5 research outputs found
DataSheet1_Quantitative source apportionment of heavy metals in atmospheric deposition of a typical heavily polluted city in Northern China: Comparison of PMF and UNMIX.docx
Receptor models are rarely utilized in atmospheric deposition but are often used to identify pollutant sources and quantify their contributions. This article focuses on the soil in atmospheric deposition in a typical polluted city. Atmospheric deposition has become an important route for exogenous heavy metals’ input into ecosystems. In this study, the heavy metals in atmospheric deposition were determined in three monitoring points arranged in Handan City. According to the functional area, fluxes, sources, and accumulation in the soil were explored. The sources of heavy metals were identified by PMF (positive matrix factorization) and UNMIX. The accumulation of heavy metals in the soil was predicted. The results showed that the deposition fluxes in industrial areas were higher than other functional areas. The mean concentrations of 8 heavy metals (Cd, Cr, Cu, Mn, Ni, Pb, Zn, and As) in the atmospheric deposition exceed their background values. PMF identified five major sources and UNMIX analyzed four sources. Similar source apportionment results were acquired via PMF and UNMIX, which were the combustion of fossil fuels, steel-smelting emission, road dust, and industrial sources. Steel-smelter emission was the highest source contributor. Therefore, combining these two models was the most effective approach, and more attention should be paid to mitigating the pollution caused by the industrial activities. The prediction indicated that the accumulation of heavy metals from atmospheric deposition to the soil would increase in 30 years, the growth rate of Cd increased significantly. The results of this study could provide reference in reduction of heavy metal pollution in atmospheric deposition.</p
Characterization of Acidic Compounds in Heavy Petroleum Resid by Fractionation and Negative-Ion Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Analysis
Negative-ion electrospray ionization
(ESI) enabled the direct mass
spectrographic analysis of phenols, naphthenic acids, and neutral
nitrogen compounds in petroleum fractions without prefractionation;
however, ESI results provide few quantitative and structural information
about the analytes: the composition of acidic compounds in heavy oil,
such as distillate resid, is still unclear. In this study, extrography
was used to fractionate oilsands bitumen-derived vacuum-topped bitumen
(VTB) and its maltene and asphaltene fractions into multiple subfractions.
The molecular compositions of acidic functional compounds in the VTB
and its subfractions were analyzed by negative-ion ESI Fourier transform
ion cyclotron resonance mass spectrometry (FT-ICR MS). Extrographic
separation was a necessary step to isolate acidic compounds of various
acidities and/or polarities in vacuum resid fractions to achieve a
systematic analysis. The results showed that the O<sub>2</sub> class
species in VTB were highly condensed phenols and carboxylic acids.
The maltene fraction contained most of the less condensed naphthenic
acids, whereas the asphaltene fraction contained highly condensed
carboxylic acids and phenolic compounds with a bouble-bond equivalent
(DBE) higher than 6. The presence of acids had no significant impact
on the yield of asphaltenes in <i>n</i>-C<sub>7</sub> solvent
precipitation. Acid-free asphaltene fractions, which account for more
than 90 wt % of the asphaltenes, cannot be ionized by negative-ion
ESI
DataSheet1_Distinct laccase expression and activity profiles of Trametes versicolor facilitate degradation of benzo[a]pyrene.docx
A Trametes versicolor isolate from the Changbai Mountain showed promising activity in degrading benzo[a]pyrene (BaP), which is a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) compound. It was hypothesized that the T. versicolor isolate encode BaP-degrading enzymes, among which laccase is mostly sought after due to significant commercial potential. Genome of the T. versicolor isolate was sequenced and assembled, and seven laccase homologues were identified (TvLac1-7) as candidate genes potentially contributing to BaP degradation. In order to further identify the BaP responsive laccases, time-course transcriptomic and proteomic analyses were conducted in parallel on the T. versicolor isolate upon BaP treatment. Homologous laccases showed distinct expression patterns. Most strikingly, TvLac5 was rapidly induced in the secreted proteomes (secretomes), while TvLac2 was repressed. Recombinant laccase expression and biochemical characterization further showed corresponding enzymatic activity profiles, where TvLac5 was 21-fold more effective in BaP degradation compared to TvLac2. Moreover, TvLac5 also showed 3.6-fold higher BaP degrading activity compared to a commercial laccase product of T. versicolor origin. Therefore, TvLac5 was concluded to be a BaP-responsive enzyme from T. versicolor showing effective BaP degradation activity.</p
Table1_Distinct laccase expression and activity profiles of Trametes versicolor facilitate degradation of benzo[a]pyrene.xlsx
A Trametes versicolor isolate from the Changbai Mountain showed promising activity in degrading benzo[a]pyrene (BaP), which is a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) compound. It was hypothesized that the T. versicolor isolate encode BaP-degrading enzymes, among which laccase is mostly sought after due to significant commercial potential. Genome of the T. versicolor isolate was sequenced and assembled, and seven laccase homologues were identified (TvLac1-7) as candidate genes potentially contributing to BaP degradation. In order to further identify the BaP responsive laccases, time-course transcriptomic and proteomic analyses were conducted in parallel on the T. versicolor isolate upon BaP treatment. Homologous laccases showed distinct expression patterns. Most strikingly, TvLac5 was rapidly induced in the secreted proteomes (secretomes), while TvLac2 was repressed. Recombinant laccase expression and biochemical characterization further showed corresponding enzymatic activity profiles, where TvLac5 was 21-fold more effective in BaP degradation compared to TvLac2. Moreover, TvLac5 also showed 3.6-fold higher BaP degrading activity compared to a commercial laccase product of T. versicolor origin. Therefore, TvLac5 was concluded to be a BaP-responsive enzyme from T. versicolor showing effective BaP degradation activity.</p
Table2_Distinct laccase expression and activity profiles of Trametes versicolor facilitate degradation of benzo[a]pyrene.XLSX
A Trametes versicolor isolate from the Changbai Mountain showed promising activity in degrading benzo[a]pyrene (BaP), which is a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) compound. It was hypothesized that the T. versicolor isolate encode BaP-degrading enzymes, among which laccase is mostly sought after due to significant commercial potential. Genome of the T. versicolor isolate was sequenced and assembled, and seven laccase homologues were identified (TvLac1-7) as candidate genes potentially contributing to BaP degradation. In order to further identify the BaP responsive laccases, time-course transcriptomic and proteomic analyses were conducted in parallel on the T. versicolor isolate upon BaP treatment. Homologous laccases showed distinct expression patterns. Most strikingly, TvLac5 was rapidly induced in the secreted proteomes (secretomes), while TvLac2 was repressed. Recombinant laccase expression and biochemical characterization further showed corresponding enzymatic activity profiles, where TvLac5 was 21-fold more effective in BaP degradation compared to TvLac2. Moreover, TvLac5 also showed 3.6-fold higher BaP degrading activity compared to a commercial laccase product of T. versicolor origin. Therefore, TvLac5 was concluded to be a BaP-responsive enzyme from T. versicolor showing effective BaP degradation activity.</p