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The wastewater discharge from the process of chrome plating, which contains 6:2 chlorinated polyfluorinated ether sulfonate (F-53B) and chromium (Cr), may be toxic to biofilm. In this study we found that the biofilm formed by Pseudomonas aeruginosa PAO1 was inhibited by exposure to a combination of F-53B and Cr(VI). The combined pollution damaged the cell membranes and the structure of the biofilm, and inhibited the production of the Pseudomonas quinolone-based signal, which affected biofilm formation. Moreover, the secretion of extracellular polymeric substances decreased as a result of this combined exposure. Exposure to F-53B and Cr(VI) individually or in combination could induce the excessive accumulation of intracellular reactive oxygen species (ROS), and the ROS positive rate of the bacteria increased under the treatment with 0.2 mmol/L of Cr(VI) and 250 nmol/L of F-53B, respectively. In addition, the activities of superoxide dismutase (SOD) and catalase (CAT) were enhanced for scavenging ROS in the bacteria that were exposed to Cr(VI) and F-53B. As an antioxidant, rutin was used to repair the toxicity of Cr(VI) and F-53B towards the biofilm formed by the bacteria. When rutin was added to the bacteria medium, with either Cr(VI) or F-53B as pollutant, or with the combined pollutants, the extracellular protein content of the bacteria recovered to 0.84, 0.94, and 0.85 times that of the control, respectively. Meanwhile, the accumulation of ROS and the activities of SOD and CAT decreased, which indicated that the addition of rutin can alleviate the oxidative stress and promote the antioxidant stress system.

General education is an important part of university education aiming at cultivating students’ comprehensive quality and sense of responsibility. As professional sports colleges and universities, higher sports colleges implement the curriculum reform of general education relatively late, and there is a problem of curriculum system construction in the process of implementing general education. The purpose of this paper is to research and discuss the application of general education management in higher education based on fuzzy cluster analysis in the Internet environment. This paper first discusses the teaching mode in the Internet environment and then analyzes the application of fuzzy cluster analysis in general education. Through fuzzy cluster analysis, the students’ understanding of general education before and after learning general education courses is compared, which paves the way for the promotion of general education in colleges and universities. Finally, this paper takes the general education curriculum system of higher physical education colleges as the research object and conducts fuzzy cluster analysis on it. The experimental results show that before studying general courses, 66.7% of the students hope to improve their language communication and expression skills, and 52.8% and 46% of the students hope to improve their practical ability and logical thinking ability. After receiving general education, only 23.5% of students have improved logical thinking ability, and only 13.7% of students have improved language communication and expression skills. The results show that general education does not meet the expectations of students, general education in higher physical education colleges is not effective, and the realization of general education needs to be further improved. To this end, schools can purchase network information resources, cooperate with well-known universities at home and abroad, develop general education courses with a global perspective, train students’ spirit of independent thinking, and master correct thinking methods.

Bacterial genetic material can be horizontally transferred between microorganisms via outer membrane vesicles (OMVs) released by bacteria. Up to now, the application of vesicle-mediated horizontal transfer of “degrading genes” in environmental remediation has not been reported. In this study, the nirS gene from an aerobic denitrification bacterium, Pseudomonas stutzeri, was enclosed in a pET28a plasmid, transformed into Escherichia coli (E. coli) DH5α and expressed in E. coli BL21. The E. coli DH5α released OMVs containing the recombination plasmid pET28a–nirS-EGFP. When compared with the free pET28a–nirS-EGFP plasmid’s inability to transform, nirS in OMVs could be transferred into E. coli BL21 with the transformation frequency of 2.76 × 106 CFU/g when the dosage of OMVs was 200 µg under natural conditions, and nirS could express successfully in recipient bacteria. Furthermore, the recipient bacteria that received OMVs containing pET28a–nirS-EGFP could produce 18.16 U/mL activity of nitrite reductase.

This study revealed a dual pathway for the degradation of tris (1-chloro-2-propanyl) phosphate (TCPP) by zero-valent iron (ZVI) and persulfate as co-milling agents in a mechanochemical (MC) process. Persulfate was activated with ZVI to degrade TCPP in a planetary ball mill. After milling for 2 h, 96.5% of the TCPP was degraded with the release of 63.16, 50.39 and 42.01% of the Cl−, SO42− and PO43−, respectively. In the first degradation pathway, persulfate was activated with ZVI to produce hydroxyl (·OH) radicals and ZVI is oxidized to Fe(Ⅱ) and Fe(Ⅲ). A substitution reaction occurred as a result of the attack of ·OH on the P–O–C bonds, leading to the successive breakage of the three P–O–C bonds in TCPP to produce PO43−. In the second pathway, a C–Cl bond in part of the TCPP molecule was oxidized by SO4·− to carbonyl and carboxyl groups. The P–O–C bonds continued to react with ·OH to produce PO43−. Finally, the intermediate organochloride products were further reductively dechlorinated by ZVI. However, the synergistic effect of the oxidation (·OH and SO4·−) and the reduction reaction (ZVI) did not completely degrade TCPP to CO2, resulting in a low mineralization rate (35.87%). Moreover, the intermediate products still showed the toxicities in LD50 and developmental toxicant. In addition, the method was applied for the degradation of TCPP in soil, and high degradations (>83.83%) were achieved in different types of soils.Speciality: Phosphorus flame retardants; Advanced oxidation process; Ball milling

The coexistence of per- and polyfluoroalkyl substances (PFASs) and heavy metals have been found in soils. However, the interaction between the combined pollutants in soils remains unclear. In this study, the adsorption processes of single and combined Cr(VI) and chlorinated polyfluoroalkyl ether potassium sulfonate (F-53 B) in red, yellow and black soils were simulated. When compared with the single F-53 B and Cr(VI), the adsorption amount of the combined F-53 B and Cr(VI) on soils changed with the types of soils. The interactions between F-53 B and Cr(VI) in soils affected their adsorption behavior. The adsorption of the combined F-53 B and Cr(VI) best fit second-order kinetics and the Freundlich equation. Moreover, aluminum and iron oxides are highly correlated with adsorption of F-53 B and Cr(VI). Both F-53 B and Cr(VI) can form complexes with aluminum and iron oxides through electrostatic interactions, but PFOS could be bridged with iron oxides to form an inner sphere complex and with aluminum oxides to form an outer sphere complex. The coexistence of F-53 B and Cr(VI) could change the fluorescent group of dissolved organic matter (DOM) in soils due to the complexation between F-53 B and DOM. In addition, F-53 B increased the acid-soluble portion of Cr and decreased its residual form, which promoted the environmental risk of Cr in soils.

In this study, a CotA laccase from Bacillus subtilis cjp3 was successfully immobilized onto magnetic graphene oxide (MGO) nanomaterials via covalent bonding with hydrochloride/N-hydroxysuccinimide (EDC/NHS). The morphology, structure, and properties of the MGO-laccase were then characterized by scanning-electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray-photoelectron spectroscopy (XPS), and a magnetic-property-measurement system (MPMS). The magnetic composite exhibited an extremely high binding capacity of ~145.04 mg/g and maintained maximal relative enzyme activities at 25 °C, pH 7, and a reaction time of 2 h. The pH, thermal, operational, and storage stabilities of MGO-laccase were significantly improved over those of free laccase. Moreover, MGO-laccase exhibited a higher tolerance than that of free laccase in the presence of organic solvents, inhibitors, metal ions, and salts. Furthermore, MGO-laccase showed good decolorization performance of malachite green (MG), with decolorization rates reaching 99% after 5 h of reaction at 30 °C and pH 6. In addition, the maximum saturation magnetization of MGO-laccase was 27.7 emu/g, allowing for rapid magnetic separation. Accordingly, magnetic separation allowed MGO-laccase to maintain 75% of its activity after ten consecutive decolorization cycles.

Layered double hydroxides (LDHs) are the promising minerals which can adsorb phosphates, moreover, phosphorus-containing LDHs can be used for fertilizers. In this study, we tested the ability of magnetic Fe3O4/Zn-Al-Fe-La -LDH to remove and recover phosphate from simulated sewage. Results demonstrated that a magnetic Fe3O4/Zn-Al-Fe-La-LDH dose of 1.2 g/l could achieve a maximum adsorption capacity of 169.5 mg/g under an initial phosphate concentration of 200 mg/L, an equilibrium contact time of 24 h and a pH of 4. The adsorption kinetics of phosphate onto the magnetic Fe3O4/Zn-Al-Fe-La-LDH were well governed by the pseudo-second-order kinetic model, and the adsorption data fit well to the Langmuir isotherms. After four adsorption-desorption cycles, the LDH still had an adsorption capacity of 31 mg/g, demonstrating its reusability. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis indicated that ion exchange occurred between phosphate and the interlayer anions, and that phosphate was inserted into the double structure of the adsorbent. ICP-OES analysis showed that the LDH was stable and did not release the metal ions into water. The phosphorus-adsorbed LDH (P-LDH) has the potential to be used as a slow-release fertilizer to increase the growth of the soybeans Glycine max. The absorption of the metal into the soybeans was also reduced, which proved that the application of this type of LDH is non-toxic to plants.

UV/sulfite systems with oxygen have recently been considered as advanced oxidation processes in view of the participation of oxysulfur radicals. However, the contribution of •OH and the efficiency of destructing emerging contaminants (ECs) in water remain largely unclear. Here, the UV/S(IV) process was applied with natural reoxygenation to degrade two typical ECs, diethyl phthalate (DEP) and bisphenol A (BPA) showing different properties. Solution pH played the key role in determining the reactive species, and both DEP and BPA were more favorably degraded at more alkaline conditions with higher utilization efficiency of SO32−. Specifically, the H•, O2•−, •OH and SO3•− were identified at acidic condition, but the amount of •OH accumulated significantly with the elevation of pH. Competitive quenching experiments showed that eaq− and •OH dominated the degradation of DEP and BPA at alkaline condition, respectively. Besides, DEP showed higher quantum efficiency for the indirect photolysis and mineralization degree than that of BPA at pH 9.2 mainly due to the direct use of the primary photoproduct. The possible transformation mechanisms of S(IV) and mineralization routes of both pollutants were proposed. This study may provide new insights into the mechanisms involved in UV/S(IV) process and a promising alternative for efficient removal of ECs in water.

The toxicities of sodium perfluorononyloxy-benzenesulfonate (OBS) to animals and plants are similar to those of perfluorooctane sulfonate. However, the mechanism of its toxicity to aerobic denitrifying bacteria is still unclear. In the present study, the ecotoxicity of OBS on an aerobic denitrifying strain, Pseudomonas stutzeri, was evaluated. The results showed that a dosage of OBS clearly affected the growth and aerobic denitrification of P. stutzeri. When compared with an unamended control, the degradation efficiency of the total nitrogen decreased by 30.13% during exposure to 200 mg/L of OBS, and the complete degradation time of nitrate-nitrogen was delayed by 4 h. The lactate dehydrogenase and superoxide dismutase produced by the bacteria increased with the concentration of OBS, and reactive oxygen species were also detected by confocal laser scanning microscope imaging. Transmission electron microscope imaging revealed chromosome deformation of the cells and damage to cell content; moreover, outer membrane vesicles were secreted from the bacteria, which was the important detoxification mechanism of P. stutzeri to OBS. Expression of the genes involved in aerobic nitrification and oxidative stress were also changed under OBS stress, which further confirmed the toxicity of OBS to P stutzeri. This study reveals the environmental exposure risk of OBS from the perspective of microorganisms.

The Fe2+/peroxymonosulfate (PMS) process always faced the major drawbacks of slow Fe2+ regeneration, reagent waste and strict pH requirement. Significant synergy was found by combining the visible light driven g-C3N4 photocatalysis with Fe2+(or Fe3+)/PMS at very low amount of reagent dosages. The synergistic mechanisms were investigated systematically. It was found that visible light played a minor role and the photoelectrons excited from g-C3N4 played the dominant role in the fast regeneration of Fe2+, and iron species should be the dominant activator for PMS compared with g-C3N4 in the combined process. For the complete degradation of 0.01 mM Bisphenol A (BPA), the consumption of PMS and Fe2+ in the combined process accounted for only 1/27 and 1/198 as that consumed in Fe2+/PMS process. The O2•–, 1O2 and Fe(IV) were found to be the dominant reactive species in Fe2+/PMS, while •OH was more preferably and continuously produced in the combined process. Moreover, the combined process showed significant advantages to maintain high efficiency over a wide pH range (3.0 ∼ 8.5) and to degrade pollutants with high concentrations. Stronger mineralization capability was also achieved by the combined process than the inclusive processes. Two degradation pathways of BPA degradation were proposed based on identifying the intermediates.

Quorum sensing signal molecules can be used to regulate the formation of biofilm, but it has not been reported that outer membrane vesicles (OMVs) can package and mediate signal molecules to regulate biofilm. We isolated and purified OMVs packaged with Pseudomonas quinolone signal (PQS) released by Pseudomonas aeruginosa and studied the effects of OMV-mediated PQS on the formation and structure of biofilms. OMV-mediated PQS promoted the growth of biofilm, and the cells in the biofilm were stretched, deformed and “bridged” with the surrounding cells. Raman spectrometry showed that the structure and components of the extracellular polymeric substances of P. aeruginosa changed; moreover extracellular proteins rather than polysaccharides played the dominant role in the formation of P. aeruginosa biofilms when regulated by OMV-mediated PQS. In the combination biofilm formed by P. aeruginosa and Staphylococcus aureus, the mediation of OMVs enhanced the inhibitory effect of PQS to the growth of S. aureus, resulting a decrease in EPS produced by the two bacteria. OMV-mediated PQS led to changes in the biodiversity, richness and structure of the microbial community in biofilms formed by active sludge. This work reveals the mechanism of OMVs mediated signal molecules regulating biofilm, which lays a new theoretical and practical foundation for guiding the operation of low-level of biofouling MBRs.

Perfluoroalkyl carboxylates (PFCAs) is toxic to the environment and human health. However, the degradation characteristics of fluorotelomer alcohols (FTOHs), precursors of PFACAs biodegradation, in the sludge during aerobic composting remain unclear. In this study, the degradation characteristics of 6:2 FTOH in sewage sludge by composting were researched and the influences of 6:2 FTOH on the composting process and microbial communities of the sludge were evaluated. After 52 days of composting, 6:2 FTOH retained only 0.73% of its original concentration, and its half-life was less than 1 d; 6:2 FTOH was degraded finally to perfluorohex unsaturated acid, perfluoropentanoic acid, 5:3 polyfluorinated acid (FTCA), 4:3 FTCA, and perfluorobutanoic acid through two pathways; and 6:2 FTCA and 6:2 fluorotel unsaturated acid were the intermediate products. Notably, dosing with 6:2 FTOH affected the composting process of sewage sludge. Additionally, 50 mg/kg 6:2 FTOH resulted in a decrease in the microbial richness and diversity of sludge compost. When compared with the compost without 6:2 FTOH, the proportion of Proteobacteria had increased, and the proportion of Firmicutes had decreased as the concentration of 6:2 FTOH increased. The negative effect of a dosage of 50 mg/kg 6:2 FTOH was more obvious than the effect of other treatments. This study expanded our understanding of the risk of sludge contaminated by 6:2 FTOH being used as a fertilizer after composting.

A vertical-flow constructed wetland (VFCW) was used to treat simulated domestic sewage containing perfluorooctane sulfonate (PFOS). The removal rate of PFOS in the domestic sewage was 93%–98%, through soil adsorption and plant uptake, suggesting that VFCWs can remove PFOS efficiently from wastewater. The removal of PFOS in the VFCW was dependent on soil adsorption and plant uptake; moreover, the percentage of soil adsorption was 61%–89%, and was higher than that of the plants uptake (5%–31%). The absorption capacity of Eichhornia crassipes (E. crassipes) (1186.71 mg/kg) was higher than that of Cyperus alternifolius (C. alternifolius) (162.77 mg/kg) under 10 mg/L PFOS, and the transfer factor of PFOS in E. crassipes and C. alternifolius was 0.04 and 0.58, respectively, indicating thatPFOS is noteasilytranslocatedto leaves fromroots of wetland plants; moreover, uptake of PFOS by E. crassipes was more than that of C. alternifolius because the biomass of E. crassipes was more than that of C. alternifolius and the roots of E. crassipes can take up PFOS directly from wastewater while C. alternifolius needs to do so via its roots in the soil. The concentration of 10 mg/L PFOS had an obvious inhibitory effect on the removal rate of total nitrogen, total phosphorus, chemical oxygen demand, and ammonia nitrogen in the VFCW, which decreased by 15%,10%,10% and 12%, respectively. Dosing with PFOS in the wastewater reduced the bacterial richness but increased the diversity in soil because PFOS stimulated the growth of PFOS-tolerant strains.

Taxol is a rare but extremely effective antitumor agent extracted from Taxus yew barks. Taxus plants are valuable and rare species, and the production of taxol from them is a complex process. Therefore, taxol-producing endophytic fungi seem to be a promising alternative because of their high practical value and convenient progress. In this study, the transcriptome of an endophytic fungus, Aspergillus aculeatinus Tax-6 was analyzed in order to understand the molecular mechanisms of producing fungal taxol. The results showed that genes involved in the mevalonate (MVA) pathway and non-mevalonate (MEP) pathway were expressed, including isopentenyl pyrophosphate transferase, geranyl pyrophosphate transferase, and geranylgeranyl pyrophosphate synthetase. However, those downstream genes involved in the conversion of taxa-4(5)-11(12)-diene from geranylgeranyl pyrophosphate were not expressed except for taxane 10-beta-hydroxylase. Additionally, a mutant strain, A. aculeatinus BT-2 was obtained from the original strain, A. aculeatinus Tax-6, using fungicidin as the mutagenic agent. The taxol yield of BT-2 was 560 µg L−1, which was higher than that of Tax-6. To identify the mechanism of the difference in taxol production, we compared the transcriptomes of the two fungi and explored the changes in the gene expression between them. When compared with the original strain, Tax-6, most genes related to the MVA pathway in the mutant strain BT-2 showed upregulation, including GGPPS. Moreover, most of the downstream genes were not expressed in the mutant fungi as well. Overall, the results revealed the pathway and mechanism of taxol synthesis in endophytic fungi and the potential for the construction of taxol-producing genetic engineering strains.

Per- and polyfluoroalkyl substances (PFASs) are toxic to microorganisms, thereby affecting microbial communities in sludge and soil, but how to repair the toxicity of microorganisms remains unclear. In this study, rutin, an antioxidant, was added into a culture medium with an aerobic denitrification bacteria, Pseudomonas stutzeri, under the exposure of sodium perfluorononyloxy-benzenesulfonate (OBS) to evaluate the repair mechanisms of rutin to the toxicity of OBS to the bacteria. The results showed that rutin could repair the damage of OBS to cell structures, and reduce the death rates of the bacteria under OBS exposure. The dosage of rutin reduced the effect on the inhibition of denitrification ability of P. stutzeri under OBS exposure. Compared with the bacteria exposed to single OBS, the dosage of rutin resulted in that the death rates recovered from 96.2% to 66.4%, the growth inhibition rate decreased from 46.5% to 15.8%, the total nitrogen removal rate recovered from 66.9% to 100%, and the NO2− content recovered from 34.5 mg/L to 0.22 mg/L. The expressions of key denitrification genes (napA, nirS, norB, nosZ) were recovered after adding rutin under OBS exposure. Rutin changed the positive rate of reactive oxygen species, the relative superoxide dismutase and catalase activities in the bacteria which exposed to OBS. The mechanism by which rutin repaired the toxicity of OBS to P. stutzeri related to inhibiting the activities of antioxidant and denitrification enzymes rather than affecting the expressions of genes involved in these enzymes. This study sheds light on the repair method of micro-organics and reveals the repair mechanisms under PFASs exposure.

Bioaccumulation and toxicity of per-and polyfluoroalkyl substances and metal in plants have been confirmed, however their contamination in soil and plants still requires extensive investigation. In this study the combined effects of chlorinated polyfluoroalkyl ether potassium sulfonate (F53B) and chromium (Cr) on water spinach (Ipomoea aquatica Forsk) were investigated. Compared with each single stress, the combination of F53B and Cr (VI) reduced the biomass and height and increasingly accumulated in the roots and destroyed the cell structure. Besides, the co-contamination led to the immobilization of F53B and Cr (VI) in soil, which affected their migration in soil and transfer to plants. The antioxidant response and photosynthesis of the plant weakened under the single Cr (VI) and enhanced under the single F53B treatment; however the contamination of F53B and Cr (VI) could also reduce this effect, as confirmed by the gene expression of MTa, psbA and psbcL genes. This study provides an evidence of the environmental risks resulting from the coexistence of F53B and Cr (VI).

In the process of using cross-linking method to immobilize enzymes, cross-linker have a certain negative effect on immobilization efficiency. In this study, a magnetic dialdehyde cellulose (MDAC) was prepared by oxidizing hydroxyl groups in cellulose to aldehyde groups. The modified cellulose could be used for the immobilization of bacterial laccase without cross-linker. The morphology and structure of the MDAC–laccase complex (MDAC-L) confirmed that the laccase was immobilized on MDAC via -CHO in MDAC and -NH2 in laccase. Under conditions of pH 4 and 45 °C, the maximum loading capacity of MDAC-L reached 210.74 mg/g, and relatively high enzyme activities maintained,. Compared with free laccase and immobilized laccase with glutaraldehyde, MDAC-L exhibited a wide pH range, temperature stability, reusability, and is suitable for long-term storage at low temperature. MDAC-L also improved the tolerance of free laccase to the presence of organic solvents, inhibitors and metal ions. Furthermore, the maximum saturation magnetization of MDAC-L was 34.07 emu/g, allowing for rapid magnetic separation. The relative activity of the immobilized laccase remained about 70% after 10 cycles of reuse. In addition, MDAC-L showed good decolorization performance when applied to crystal violet. Under the conditions of 45 °C and pH 6 for 21 h, the decolorization rate can reach about 90%. This study developed a novel cross-linking method for enzyme immobilization.

Per-and polyfluoroalkyl substances (PFASs) can be taken up and bioaccumulated in plants, but the toxic mechanisms of PFASs on wetland plants are still unclear. In present study, the toxic influences of perfluorooctane sulfonate (PFOS) on Eichhornia crassipes (E. crassipes) and Cyperus alternifolius (C. alternifolius) in a vertical-subsurface-flow constructed wetland were evaluated. The results showed that E. crassipes was more tolerant to PFOS stress than C. alternifolius, and the growth and chlorophyll synthesis of the two plants were promoted by low concentration (0.1 mg/L) of PFOS, and the chlorophyll synthesis was inhibited by high concentration (10 mg/L) of PFOS but the growth did not change obviously. The catalase activity and malondialdehyde content in the leaves of the two plants increased, peroxidase activity decreased under exposure to high concentrations of PFOS, and superoxide dismutase activity did not change. Under PFOS stress, the membrane of plant leaves and the cell structure of the two wetland plants were destroyed, and the mitochondrial contour of root cells became incomplete. Tanscriptomic analysis showed that the expression levels of genes related to cell wall formation, the cell apoptosis pathway, material synthesis, and metabolism in the plants were changed by PFOS. Analysis in fluorogenic quantitative real time polymerase chain reaction (RT-qPCR) also confirmed that the photosynthesis system of E. crassipes was inhibited, while that of C. alternifolius was promoted.

Bacterial genetic material can be horizontally transferred between microorganisms via outer membrane vesicles (OMVs) released by bacteria. Up to now, the application of vesicle-mediated horizontal transfer of “degrading genes” in environmental remediation has not been reported. In this study, thenirSgene from an aerobic denitrification bacterium,Pseudomonas stutzeri, was enclosed in a pET28a plasmid, transformed intoEscherichia coli(E. coli) DH5α and expressed inE. coliBL21. TheE. coliDH5α released OMVs containing the recombination plasmid pET28a–nirS. Moreover, the amount of released OMVs-protein and DNA in OMVs increase as heavy metal concentrations and temperature increased. When compared with the free pET28a–nirSplasmid’s inability to transform,nirSin OMVs could be transferred intoE. coliBL21 with the transformation frequency of 2.76×106CFU/g when the dosage of OMVs was 200 µg under natural conditions, andnirScould express successfully in recipient bacteria. Furthermore, the recipient bacteria that received OMVs could produce 18.16 U ml-1activity of nitrite reductase. Vesicle-mediated HGT of aerobic denitrification genes provides a novel bioaugmentation technology of nitrogen removal.ImportancePrevious studies have reported that bacterial genetic material can be horizontally transferred between microorganisms via outer membrane vesicles(OMVs) released by bacteria. However, the application of vesicle-mediated horizontal transfer of “degrading genes” in environmental remediation has not been reported. In this study, we found that OMVs could mediate horizontal transfer of pET28a–nirSplasmid between E. coli under natural condition. The transformation frequency reached to 2.76×106, which was higher than that of the free plasmid. Vesicle-mediated HGT of aerobic denitrification genes provides a novel bioaugmentation technology of nitrogen removal.

Development of efficient abatement technology for drugs and personal care products (PPCPs) has important scientific and practical significance to restrain its discharge to the natural water environment. This research aims to investigate ibuprofen (IBP) elimination in water film dielectric barrier discharge (DBD) plasma system driven by pulse power. With raising input power, the removal rate was improved. When input was 95 W, the removal rate and kinetic constant were up to 96.1% and 0.090 min−1, respectively. Besides, heightening frequency, duty ratio and solution flowrate would promote the degradation of IBP. IBP were more favorably degraded at lower IBP concentration and neutral pH condition. Active species including ·OH, electron, 1O2 and ·O2– dominated decomposition of IBP. The generation of O3, ·OH and H2O2 in deionized water and IBP solution was compared. UV–Vis spectrum and three dimensional fluorescence spectroscopy illustrated that IBP molecules could be decomposed effectively after DBD plasma treatment. During IBP degradation, COD and TOC was also relieved with extension of treatment time. The possible degradation routes of IBP in water film DBD plasma system were proposed based on LC-MS and Discrete Fourier transform (DFT) simulation. Based on the identified intermediates, their potential toxicity was evaluated with the help of US-EPA-TEST software. Water film DBD plasma technology was also suitable for actual wastewater treatment. The comparison of other technologies for IBP degradation was carried out finally. This work can provide exploratory platforms for comprehensively understanding and enhancing IBP degradation in DBD plasma technology.

Non-thermal plasma coupled with graphene-TiO2-Fe3O4 nanocomposites was applied to promote oxytetracycline (OTC) degradation in water. Graphene-TiO2-Fe3O4 nanocomposites were systematically characterized and calculated based on the density functional theory (DFT). Graphene-TiO2-Fe3O4 nanocomposites exhibited higher specific surface area, carrier separation rate and magnetic intensity. More importantly, graphene-TiO2-Fe3O4 nanocomposites were very prone to separation from solution. Compared to Fe3O4 and graphene-TiO2, graphene-TiO2-Fe3O4 nanocomposites further enhanced the removal efficiency of OTC. The highest removal efficiency could reach 98.1% when the doping amount of Fe3O4 was 20 wt%. The optimal parameters of catalyst dosage, peak voltage, air flow rate and pH value were 0.24 g/L, 18 kV, 4 L/min and 3.2, respectively. Compared with graphene-TiO2, the addition of graphene-TiO2-Fe3O4 nanocomposites decreased the concentration of O3 and H2O2, but increased the production of ·OH. ·OH, O3 and H2O2 played certain role for OTC elimination. The degradation process was explored by UV–Vis spectrum, three dimensional fluorescence, liquid chromatography-mass spectrometry (LC-MS), ion chromatography (IC) and discrete Fourier transform (DFT) analysis. Reactive molecular dynamical (MD) simulation was also performed to further investigate the reaction mechanisms, and the simulation show a good agreement with the experimental observation by analyzing the bond breaking and formation. The actual toxicity of OTC was alleviated after plasma-catalytic treatment.

Sulfamethoxazole (SMX) is a widely distributed emerging contaminant, which will bring serious harm to ecology and human health. Herein, evaluation of ozone (O3) coupled with calcium peroxide (CaO2) for SMX elimination was carried out. The results showed that CaO2 could promote SMX elimination in O3 system. The removal efficiency was improved from 65.6% to 73.9% when the CaO2 dosage was 0.06 g L−1. O3 dosage of 0.55 g h−1 was beneficial to SMX degradation. With decrease of initial SMX concentration, the removal of SMX firstly enhanced and then declined. Compared with alkaline, acidic and neutral conditions were favorable for SMX degradation. ROS including ·OH, ·O2− and 1O2 play critical role for SMX degradation. Synergetic effect could be established between O3 and CaO2, which encouraged formation of ·OH and accelerated SXM decomposition. The total organic carbon (TOC) and chemical oxygen demand (COD) were all declined after O3/CaO2 treatment. According to results of liquid chromatography-mass spectrometry (LC-MS) and references, four major pathways were proposed. The O3/CaO2 technology was also suitable for practical wastewater treatment. QSAR calculation and seed germination experiment showed that toxicity of the treatment solution was alleviated after O3/CaO2 treatment.

Wood-based plastics obtained via chemical modifications are usually dark and opaque, which limits their potential applications. All-wood plastics (AWPs) derived from ball-milled mulberry wood (BMMW) via an efficient heterogeneous esterification for 2 h in dimethyl sulfoxide (DMSO)/1-butyl-3-methylimidazolium chloride (BMIMCl) with the molar ratios of DMSO to BMIMCl at 5.9:1 exhibit a highly translucent appearance. With desirable thermoplasticity and tensile strength, AWPs can be processed into light-permeable specimens and transparent film. FT-IR and solid-state 13 C NMR spectra provide evidence for successful substitution of hydroxyl groups of BMMW by carboxybenzoyl groups. The darkness of AWPs arising from the oxidation of phenolic lignin into benzoquinone indicates that reaction time plays a critical role for controlling the transparency of AWPs. AWPs represent composite structures, including cellulose I and cellulose II. Different degradation mechanisms are observed among AWPs differently esterified. Moreover, the SEM and AFM images demonstrate the self-reinforcement of AWPs specimens and the heterogeneous surface of a transparent AWP film, respectively.

In this work, a novel bacterial strain exhibiting laccase activity was isolated from black liquor and identified as Bacillus subtilis cjp3. The CotA-laccase gene was cloned from strain cjp3 and expressed in Escherichia coli. The purified recombinant laccase has a maximum activity of 7320 U/L, maintaining high stabilities under a wide pH range and high temperature conditions. Nearly no loss of laccase activity was observed even at pH 9.0 after 10 h of incubation. Reactive blue 19, reactive black 5 and indigo carmine could be efficiently decolorized by the purified laccase in the presence of a mediator ABTS. More than 86% of tested dyes were removed in 4 h at pH = 9.0. The recombinant laccase can work well in a broad range of temperatures of 20-80°C(80% relative activity). These special properties indicated the potential use of the CotA-laccase in treating wastewater containing synthetic dyes.

In this work, active carbon nanofibers (ACFs) and reduced graphite oxidate (RGO) nanocomposites were facilely synthesized and proposed as capacitive deionization (CDI) electrodes for removal of different salty ions. According to this study, the dosage of ACFs has a great effect on the CDI performance of these electrode materials. Cyclic voltammetry results illustrated that sample RGO-ACF20 (RGO with 20 wt% ACFs) showed the best CDI performance among the all RGO-ACFx samples. The electro-adsorptive capacity of RGO-ACF20 electrode was 2.99 mg/g with electrical voltage of 2.0 V in about 20 min. Furthermore, the electrosorption of salty ions onto RGO-ACFx follows the Langmuir isotherm, implying the monolayer adsorption.

In this study, a lead-resistant bacterium, Bacillus subtilis X3, was used to prepare a lead bioadsorbent for immobilization and removal of lead in lead solution. The lead shot precipitate was analysed by scanning electron microscopy combined with energy dispersive X-ray fluorescence microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The adsorbed lead was mainly mineralized to form Pb 5 (PO 4 ) 3 OH, Pb 10 (PO 4 ) 6 (OH) 2 and Pb 5 (PO 4 ) 3 Cl; however, other mechanisms that can also promote the mineralization of lead should not be ignored. For example, Na + and Ca 2+ on the cell wall surface were exchanged with Pb 2+ in solution, which confirmed that the ion-exchange process occurred before mineralization. Moreover, adsorption bridging caused by extracellular polymeric substances also accelerated the further aggregation of lead, and the biomass was encapsulated by lead gradually. Hydroxyl, carbonyl, carboxyl and amine groups were not observed in lead mineral crystals, but the complexation between lead and these groups still benefited the mineralization of lead. The valence of Pb(II) was not changed after mineralization, which indicated that the biosorption process was not a redox reaction. Finally, biosorption occurred on the outer surface of the cell, but its specific surface area was relatively small, limiting the amount and efficiency of biosorption.

As a persistent organic pollutant listed in the Stockholm Convention, perfluorooctane sulfonate (PFOS) is extremely refractory to degradation under ambient conditions. Its potential ecotoxicity has aroused great concerns and research interests. However, little is known about the toxicity of PFOS on fungus. In this study, the white rot fungus Phanerochaete chrysosporium (P. chrysosporium) was adopted to assess the toxicity of PFOS in liquid culture. The addition of 100 mg/L PFOS potassium salt significantly decreased the fungal biomass by up to 76.4% comparing with un-amended control during the incubation period. The hyphostroma of P. chrysosporium was wizened and its cell membrane was thickened, while its vesicle structure was increased, based on the observation with scanning electron microscope (SEM) and transmission electron microscope (TEM). Nevertheless, the PFOS dosage of below 100 mg/L did not show a considerable damage to the growth of P. chrysosporium. The degradation of malachite green (MG) and 2,4-dichlorophenol (2,4-DCP) by P. chrysosporium was negatively affected by PFOS. At the initial dosage of 100 mg/L PFOS, the decolorization efficiency of MG and the degradation efficiency of 2,4-DCP decreased by 37% and 20%, respectively. This might be attributed to the inhibition of PFOS on MnP and LiP activities. The activities of MnP and LiP decreased by 20.6% and 43.4%, respectively. At a high dosage PFOS (100 mg/L), P. chrysosporium could show a high adsorption of MG but lose its pollutant degradation ability. Transcriptome analysis indicated that PFOS contamination could lead to the change of gene expression in the studied white rot fungus, and the genes regulating membrane structure, cell redox process, and cell transport, synthesis and metabolism were impacted. Membrane damage and oxidative damage were the two main mechanisms of PFOS’ toxicity to P. chrysosporium.

A superhydrophobic/superoleophilic material was prepared by coating hexadecyltrimethoxysilane-grafted reduced graphene oxide on the skeleton of a melamine sponge (HDTMS/rGO-MF) via a low-cost and simple method. The structure of HDTMS/rGO-MF was confirmed by scanning electron microscopy/energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. HDTMS/rGO-MF showed repellency to water and affinity to oil, with a water contact angle of 153.2° and oil contact angle of nearly 0°. Owing to its hierarchical pore structure and superhydrophobicity, the absorption capacities of HDTMS/rGO-MF for various oils and organic solvents were 8.79–20.85 g/g. Additionally, HDTMS/rGO-MF could be successfully reused through absorption-squeezing and absorption-distillation cycles, due to its chemical and mechanical stability. Thus, HDTMS/rGO-MF was used in an oil-collecting device with the assistance of a pump or a funnel, and achieved recovery rates of 50 %–90 % for various organic solvents. In particular, the recovery of chloroform reached 97 % after 10 cycles of filtration–separation. Moreover, HDTMS/rGO-MF increased the transparency of the n-hexane-in-water and toluene-in-water emulsion.

Graphene-based nanomaterials have attracted increasing attention in different areas, such as material science, chemical engineering and environmental science. In recent years, it and its derivatives (e.g. graphene oxide, reduced graphene oxide) have been considered promising functional materials in water pollution control because of their many unique properties. Recent intense research on the development of graphene-based composite materials has expanded their application to water treatment. Progress in the use of graphene, graphene oxide and graphene-based composite materials in water pollutant treatment is reviewed, including their use as adsorbents, photocatalysts, and the oxidant and oxidant (e.g. H2O2, peroxymonosulfate) activators in electrocatalysis. Water pollutants are heavy metal ions, dyestuffs, some inorganic nutrients and the emerging environmental pollutants. Not only are the mechanisms of the use of graphene and its derivatives in different treatment processes considered, but the effects of important factors on the removal efficiency of pollutants are analyzed, such as environmental factors (e.g. pH, pollutant concentration), the properties of the materials (e.g. particle size, surface charge) and the concentration and morphology of the material. Current problems of using graphene-based composite materials in water treatment are summarized and future research directions are proposed.

Environmental threats posed by perfluoroalkyl substances (PFASs) have received a great deal of attention in recent years. However, little is known about the influences of PFASs on microorganisms in the environment. In this study, several typical PFASs were selected, and their effects on bacterial communities were measured by Illumina MiSeq sequencing. The richness (Chao1 estimator), diversity (Shannon index) and community structure of the bacterial community changed after the exposure to PFASs (1 μg PFOS/g soil). The amendment of PFASs increased bacterial richness but decreased bacterial diversity, because PFASs stimulated the growth of some bacteria (e.g., Firmicutes, Acidobacteria and Actinobacteria) but inhibited other bacteria such as Latescibacteria and Chloroflexi. When low concentrations (0.01 μg/g and 0.1 μg/g) of perfluorooctane sulphonate (PFOS) were added, the promotion action was stronger than the toxic effect on soil bacteria. Conversely, the toxicity was stronger than the promotion action under high concentrations of PFOS (10 μg PFOS/g soil). PFASs pollution obviously disrupted the normal function of soil microorganisms. PFBS and PFHxS could activate sucrase and urease, while PFOS and 6:2FTS could inhibit these enzymes' activities. The reduction of soil functional genes also confirmed that PFOS, 6:2FTS and 6:2F53B inhibited soil enzyme activity and further destroyed the cellular structure, immune system and gene expression of soil bacteria. The effects of PFASs with long carbon chains on soil bacterial community and function was more obvious than that of short-chain PFASs.

The start-up efficiency of an anaerobic sequencing batch reactor (ASBR) fed with increasing methyl orange (MO) concentrations (from 25 mg l−1 to 500 mg l−1) were investigated in this study. The relationship between MO decolorization capacity and the microbial community structure was evaluated. More than 85% of COD and 75% of MO were removed during the whole operation period. However, little methane was generated, due to the successful competition of azo reduction over sulfate reduction and methanogenesis. The scanning electron microscopy and denaturing gradient gel electrophoresis analysis showed a significant variation of the microbial community composition with MO concentration increase. The thresholds of structural and functional disturbances were similar, suggesting a good correlation between degradation performance and community structure. Phylogenetic analysis indicated that Sulfuricurvum and Anaerolineaceae family were the most abundant microorganisms in ASBR responsible for MO decolorization. Batch experiments indicated that acclimated sludge could also use quinoide and Fe(III) as the electron acceptors, thus allowing an efficient reduction of azo dye.

Strain CICC 23870 capable of decolorization of various azo dyes under high saline conditions was isolated from saline-alkali soil. The oxygen-insensitive azoreductase in crude extracts exhibited a wide substrate adaptively in the presence of NADH as a cofactor. The decolorization process by free cells followed first-order kinetics, with a high Methyl Orange (MO) tolerance concentration up to 100 mg l(-1) estimated by Haldane model. The average decolorization rate of free cell system was 26.30 mg g(-1) h(-1) at initial MO concentration of 32.7 mg l(-1). However, the values for the systems of immobilized cells (4 mm) in alginate, alginate and nano-TiO2, and alginate and powered activated carbon (PAC) were 6.83, 4.64, and 11.34 mg g(-1) h(-1), respectively. The effective diffusion factors in the tree different matrices were calculated by diffusion-based mathematic model. The diffusion step controls the overall decolorization rate, and the effective diffusion coefficients varied with internal structure of the bead matrices. The diffusion coefficients were increased from 4.98 × 10(-9) to 2.25 × 10(-8) cm(2) s(-1) when PAC was added, but decreased to 6.62 × 10(-10) cm(2) s(-1) when nano-TiO2 was added. The immobilized matrices could be reused for at least three cycles but with a decreased decolorization rate, possibly due to the breakage of beads at the end of each cycle, which led to the loss of immobilized bacteria.

Lignin utilization during biomass conversion has been a major challenge for lignocellulosic biofuel. In particular, the conversion of lignin along with carbohydrate for fungible fuels and chemicals will both improve the overall carbon efficiency and reduce the need for chemical pretreatments. However, few biomass-converting microorganisms have the capacity to degrade all cell wall components including lignin, cellulose, and hemicellulose. We hereby evaluated a unique oleaginous fungus strain, Cunninghamella echinulata FR3, for its capacity to degrade lignin during biomass conversion to lipid, and the potential to carry out consolidated fermentation without chemical pretreatment, especially when combined with sorghum (Sorghum bicolor) bmr mutants with reduced lignin content. The study clearly showed that lignin was consumed together with carbohydrate during biomass conversion for all sorghum samples, which indicates that this organism has the potential for biomass conversion without chemical pretreatment. Even though dilute acid pretreatment of biomass resulted in more weight loss during fungal fermentation than untreated biomass, the lipid yields were comparable for untreated bmr6/bmr12 double mutant and dilute acid-pretreated wild-type biomass samples. The mechanisms for lignin degradation in oleaginous fungi were further elucidated through transcriptomics and chemical analysis. The studies showed that in C. echinulata FR3, the Fenton reaction may play an important role in lignin degradation. This discovery is among the first to show that a mechanism for lignin degradation similar to those found in white and brown rot basidiomycetous fungi exists in an oleaginous fungus. This study suggests that oleaginous fungi such as C. echinulata FR3 can be employed for complete biomass utilization in a consolidated platform without chemical pretreatment or can be used to convert lignin waste into lipids.

Biohydrogen production from the pulp and paper effluent containing rich lignocellulosic material could be achieved by the fermentation process. Xylose, an important hemicellulose hydrolysis product, is used less efficiently as a substrate for biohydrogen production. Moreover, azo dyes are usually added to fabricate anticounterfeiting paper, which further increases the complexity of wastewater. This study reports that xylose could serve as the sole carbon source for a pure culture of Klebsiella oxytoca GS-4-08 to achieve simultaneous decolorization and biohydrogen production. With 2 g liter −1 of xylose as the substrate, a maximum xylose utilization rate (UR xyl ) and a hydrogen molar yield (HMY) of 93.99% and 0.259 mol of H 2 mol of xylose −1 , respectively, were obtained. Biohydrogen kinetics and electron equivalent ( e − equiv) balance calculations indicated that methyl red (MR) penetrates and intracellularly inhibits both the pentose phosphate pathway and pyruvate fermentation pathway, while methyl orange (MO) acted independently of the glycolysis and biohydrogen pathway. The data demonstrate that biohydrogen pathways in the presence of azo dyes with sulfonate and carboxyl groups were different, but the azo dyes could be completely reduced during the biohydrogen production period in the presence of MO or MR. The feasibility of hydrogen production from industrial pulp and paper effluent by the strain if the xylose is sufficient was also proved and was not affected by toxic substances which usually exist in such wastewater, except for chlorophenol. This study offers a promising energy-recycling strategy for treating pulp and paper wastewaters, especially for those containing azo dyes. IMPORTANCE The pulp and paper industry is a major industry in many developing countries, and the global market of pulp and paper wastewater treatment is expected to increase by 60% between 2012 and 2020. Such wastewater contains large amounts of refractory contaminants, such as lignin, whose reclamation is considered economically crucial and environmentally friendly. Furthermore, azo dyes are usually added in order to fabricate anticounterfeiting paper, which further increases the complexity of the pulp and paper wastewater. This work may offer a better understanding of biohydrogen production from xylose in the presence of azo dyes and provide a promising energy-recycling method for treating pulp and paper wastewater, especially for those containing azo dyes.

Taxol is a curatively effective but rare anti-tumor agent extracted from Taxus (yew) barks; however, the high cost and low production of the extraction method have limited its widespread use. In this study, fungi isolated from Taxus chinensis var . mairei were tested for their ability to produce taxol. High performance liquid chromatography combined with mass spectrometry confirmed that Aspergillus aculeatinus Tax-6, one of the endophytic fungi, could produce taxol in potato dextrose agar liquid medium. NaOAc, Cu 2+ , and salicylic acid were introduced into the medium to enhance taxol production of strain Tax-6 because NaOAc is an important precursor of taxol, Cu 2+ may enhance the activity of oxidase and catalyze the formation of taxol, and salicylic acid could be an elicitor signal. Application of response surface methodology to optimize the culture led to the addition of CuSO 4 , salicylic acid and sodium acetate at 0.1 mg L −1 , 10 mg L −1 and 8 g L −1 to improve taxol yield from 334.92 to 1337.56 μg L −1 . Overall, the results of this study confirmed that fungal taxol has the potential to be broadly applied by optimizing the culture conditions.

In this study, a newly isolated oleaginous fungus, Mucor circinelloides ( M. circinelloides ) Q531, was able to convert mulberry branches into lipids. The highest yield and the maximum lipid content produced by the fungal cells were 42.43 ± 4.01 mg per gram dry substrate (gds) and 28.8 ± 2.85%, respectively. The main components of lignocellulosic biomass were gradually reduced during solid-state fermentation (SSF). Cellulose, hemicellulose and lignin were decreased from 45.11, 31.39 and 17.36% to 41.48, 28.71, and 15.1%, respectively. Gas chromatography analysis showed that the major compositions of the fermented products were palmitic acid (C16:0, 18.42%), palmitoleic acid (C16:1, 5.56%), stearic acid (C18:0, 5.87%), oleic acid (C18:1, 33.89%), linoleic acid (C18:2, 14.45%) and γ-linolenic acid (C18:3 n6, 22.53%) after 2 days of SSF. The fatty acid methyl esters contained unsaturated fatty acids with a ratio of 75.95%. The composition and content obtained in this study are more advantageous than those of many other biomass lipids. Meanwhile, the oleaginous fungus had a high cellulase activity of 1.39 ± 0.09 FPU gds −1 . The results indicate that the enzyme activity of the isolated fungus was capable of converting the cellulose and hemicelluloses to available sugar monomers which are beneficial for the production of lipids.