Luminescent Mechanism and Anti-Counterfeiting Application of Hydrophilic, Undoped Room-Temperature Phosphorescent Silicon Nanocrystals.

Silicon nanocrystals (SiNCs) have attracted extensive attention in many advanced applications due to silicon's high natural abundance, low toxicity, and impressive optical properties. However, these applications are mainly focused on fluorescent SiNCs, little attention is paid to SiNCs with room-temperature phosphorescence (RTP) and their relative applications, especially water-dispersed ones. Herein, this work presents water-dispersible RTP SiNCs (UA-SiNCs) and their optical applications. The UA-SiNCs with a uniform particle size of 2.8 nm are prepared by thermal hydrosilylation between hydrogen-terminated SiNCs (H-SiNCs) and 10-undecenoic acid (UA). Interestingly, the resultant UA-SiNCs can exhibit tunable long-lived RTP with an average lifetime of 0.85 s. The RTP feature of the UA-SiNCs is confirmed to the n-π* transitions of their surface C═O groups. Subsequently, new dual-modal emissive UA-SiNCs-based ink is fabricated by blending with sodium alginate (SA) as the binder. The customized anticounterfeiting labels are also prepared on cellulosic substrates by screen-printing technique. As expected, UA-SiNCs/SA ink exhibits excellent practicability in anticounterfeiting applications. These findings will trigger the rapid development of RTP SiNCs, envisioning enormous potential in future advanced applications such as high-level anti-counterfeiting, information encryption, and so forth.

Water-Soluble, Self-Healing, and Debonding Primer for the Interface between Silicone Leather and Polydimethylsiloxane Composites.

The exceptional hydrophobicity and antifouling properties of polydimethylsiloxane (PDMS) composites have attracted extensive interest as a result of low surface energy. However, PDMS composites are hardly bound by common primers, greatly limiting their practical applications. To address this issue, an EPMS/VTMS (EV) primer synthesized by hydrolytic polycondensation of 3-[(2,3)-epoxypropoxypropyl]methyldiethoxysilane (EPMS) and vinyltrimethoxysilane (VTMS) in acidic conditions is proposed. Interestingly, the EV primer exhibits exceptional reactivity, self-healing capabilities, and strong adhesion to various substrates, including metals, plastics, and glass. The bonding aluminum plates are easily debonded by immersion in water without any residue left. Subsequently, the EV primer has been applied to the interface between silicone leather and the PDMS composite. Results show that the bonding strength for the silicone leather coated with the EV/PDMS composite is 16 times higher than that of the silicone leather modified with the PDMS composite. Meanwhile, the modified silicone leather exhibits impressive antifouling performance, including aqueous and oily stains, appreciable breathability, and excellent wear resistance, even if suffering from 20 000 cycles of abrasion. These excellent advantages for the modified silicone leather should be attributable to the synergistic effect of the EV primer and the PDMS composite. These findings pave the way to develop an ecofriendly debonding primer for PDMS composites, greatly facilitating applications of silicone leather.

Magnetically Driven Cactus Spinelike Superhydrophobic Fe3O4 Vertical Array for High-Performance Fog Harvesting.

Cactus spinelike materials have attracted much attention due to high fog harvesting efficiency, but great challenges in structure fabrication and structural controllability still remain. In this study, we proposed a magnetically driven spray-coating method to fabricate a cactus spinelike superhydrophobic Fe3O4 vertical array on nonwoven cotton fabric. This method is simple and controllable; a mixture containing magnetic Fe3O4 particles and organosilicon resin was atomized into tiny droplets and arranged along the magnetic field lines. Different from the traditional method to prepare a cactus spinelike structure via liquid flow under magnet, which is usually accompanied with a big structure size and an unobvious structure feature due to the high viscosity of magnetic liquid. However, if the magnetic liquid is transformed into tiny magnetic droplets by a spraying method, it is promising to prepare micrometer-scale conical structures, and the reduction degree of bionic structures is high. When the fabricated structure is used for fog harvesting, it shows an extremely high efficiency of approximately 6.33 g cm-2 h-1, which is superior to most state-of-the-art fog harvesting materials. Considering the advantages of simplicity, structure controllability, and high fog harvesting rate, the reported strategy provides an avenue to build up high-performance fog harvesting materials.

Enhanced chlorobenzene removal by internal magnetic field through initial cell adhesion and biofilm formation.

Magnetic fields (MF) have been proven efficient in bioaugmentation, and the internal MFs have become competitive because they require no configuration, despite their application in waste gas treatment remaining largely unexplored. In this study, we firstly developed an intensity-regulable bioaugmentation with internal MF for gaseous chlorobenzene (CB) treatment with modified packing in batch bioreactors, and the elimination capacity increased by up to 26%, surpassing that of the external MF. Additionally, the microbial affinity to CB and the packing surface was enhanced, which was correlated with the ninefold increased secreted ratio of proteins/polysaccharides, 43% promoted cell surface hydrophobicity, and half reduced zeta potential. Furthermore, the dehydrogenase content was promoted over 3 times, and CB removal steadily increased with the rising intensity indicating enhanced biofilm activity and reduced CB bioimpedance; this was further supported by kinetic analysis, which resulted in improved cell adhesive ability and biological utilisation of CB. The results introduced a novel concept of adjustable magnetic bioaugmentation and provided technical support for industrial waste gas treatments. KEY POINTS: • Regulable magnetic bioaugmentation was developed to promote 26% chlorobenzene removal • Chlorobenzene mineralisation was enhanced under the magnetic field • Microbial adhesion was promoted through weakening repulsive forces.

Performance, kinetic characteristics and bacterial community of short-cut nitrification and denitrification system at different ferrous ion conditions.

In order to explore the operation performance, kinetic characteristics and bacterial community of the short-cut nitrification and denitrification (SND) system, the SND system with pre-cultured short cut nitrification and denitrification sludge was established and operated under different ferrous ion (Fe (II)) conditions. Experimental results showed that the average NH4+-N removal efficiency (ARE) of SND system was 97.3% on Day 5 and maintained a high level of 94.9% ± 1.3% for a long operation period. When the influent Fe(II) concentration increased from 2.3 to 7.3 mg L-1, the sedimentation performance, sludge concentration and organic matter removal performance were improved. However, higher Fe(II) of 12.3 mg L-1 decreased the removal of nitrogen and CODCr with the relative abundance (RA) of Proteobacteria and Bacteroidetes decreased to 30.28% and 19.41%, respectively. Proteobacteria, Bacteroidetes and Firmicutes were the dominant phyla in SND system. Higher Fe(II) level of 12.3 mg L-1 increase the RA of denitrifying genus Trichococcus (33.93%), and the denitrifying genus Thauera and Tolumonas dominant at Fe(II) level of no more than 7.3 mg L-1.

Enhancing lipid production and sedimentation of Chlorella pyrenoidosa in saline wastewater through the addition of agricultural phytohormones.

In this study, the effect of external agricultural phytohormones (mixed phytohormones) addition (1.0, 5.0, 10.0, and 20.0 mg L-1) on the growth performance, lipid productivity, and sedimentation efficiency of Chlorella pyrenoidosa cultivated in saline wastewater was investigated. Among the different concentrations evaluated, the highest biomass (1.00 g L-1) and lipid productivity (11.11 mg L-1 d-1) of microalgae were obtained at 10.0 mg L-1 agricultural phytohormones addition. Moreover, exogenous agricultural phytohormones also improved the sedimentation performance of C. pyrenoidosa, which was conducive to the harvest of microalgae resources, and the improvement of sedimentation performance was positively correlated with the amount of agricultural phytohormones used. The promotion of extracellular polymeric substances synthesis by phytohormones in microalgal cells could be considered as the reason for its promotion of microalgal sedimentation. Transcriptome analysis revealed that the addition of phytohormones upregulated the expression of genes related to the mitogen-activated protein kinase (MAPK)-mediated phytohormone signaling pathway and lipid synthesis, thereby improving salinity tolerance and lipid production in C. pyrenoidosa. Overall, agricultural phytohormones provide an effective and inexpensive strategy for increasing the lipid productivity and sedimentation efficiency of microalgae cultured in saline wastewater.

Enhancement of bio-S0 recovery and revealing the inhibitory effect on microorganisms under high sulfide loading.

Biodesulfurization is a mature technology, but obtaining biosulfur (S0) that can be easily settled naturally is still a challenge. Increasing the sulfide load is one of the known methods to obtain better settling of S0. However, the inhibitory effect of high levels of sulfide on microbes has also not been well studied. We constructed a high loading sulfide (1.55-10.86 kg S/m3/d) biological removal system. 100% sulfide removal and 0.56-2.53 kg S/m3/d S0 (7.0 ± 0.09-16.4 ± 0.25 µm) recovery were achieved at loads of 1.55-7.75 kg S/m3/d. Under the same load, S0 in the reflux sedimentation tank, which produced larger S0 particles (24.2 ± 0.73-53.8 ± 0.70 µm), increased the natural settling capacity and 45% recovery. For high level sulfide inhibitory effect, we used metagenomics and metatranscriptomics analyses. The increased sulfide load significantly inhibited the expression of flavin cytochrome c sulfide dehydrogenase subunit B (fccB) (Decreased from 615 ± 75 to 30 ± 5 TPM). At this time sulfide quinone reductase (SQR) (324 ± 185-1197 ± 51 TPM) was mainly responsible for sulfide oxidation and S0 production. When the sulfide load reached 2800 mg S/L, the SQR (730 ± 100 TPM) was also suppressed. This resulted in the accumulation of sulfide, causing suppression of carbon sequestration genes (Decreased from 3437 ± 842 to 665 ± 175 TPM). Other inhibitory effects included inhibition of microbial respiration, production of reactive oxygen species, and DNA damage. More sulfide-oxidizing bacteria (SOB) and newly identified potential SOB (99.1%) showed some activity (77.6%) upon sulfide accumulation. The main microorganisms in the sulfide accumulation environment were Thiomicrospiracea and Burkholderiaceae, whose sulfide oxidation capacity and respiration were not significantly inhibited. This study provides a new approach to enhance the natural sedimentation of S0 and describes new microbial mechanisms for the inhibitory effects of sulfide.

The fate of antibiotic resistance genes, microbial community, and potential pathogens in the maricultural sediment by live seaweeds and oxytetracycline.

Three common seaweeds including Ulva fasciata, Codium cylindricum and Ishige okamurai were used for the remediation of maricultural wastewater and sediment in the presence/absence of trace level of oxytetracycline (OTC) in lab-scale experiments. Higher NO3--N and PO43--P removal rates were achieved due to the presence of seaweeds, and trace OTC also had a positive effect on NO3--N removal. A slight variation of 2.10-2.15% were observed in the total relative abundances of antibiotic resistance genes (ARGs) of different sediment samples after one-month operation. However, the variation of ARGs profiles by the co-existence of different seaweeds and OTC was in the descending order of Ishige okamurai > Codium cylindricum > Ulva fasciata, which was in accordance with the variation of microbial hosts at genus level. The abundance of dominant tetracycline resistance genes promoted by the co-existence of different seaweeds and OTC in compared with the presence of single seaweed or OTC via metagenomic sequencing and qPCR analysis, and the co-existence of Ishige okamurai and OTC exhibited the largest impact. The potential pathogens were more sensitive to the co-existence of seaweed and OTC than single seaweeds. Meanwhile, a variety of ARGs were enriched in the pathogens, and the dominant pathogenic bacteria of Vibrio had 133 Vibrio species with 28 subtypes of ARGs. The variation of ARGs profiles in the sediment were strongly related with the dominant phyla Proteobacteria, Actinobacteria, Firmicutes, Planctomycetes and Cyanobacteria. Besides, Nitrate level exhibited more significant effect on ∑ARGs, ARGs resistant to vancomycin and streptogramin_a, while phosphate level exhibited more positively significant effect on ARGs resistant to fosmidomycin, ATFBT and cephalosporin.

Airlift two-phase partitioning bioreactor for dichloromethane removal: Silicone rubber stimulated biodegradation and its auto-circulation.

Solid non-aqueous phases (NAPs), such as silicone rubber, have been used extensively to improve the removal of volatile organic compounds (VOCs). However, the removal of VOCs is difficult to be further improved because the poor understanding of the mass transfer and reaction processes. Further, the conventional reactors were either complicated or uneconomical. In view of this, herein, an airlift bioreactor with silicone rubber was designed and investigated for dichloromethane (DCM) treatment. The removal efficiency of Reactor 1 (with silicone rubber) was significantly higher than that of Reactor 2 (without silicone rubber), with corresponding higher chloride ion and CO2 production. It was found that Reactor 1 achieved a much better DCM shock tolerance capability and biomass stability than Reactor 2. Silicone rubber not only enhanced the mass transfer in terms of both gas/liquid and gas/microbial phases, but also decreased the toxicity of DCM to microorganisms. Noteworthily, despite the identical inoculum used, the relative abundance of potential DCM-degrading bacteria in Reactor 1 (91.2%) was much higher than that in Reactor 2 (24.3%) at 216 h. Additionally, the silicone rubber could be automatically circulated in the airlift bioreactor due to the driven effect of the airflow, resulting in a significant reduction of energy consumption.

Mechanisms of Active Substances in a Dielectric Barrier Discharge Reactor: Species Determination, Interaction Analysis, and Contribution to Chlorobenzene Removal.

Several typical active substances (•NO, •NO2, H2O2, O3, •OH, and O2-•), directly or indirectly play dominant roles during dielectric barrier discharge (DBD) reaction. This study measured these active substances and removed them by using radical scavengers, such as catalase, superoxide dismutase, carboxy-PTIO (c-PTIO), tert-butanol (TBA), and MnO2 in different reaction atmospheres (air, N2, and O2). The mechanism for chlorobenzene (CB) removal by plasma in air atmosphere was also investigated. The production of O═NOO-• generated by •NO took around 75% of the total production of O═NOO-•. Removing •NO increased the O3 amount by about 80% likely because of the mutual inhibition between O3 and reactive nitrogen species in or out of the discharge area. The quantitative comparison of •OH and H2O2 revealed that the formation of •OH was 3.06-4.65 times that of H2O2 in these reaction atmospheres. Calculation results showed that approximately 1.61% of H2O was used for O3 generation. Ionization patterns affected the form of solid deposits during the removal of CB in N2 and O2 atmospheres caused by Penning ionization and thermal radiation tendencies, respectively. Correlation analysis results suggested the macroscopic synergistic or inhibitory effects happened among these active substances. A zero-dimensional reaction kinetics model was adopted to analyze the reactions during the formation of active substances in DBD, and the results showed good consistency with experiments. The interactions of each active substance were clarified. Finally, a response surface method model was developed to predict CB removal by the DBD plasma process. Stepwise regression analysis results showed that CB removal was affected by the contents of different active substances in air, N2 atmosphere, and O2 atmosphere, respectively: O2-•, •OH, and O3; H2O2, O═NOO-•, and O3; •OH and O3.

Migration, Distribution, and Safety Evaluation of Specific Phenotypic and Functional Mouse Spleen-Derived Invariant Natural Killer T2 Cells after Adoptive Infusion.

Herein, the migration distribution and safety of specific phenotypic and functionally identified spleen-derived invariant natural killer T2 (iNKT2) cells after adoptive infusion in mice were studied. The proliferation and differentiation of iNKT cells were induced by intraperitoneal injection of α-galactosylceramide (α-GalCer) in vivo. Mouse spleens were isolated in a sterile environment. iNKT cells were isolated by magnetic-activated cell sorting columns (MS columns). Cytometric bead array (CBA) assay was used to detect cytokine secretion in the supernatant stimulated by iNKT cells. The basic life status of the mice was observed, and systematic quantitative scoring was conducted after injecting spleen-derived iNKT cells through the tail vein. An in vivo imaging system was used to trace the migration and distribution of iNKT cells in DBA mice. The percentage of the iNKT2 subgroup was the highest in 3 days after intraperitoneal injection of α-GalCer, and iNKT2 subsets accounted for more than 92% after separation and purification by magnetic-activated cell sorting (MACS). Anti-inflammatory cytokine IL-4 was mainly found in the supernatant of cell cultures. The adoptive infusion of iNKT cells into healthy mice resulted in no significant change in the basic life status of mice compared with the noninjected group. iNKT cells were detected in the lung, spleen, and liver, but no fluorescence was detected in lymph nodes and thymus. After dissecting the mice, it was found that there were no significant abnormalities in the relevant immune organs, brain, heart, kidney, lung, and other organs. Intraperitoneal injection of α-GalCer results in a large number of iNKT2 cells, mainly secreting anti-inflammatory cytokine IL-4, from the spleen of mice. After adoptive infusion, the iNKT2 cells mainly settled in the liver and spleen of mice with a satisfactory safety profile.

Optimization of photocatalytic degradation conditions and toxicity assessment of norfloxacin under visible light by new lamellar structure magnetic ZnO/g-C3N4.

Degradation of norfloxacin (NFX) by zinc oxide (ZnO)/g-C3N4, a magnetic sheet ZnO with g-C3N4 on its surface was studied. Through a new preparation system method, hydrothermal reaction provides a solid-layered magnetic ZnO material basis, and the simple thermal condensation method was used to transform the urea into g-C3N4 on the magnetic sheet ZnO in a uniform and orderly manner to increase the stability and photocatalytic performance of the material. Compared with previous studies, the pore volume and photocatalytic performance of the material are improved, and became more stable. By studying the degradation effect of basic and photocatalytic materials prepared in different proportions, the kinetic constant of ZGF is 0.01446 (min-1). The response surface methodology (RSM) was used to study the optimization and effect of solution pH (4-12), photocatalyst concentration (0.2-1.8 g/L), and NFX concentration (3-15 mg/L) on the degradation rate of NFX during photocatalytic degradation. The R2 value of the RSM model was 0.9656. The NFX removal rate is higher than 90% when the amount of catalyst is 1.43 g/L, the solution pH is 7.12, and the NFX concentration is less than 8.61 mg/L. After 5 cycles, the degradation rate of magnetic materials decreased to 92.8% of the first time. The capture experiment showed that the photocatalytic machine Toxicities was mainly hole action. The TOC removal rate within 2 h was 30%, a special intermediate toxicity analysis method was adopted according to the characteristics of NFX's inhibitory effect on Escherichia coli community. The toxicity of degraded NFX solution disappeared, and the possibility of non-toxic harm of by-products was verified. LC-Q-TOF method was used to detect and analyze various intermediate products converted from NFX after photocatalytic degradation, and the photocatalytic degradation pathway of NFX was proposed.

Methylation of H3K27 and H3K4 in key gene promoter regions of thymus in RA mice is involved in the abnormal development and differentiation of iNKT cells.

Epigenetic modifications have been shown to be important for immune cell differentiation by regulating gene transcription. However, the role and mechanism of histone methylation in the development and differentiation of iNKT cells in rheumatoid arthritis (RA) mice have yet to be deciphered. The DBA/1 mouse RA model was established by using a modified GPI mixed peptide. We demonstrated that total peripheral blood, thymus, and spleen iNKT cells in RA mice decreased significantly, while iNKT1 in the thymus and spleen was increased significantly. PLZF protein and PLZF mRNA levels were significantly decreased in thymus DP T cells, while T-bet protein and mRNA were significantly increased in thymus iNKT cells. We found a marked accumulation in H3K27me3 around the promoter regions of the signature gene Zbtb16 in RA mice thymus DP T cells, and an accumulation of H3K4me3 around the promoters of the Tbx21 gene in iNKT cells. The expression levels of UTX in the thymus of RA mice were significantly reduced. The changes in the above indicators were particularly significant in the progressive phase of inflammation (11 days after modeling) and the peak phase of inflammation (14 days after modeling) in RA mice. Developmental and differentiation defects of iNKT cells in RA mice were associated with abnormal methylation levels (H3K27me3 and H3K4me3) in the promoters of key genes Zbtb16 (encoding PLZF) and Tbx21 (encoding T-bet). Decreased UTX of thymus histone demethylase levels resulted in the accumulation of H3K27me3 modification.

Effect of cold plasma on maintaining the quality of chub mackerel (Scomber japonicus): biochemical and sensory attributes.

BACKGROUND: Atmospheric cold plasma (ACP) has emerged as a potential alternative to traditional methods for non-thermal food decontamination. However, few data are available about ACP treatment for seafood. In this study, dielectric barrier discharge (DBD) was applied to generate CP, and the aim of the study was to investigate the effectiveness of DBD-ACP on improving the quality of chub mackerel on the basis of chemical, microbial and sensory characteristics. RESULTS: The effect of DBD-ACP on the quality of chub mackerel (Scomber japonicus) during storage was examined. Results revealed that the optimal voltage level and exposure time of this treatment were 60 kV and 60 s respectively, and such conditions exhibited excellent inactivation efficacy and weak influence on proximate chemical compositions. Variations in total viable count (TVC), sensory scores and total volatile basic nitrogen (TVB-N) indicated that ACP treatment extended the shelf life of chub mackerel to 14 days, whereas samples without this treatment exceeded the limits of the three parameters after 6 days. The slow development rates of peroxide value (PV) and thiobarbituric acid (TBA) value implied that lipid oxidation was also effectively retarded by ACP exposure. Scanning electron microscopy confirmed that CP could effectively delay the degradation of myofibrillar proteins and enhance the stability of tissue structures. CONCLUSION: The excellent antimicrobial efficacy of ACP treatment makes it a potential and promising alternative to other seafood preservation technology. This is the first report on the application of ACP to seafood, which is essential to perishable food storage. © 2018 Society of Chemical Industry.

Piscinibacter caeni sp. nov., isolated from activated sludge.

A yellowish-pigmented bacterial strain, designated as MQ-18T, was isolated from a sample of activated sludge collected from a pharmaceutical factory in Zhejiang, China. The strain was characterized through a polyphasic taxonomy approach. 16S rRNA gene sequence analysis demonstrated that strain MQ-18T showed high similarities to Piscinibacter defluvii SH-1T (99.7 %) and Piscinibacter aquaticus IMCC1728T (98.4 %), thereby suggesting that it belongs to the genus Piscinibacter. The DNA-DNA relatedness values of this strain to strains SH-1T and IMCC1728T were only 35.4 and 33.3 %, respectively. Cells of MQ-18T were Gram-negative, aerobic, motile, rod-shaped and non-spore forming. This strain exhibited growth at 25-37 °C (optimum: 30 °C) in the presence of 0-3.0 % (w/v) NaCl (optimum, 0 % NaCl) and at pH 5.0-8.0 (pH 7.0). The predominant fatty acids were C12 : 0 (5.5 %), C16 : 0 (33.7 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 38.5 %), and summed feature 4 (anteiso-C17 : 1 B and/or iso C17 : 1 I; 11.6 %). The main quinone type was ubiquinone-8, and the major polyamines were cadaverine and putrescine. The major polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content was 70.1 mol%. On the basis of its phylogenetic, phenotypic and physiological characteristics, strain MQ-18T is considered to represent a novel species of the genus Piscinibacter, for which the name Piscinibacter caeni sp. nov. is proposed. The type strain is MQ-18T (CCTCC AB 2017223T=JCM 32138T).

Comparative investigation on a hexane-degrading strain with different cell surface hydrophobicities mediated by starch and chitosan.

Bioremediation usually exhibits low removal efficiency toward hexane because of poor water solubility, which limits the mass transfer rate between the substrate and microorganism. This work aimed to enhance the hexane degradation rate by increasing cell surface hydrophobicity (CSH) of the degrader, Pseudomonas mendocina NX-1. The CSH of P. mendocina NX-1 was manipulated by treatment with starch and chitosan solution of varied concentrations, reaching a maximum hydrophobicity of 52%. The biodegradation of hexane conformed to the Haldane inhibition model, and the maximum degradation rate (ν max) of the cells with 52% CSH was 0.72 mg (mg cell)-1·h-1 in comparison with 0.47 mg (mg cell)-1·h-1 for cells with 15% CSH. The production of CO2 by high CSH cells was threefold higher than that by cells at 15% CSH within 30 h, and the cumulative rates of O2 consumption were 0.16 and 0.05 mL/h, respectively. High CSH was related to low negative charge carried by the cell surface and probably reduced the repulsive electrostatic interactions between hexane and microorganisms. The FT-IR spectra of cell envelopes demonstrated that the methyl chain was inversely proportional to increasing CSH values, but proteins exhibited a positive effect to CSH enhancement. The ratio of extracellular proteins and polysaccharides increased from 0.87 to 3.78 when the cells were treated with starch and chitosan, indicating their possible roles in increased CSH.

Characterization and Genome Analysis of a Nicotine and Nicotinic Acid-Degrading Strain Pseudomonas putida JQ581 Isolated from Marine.

The presence of nicotine and nicotinic acid (NA) in the marine environment has caused great harm to human health and the natural environment. Therefore, there is an urgent need to use efficient and economical methods to remove such pollutants from the environment. In this study, a nicotine and NA-degrading bacterium-strain JQ581-was isolated from sediment from the East China Sea and identified as a member of Pseudomonas putida based on morphology, physio-biochemical characteristics, and 16S rDNA gene analysis. The relationship between growth and nicotine/NA degradation suggested that strain JQ581 was a good candidate for applications in the bioaugmentation treatment of nicotine/NA contamination. The degradation intermediates of nicotine are pseudooxynicotine (PN) and 3-succinoyl-pyridine (SP) based on UV, high performance liquid chromatography, and liquid chromatography-mass spectrometry analyses. However, 6-hydroxy-3-succinoyl-pyridine (HSP) was not detected. NA degradation intermediates were identified as 6-hydroxynicotinic acid (6HNA). The whole genome of strain JQ581 was sequenced and analyzed. Genome sequence analysis revealed that strain JQ581 contained the gene clusters for nicotine and NA degradation. This is the first report where a marine-derived Pseudomonas strain had the ability to degrade nicotine and NA simultaneously.

Degradation of ethyl mercaptan and its major intermediate diethyl disulfide by Pseudomonas sp. strain WL2.

A Pseudomonas sp. strain WL2 that is able to efficiently metabolize ethyl mercaptan (EM) into diethyl disulfide (DEDS) through enzymatic oxidation was isolated from the activated sludge of a pharmaceutical wastewater plant. One hundred percent removal of 113.5 mg L(-1) EM and 110.3 mg L(-1) DEDS were obtained within 14 and 32 h, respectively. A putative EM degradation pathway that involved the catabolism via DEDS was proposed, which indicated DEDS were further mineralized into carbon dioxide (CO2), bacterial cells, and sulfate (SO4 (2-)) through the transformation of element sulfur and ethyl aldehyde. Degradation kinetics for EM and DEDS with different initial concentrations by strain WL2 were evaluated using Haldane-Andrews model with maximum specific degradation rates of 3.13 and 1.33 g g(-1) h(-1), respectively, and maximum degradation rate constants of 0.522 and 0.175 h(-1) using pseudo-first-order kinetic model were obtained. Results obtained that aerobic degradation of EM by strain WL2 was more efficient than those from previous studies. Substrate range studies of strain WL2 demonstrated its ability to degrade several mercaptans, disulfides, aldehydes, and methanol. All the results obtained highlight the potential of strain WL2 for the use in the biodegradation of volatile organic sulfur compounds (VOSCs).

Impact of p-cresol on hydrogen sulfide and ammonia treatment by biotrickling filter and the production of nitrous oxide.

Biotrickling filter (BTF) is often used for purification of waste gas from swine houses, with vital information still needed regarding interaction effects among multiple gas pollutants removal and also the formation of byproducts especially nitrous oxide (N2O, a strong greenhouse gas) due to the relative high NH3 concentration level compared to other gases. In this study, gas removal and N2O production were compared between two BTFs, where the inlet gas of BTF-1 contained NH3 and H2S while p-cresol was additionally supplied to BTF-2. At inlet load (IL) between 3.67 and 18.91 g m-3 h-1, removal efficiencies of NH3 exceeded 95% for both BTFs. As alternative strategy, adding thiosulfate improved H2S removal. Interestingly, presence of p-cresol to some extent promoted H2S removal at IL of 0.56 g m-3 h-1possibly due to effect on pH value of circulating solution. Similar to NH3, removal efficiencies of p-cresol were higher than 95% at an average IL of 2.98 g m-3 h-1. Gas residence time, pH of circulating solution and inlet loading were identified as key factors affecting BTF performance, but the response of individual gas compound to these factors was not consistent. Overall, p-cresol enhanced N2O generation although the effects were not always significant. High-throughput sequencing results showed that Proteobacteria accounted for the largest proportion of relative abundance and BTF-2 had much richer microbial diversity compared to BTF-1. Thermomonas, Comamonas, Rhodanobacter and other bacterial genus capable of denitrification were detected in both BTFs, and their corresponding abundances in BTF-2 (10.9%, 8.7% and 5.2%) were all greater than those in BTF-1 (0.4%, 0.3% and 2.0%), indicating that more denitrification may occur within BTF-2 and higher N2O could have been generated. This study provided evidence that organic gas components, served as carbon source, may increase the N2O production from BTF when treating waste gases containing NH3.

Reversible Surface Engineering of Cellulose Elementary Fibrils: From Ultralong Nanocelluloses to Advanced Cellulosic Materials.

Cellulose nanofibrils (CNFs) are supramolecular assemblies of cellulose chains that provide outstanding mechanical support and structural functions for cellulosic organisms. However, traditional chemical pretreatments and mechanical defibrillation of natural cellulose produce irreversible surface functionalization and adverse effects of morphology of the CNFs, respectively, which limit the utilization of CNFs in nanoassembly and surface functionalization. Herein, this work presents a facile and energetically efficient surface engineering strategy to completely exfoliate cellulose elementary fibrils from various bioresources, which provides CNFs with ultrahigh aspect ratios (≈1400) and reversible surface. During the mild process of swelling and esterification, the crystallinity and the morphology of the elementary fibrils are retained, resulting in high yields (98%) with low energy consumption (12.4 kJ g-1). In particular, on the CNF surface, the surface hydroxyl groups are restored by removal of the carboxyl moieties via saponification, which offers a significant opportunity for reconstitution of stronger hydrogen bonding interfaces. Therefore, the resultant CNFs can be used as sustainable building blocks for construction of multidimensional advanced cellulosic materials, e.g., 1D filaments, 2D films, and 3D aerogels. The proposed surface engineering strategy provides a new platform for fully utilizing the characteristics of the cellulose elementary fibrils in the development of high-performance cellulosic materials.