18 genera were possible hosts of ARGs, and their abundances increased with SMs. Partial least-squares path modeling suggested functional modules directly influenced mobile genetic elements (MGEs) as well as the ARGs might be driven by both functional modules and bacteria community, while bacteria community composition played a more key role. Sludge with refractory antibiotics (SDZ) may stimulate the relevant functions and shift the microbial composition to a greater extent, causing more ARGs to emerge and spread. The mechanisms of ARGs transfers are revealed from the perspective of functional modules and bacterial community in sludge system for the first time, and it could provide beneficial directions, such as oxidative stress reduction, cellular communication control, bacterial composition directional regulation, for ARGs spread controlling in the future.

Activation of peroxymonosulfate by cobalt-impregnated biochar for atrazine degradation: The pivotal roles of persistent free radicals and ecotoxicity assessment.

Cobalt-mediated activation of peroxymonosulfate (PMS) has been extensively investigated for the degradation of emerging organic pollutants. In this study, PMS activation via cobalt-impregnated biochar towards atrazine (ATZ) degradation was systematically examined, and the underlying reaction mechanism was explicated. It was found that persistent free radicals (PFRs) contained in biochar play a pivotal role in PMS activation process. The PFRs enabled an efficient transfer electron to both cobalt atom and O2, facilitating the recycle of Co(III)/Co(II), and thereby leaded to an excellent catalytic performance. In contrast to oxic condition, the elimination of dissolved oxygen significantly retarded the ATZ degradation efficiency from 0.76 to 0.36 min-1. Radical scavenging experiments and electron paramagnetic resonance (EPR) analysis confirmed that the ATZ degradation was primarily due to SO4·- and, to a lesser extent, ·OH. In addition, dual descriptor (DD) method was carried out to reveal reactive sites on ATZ for radicals attacking and predicted derivatives. Meanwhile, the possible ATZ degradation pathways were accordingly proposed, and the ecotoxicity evaluation of the oxidation intermediates was also conducted by ECOSAR. Consequently, the cobalt-impregnated biochar could be an efficient and environmentally friendly catalyst to activate PMS for abatement and detoxication of ATZ.

Inhibition of biofouling in membrane bioreactor by metabolic uncoupler based on controlling microorganisms accumulation and quorum sensing signals secretion.

Biofouling is a limiting bottleneck in the development of membrane bioreactor (MBR) since the birth of this technology. Recently, the biofouling control strategy based on interfering with the bacterial quorum sensing (QS) system is highly desirable for biofouling control in MBR. In this study, three lab-scale parallel MBR systems were operated over 100 days to investigate the inhibitory effect of a metabolic uncoupler (3,3',4',5-tetrachlorosalicylanilide, TCS) on biofouling and the potential mechanism for biofouling control. Compared to the control MBR, the fouling cycle duration of MBR 2 with 100 µg/L TCS extended over two times. The attached biomass on membrane in MBR 2 decreased over 50% at the end of each operating period, which indicated that the addition of TCS significantly mitigated microorganisms accumulation on membrane. The content of interspecies QS signal (autoinducer-2) and intraspecific QS signals (N-octanoyl-dl-homoserine lactone, C8-HSL) was reduced by the TCS, suggesting the secretion of QS signals in MBR were affected by uncoupler. Although the addition of TCS induced brief fluctuations of extracellular proteins and polysaccharides, microorganisms seemed to rapidly acclimatize to the presence of TCS and then the secretion of extracellular polymeric substances (EPS) was inhibited by 100 µg/L TCS. The continuous operation of MBR was not be affected by the low-concentration uncoupler via the analysis of substrate removal and sludge growth. This study systematically evaluated the effect and inhibitory efficiency of TCS on biofouling, biomass accumulation, QS signals, EPS and treatment performances, demonstrating the feasibility of metabolic uncoupler for biofouling control in MBR.

Concentrating lactate-carbon flow on medium chain carboxylic acids production by hydrogen supply.

Upgrading lactate/carbohydrate-rich waste biomass into medium-chain carboxylic acids (MCCAs) by chain elongation (CE) technology exhibits economic and environmental benefits. However, the largely dispersive lactate-carbon-flow decreases MCCAs yield. This work discovered appropriate H2 supply could significantly reduce lactate-carbon-flow loss and improve MCCAs production (∼1.65 times) when the system is not operated according to well-defined operating conditions, and revealed corresponding mechanism. Hydrogen (H2) supply largely enhanced electron efficiency and electron transfer capacity, and H2 could reduce propionate (from competing acrylate pathway, which should be prevented, but when not possible, the carbon recovery from propionate is possible) to propanol, which was used as electron donor to elongate acetate and propionate. Moreover, H2 could react with CO2 (from CE process) to sequentially generate acetate and ethanol, which further contributed to caproate/caprylate generation. Comparing with non-H2-supplemented test, the lactate-carbon-flow used for MCCAs production was enhanced by ∼28.4% after H2 supply, and Clostridium spp. were the key discriminative microorganisms.