Improved methane production with redox-active/conductive biochar amendment by establishing spatial ecological niche and mediating electron transfer.

The multifunctional roles of biochar as an additive in improving the performance of anaerobic digestion (AD) has not been perfectly understood. In this study, the effects of different biochars on AD and the enhanced mechanisms were explored. The CH4 productions were significantly improved with an increase of 45.9%, 28.3% and 16.5% by amendment with biochar pyrolyzed at 300℃ (BC300), 450℃ (BC450) and 600℃ (BC600), respectively. The tightly-bound communities were established on biochar at the initial stage of fermentation and functional microbes were selectively enriched/colonized in biochar-amended systems. Distinctive loosely-bound microbial communities were observed in BC300 and BC600 amended systems, among which electroactive Desulforhabdus and Clostridiales were the dominant bacteria. Biochar amendments also led to the formation of distinctive spatial ecological niches and the selection preference of microbes for specific spatial locations. These results provided new insights in revealing the potential mechanisms of enhanced AD performance by biochar amendment.

Enhancement of phenol biodegradation: Metabolic division of labor in co-culture of Stenotrophomonas sp. N5 and Advenella sp. B9.

The aim of this work is to study the synergistic effect of Stenotrophomonas sp. N5 and Advenella sp. B9 co-culture (COC) on enhancement of phenol biodegradation. These two strains utilizing phenol as sole carbon and energy source were isolated from phenol-containing coking wastewater. The results of biodegradation experiment showed the COC of N5 and B9 has stronger capability to degrade phenol than either of mono-culture (MOC). Growth kinetics studies indicated inhibitory effect of phenol on COC was reduced by the interaction of N5 and B9 in COC. The RNA-Seq results demonstrated that phenol biodegradation was enhanced by metabolic division of labor (DOL) in COC based on the expression of key genes for phenol degradation. GO enrichment analysis of differentially expressed genes (DEGs) indicated DEGs between COC and MOC degradation systems are mainly concentrated in the synthesis of cell components, microbial growth and metabolism, and catalytic activity. The expression of 3 transcriptional factors (LysR, Two-component system response regulator, and TetR families) which can regulate degradation of aromatic compounds, was identified beneficial to phenol degradation.

[Performance and Mechanisms of Advanced Nitrogen Removal via FeS-driven Autotrophic Denitrification Coupled with ANAMMOX].

Synergy among members of complex microbial communities in the transformation of elements is a key ecological regulation strategy in nature. Making full use of this phenomenon and achieving functional combinations of different microorganisms may have a significant effect on developing new wastewater treatment processes. In this study, nitrogen-containing pollutants were applied in a static batch experiment. The dosage of FeS, the ratio of NO3--N/NO2--N, and the ratio of ANAMMOX (AN) to autotrophic denitrification (AD) biomass were the controlled reaction conditions. The cooperation mechanism resulting from the metabolic complementation of AN and AD is discussed, and the concept of a (AN+AD)TN 0 nitrogen removal process is proposed. This study showed that the excessive dosage of FeS could ensure the more thorough reaction of AD without significantly affecting the metabolic activity of AN bacteria. A complex microbial community was involved in the competition for metabolic substrates when the proportion of NO2--N in the electron acceptor was increased, resulting in a negative impact on the removal of TN. The increase of AN biomass contributed to the strengthening of the cooperation between AN and AD. When the stoichiometric ratio of NH4+-N to NO3--N was less than 0.85, TN could be completely removed. The results showed that a more effective wastewater treatment process may be established by understanding the interactions between microorganisms, and by manipulating or regulating complex microbial communities. This could achieve the efficient removal of pollutants under low material consumption conditions.

[Behavior and Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) in Coking Wastewater of A/O2 and A/O/H/O Processes].

Polycyclic aromatic hydrocarbons (PAHs) are typical organic pollutants found in coking wastewater, and their behavior and reduction can be affected by different treatment processes. Based on these considerations, this study investigated the behaviors of PAHs in coking wastewater under A/O2 and A/O/H/O treatment processes, respectively. In order to evaluate variations in PAH removal under two different treatment processes, samples were taken from different treatment units for quantification of PAHs using gas chromatography-mass spectrometry. Results showed that PAHs were barely degraded in anaerobic tanks of either treatment process and accumulated much higher concentrations than in aerobic and hydrolytic tanks. While low molecular weight PAHs (LMW PAHs) in aqueous phase from anaerobic tanks were degraded effectively in aerobic tanks, high molecular weight PAHs (HMW PAHs) mostly accumulated in the sludge phase; these potentially pose a higher environmental risk and therefore need to be treated separately. Moreover, the A/O/H/O process showed higher degradation of PAHs bioavailability and higher removal effectiveness for PAHs with four or more benzene rings than the A/O2 process; this is attributed to the hydrolytic tank's ability to promote hydrolysis of macromolecular organic compounds and therefore improve biodegradability of PAHs. Comprehensive results from the study indicated that the A/O/H/O process is more advantageous for degradation of PAHs than the A/O2 process.

[Characteristic of Benzo[a]pyrene Anaerobic Degradation by Phenol Co-substrate and Microbial Communities from Two Types of Sludge].

Benzo[a]pyrene (BaP) is a typical representative of PAHs in coking wastewater and priority-controlled pollutants in the coking industry; its response characteristics with microorganisms and the methods to promote its degradation are worth studying. On the other hand, because the inoculated sludge for the adjustment and operation of newly-constructed coking wastewater treatment plants comes from municipal sludge or other coking plants, currently, the study of the microbial properties of different sludges', sludge availability, and the conditions that influence these properties are lacking. On account of the above perspectives, an experiment to study and compare the durability of municipal sludge and coking sludge, and their ability to degrade BaP was carried out. An anaerobic reactor was selected for the experiment and anaerobic-activated sludges were collected from a coking wastewater processing unit and a municipal wastewater plant. Then, 10 mg·L-1 of BaP alone and BaP with phenol as a co-metabolic carbon source was added to the coking and municipal sludge samples, respectively, for comparison experiments to study the microbial degradation of BaP and its dynamics. Moreover, high-throughput sequencing technology was also used to analyze the changes in the microbial community structure before and after the degradation experiment. The results showed that:① Both sludges were capable of degrading BaP, but municipal sludge showed a higher degradation efficiency than coking sludge; ② Adding phenol as co-substrate promoted the biodegradation of BaP in both sludges. When BaP was the sole carbon source, the half-life of BaP in the two sludges was 155.41 d and 116.3 d respectively. After the addition of phenol, the half-life was reduced to 81.25 d and 38.44 d, respectively; ③ According to the analysis of the microbial community structure, the community composition in both sludges changed markedly. Moreover, the microbial community in the municipal sludge showed a more evident change than that of the coking sludge. In the coking sludge, the dominant bacteria community changed a little after acclimation, most of the observed bacteria were previously reported common PAH-degrading strains. In contrast, the dominant bacteria community in the municipal sludge varied greatly after acclimation, and the most abundant bacteria were not common PAH-degrading strains. In addition, some frequently reported PAHs-degrading bacteria such as Bacillus sp., Pseudomonas, Achromobacter, and Sphingomonas sp., were identified in both the sludges and were present in high abundance. The results indicated that municipal sludge utilized BaP more actively than coking sludge; this phenomenon can be explained by the fact that municipal sludge contained a higher diversity of microbes that were involved in the degradation of BaP. Furthermore, the presence of phenol promoted the degradation of PAHs like BaP. Therefore, we proposed that the PAHs in coking sludge discharge might be reduced by the addition phenol and municipal wastewater.

[Evaluation of Advanced Nitrogen Removal from Coking Wastewater Using Sulfide Iron-containing Sludge as a Denitrification Electron Donor].

In general, it is difficult to reach the total nitrogen discharge standard in the effluent after municipal and industrial wastewater treatment. The problems hindering advanced denitrification include an unstable C/N ratio in the influent wastewater, increased hydraulic loading with increasing reflux ratio, reduced reaction kinetics, high energy consumption, and secondary pollution and high sludge yield resulting from addition of organic carbon sources. Therefore, deep denitrification with the advantages of energy savings and easy operation is urgently needed. To address these issues, chemical iron sulfide sludge, collected after the pretreatment of sulfur-containing industrial wastewater, was used as a solid-phase electron donor to perform advanced denitrification using autotrophic denitrifiers. In this study, the secondary biological effluent of coking wastewater was the influent for denitrification and the performance of denitrification, transformation of sulfide and iron in the sludge, and microbial community changes were investigated. The optimal reaction conditions and effect range of the technology for deep denitrification of wastewater were then calculated. When the concentrations of NO3--N and NO2--N in the influent were (74.54±0.57) and (1.11±0.19) mg·L-1, respectively, the corresponding concentrations in the effluent were reduced to (2.78±1.08) and (2.87±0.71) mg·L-1, respectively, with a hydraulic retention time (HRT) of 18 h. The removal rate of TON (NO3--N+NO2--N) was as high as 90.0%, of which the reduction rate of NO3--N and the accumulation rate of NO2--N were 12.06 and 7.74 mmol·(L·d)-1, respectively. This study showed that the use of chemical sulfide iron sludge as an electron donor for deep denitrification is of practical importance, as it could simplify the subsequent treatment of sulfur- and iron-rich chemical sludge, finally reaching the goal of resource utilization.

[Aerobic Degradation and Microbial Community Succession of Coking Wastewater with Municipal Sludge].

Coking wastewater is a typical industrial wastewater with high toxicity. Its treatment with biological processes is often challenging because it contains constituents inhibiting microbial activity. To study the inhibitory effect and possible acclimation of microbes in coking wastewater treatment, municipal sludge was inoculated into coking wastewater. Time-dependent concentrations of COD, phenol, ammonia nitrogen, and thiocyanide in coking wastewater were analyzed. The microbial community structure was investigated by the Illumina high-throughput sequencing technology during inoculation. The results showed that COD began to decrease after 16 h and 97.1% of phenol disappeared after 40 h. Thiocyanide began to degrade at 72 h and was undetectable after 96 h. Accordingly, the concentration of ammonia increased as the thiocyanide concentrations decreased. High-throughput pyrosequencing analysis showed that the microbial community structure and species richness varied at different culture stages. In the stage of phenol degradation, the abundance of Acinetobacter and Pseudomonas increased rapidly; the species richness was 13.04% of the community at 48 h. In the stage of thiocyanate degradation, Sphingobacterium,Brevundimonas,Lysobacter, and Chryseobacterium were the dominant bacteria and were 16.13% of the community at 96 h. At 144 h, Fluviicola,Stenotrophomonas, and Thiobacillus became the dominant species and were 22.45% of the community abundance. The results showed that municipal sludge can rapidly overcome the toxicity of coking wastewater because the pollutants are degraded rapidly. The microbial community structure changed as wastewater components were degraded. Environmental factors and the competition among bacteria played a key role in microbial community succession.

Sequential dynamic artificial neural network modeling of a full-scale coking wastewater treatment plant with fluidized bed reactors.

This study proposed a sequential modeling approach using an artificial neural network (ANN) to develop four independent models which were able to predict biotreatment effluent variables of a full-scale coking wastewater treatment plant (CWWTP). Suitable structure and transfer function of ANN were optimized by genetic algorithm. The sequential approach, which included two parts, an influent estimator and an effluent predictor, was used to develop dynamic models. The former parts of models estimated the variations of influent COD, volatile phenol, cyanide, and NH4 (+)-N. The later parts of models predicted effluent COD, volatile phenol, cyanide, and NH4 (+)-N using the estimated values and other parameters. The performance of these models was evaluated by statistical parameters (such as coefficient of determination (R (2) ), etc.). Obtained results indicated that the estimator developed dynamic models for influent COD (R (2) = 0.871), volatile phenol (R (2) = 0.904), cyanide (R (2) = 0.846), and NH4 (+)-N (R (2) = 0.777), while the predictor developed feasible models for effluent COD (R (2) = 0.852) and cyanide (R (2) = 0.844), with slightly worse models for effluent volatile phenol (R (2) = 0.752) and NH4 (+)-N (R (2) = 0.764). Thus, the proposed modeling processes can be used as a tool for the prediction of CWWTP performance.

Novel insights into anoxic/aerobic(1)/aerobic(2) biological fluidized-bed system for coke wastewater treatment by fluorescence excitation-emission matrix spectra coupled with parallel factor analysis.

Fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) was applied to investigate the contaminant removal efficiency and fluorescent characteristic variations in a full scale coke wastewater (CWW) treatment plant with a novel anoxic/aerobic(1)/aerobic(2) (A/O(1)/O(2)) process, which combined with internal-loop fluidized-bed reactor. Routine monitoring results indicated that primary contaminants in CWW, such as phenols and free cyanide, were removed efficiently in A/O(1)/O(2) process (removal efficiency reached 99% and 95%, respectively). Three-dimensional excitation-emission matrix fluorescence spectroscopy and PARAFAC identified three fluorescent components, including two humic-like fluorescence components (C1 and C3) and one protein-like component (C2). Principal component analysis revealed that C1 and C2 correlated with COD (correlation coefficient (r)=0.782, p<0.01 and r=0.921, p<0.01), respectively) and phenols (r=0.796, p<0.01 and r=0.914, p<0.01, respectively), suggesting that C1 and C2 might be associated with the predominating aromatic contaminants in CWW. C3 correlated with mixed liquor suspended solids (r=0.863, p<0.01) in fluidized-bed reactors, suggesting that it might represent the biological dissolved organic matter. In A/O(1)/O(2) process, the fluorescence intensities of C1 and C2 consecutively decreased, indicating the degradation of aromatic contaminants. Correspondingly, the fluorescence intensity of C3 increased in aerobic(1) stage, suggesting an increase of biological dissolved organic matter.

Catalytic dehydration of fructose to 5-hydroxymethylfurfural over Nb2O5 catalyst in organic solvent.

The catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) in DMSO was performed over Nb2O5 derived from calcination of niobic acid at various temperatures (300-700 °C). The catalysts were characterized by powder X-ray diffraction, N2 physical adsorption, temperature-programed desorption of NH3, n-butylamine titration using Hammett indicators, infrared spectroscopy of adsorbed pyridine, and X-ray photoelectron spectroscopy. It was found that both catalytic activity and surface acid sites decrease with increasing calcination temperatures. The Nb2O5 derived from calcination of niobic acid at 400 °C reveals the maximum yield of HMF among all the catalysts, although the amount of acid sites on the catalyst is lower than that on the sample calcined at 300 °C. The results suggest that the presence of larger amounts of strong acid sites on the surface of the Nb2O5 calcined at 300 °C may promote side reactions. The Nb2O5 prepared at 400 °C shows 100% fructose conversion with 86.2% HMF yield in DMSO at 120 °C after 2 h. The activity of the catalyst decreases gradually during recycle because of coke deposition; however, it can be fully recovered by calcination at 400 °C for 2 h, suggesting that this catalyst is of significance for practical applications.

Preparation of trimethylchlorosilane-modified acid vermiculites for removing diethyl phthalate from water.

A hybrid organic-inorganic material based on vermiculite was prepared to remove diethyl phthalate (DEP) from aqueous solution. Natural vermiculite was activated with HCl to improve the specific surface area and was then modified by silanization using trimethylchlorosilane. Organovermiculite prepared by ion exchange with hexadecyl trimethylammonium bromide (HDTMAB) was also tested for comparison. The leaching of 2 mol L(-1) HCl at 80°C increased the specific surface area of vermiculite from 14.4 to 500.0m(2)g(-1), and the average pore-diameter was decreased from 7.90 nm to 2.75 nm. Fourier transform infrared spectroscopy (FTIR) spectra indicated that trimethysilyl groups were grafted covalently on the surface of acid vermiculites. The specific surface area of trimethylchlorosilane-modified acid vermiculites (TMAVs) (355.4 m(2) g(-1)) was much larger than that of organovermiculite (6.0 m(2) g(-1)). The isotherm adsorption experiments of DEP showed that TMAVs exhibited linear isotherms, suggesting that the uptake of DEP was controlled by partitioning mechanism. The maximal partition coefficient (K(d)) of TMAVs was 3.1 times higher than that of organovermiculite, implying that TMAVs had stronger organic affinity than organovermiculite. The results demonstrate that the adsorption capacity and mechanism of organoclays were controlled by the specific surface area and organic loading, whereas the length of alkyl chain of organic modifier was not the key factor.

[Analysis of novel style biological fluidized bed A/O combined process in dyeing wastewater treatment].

A novel biological fluidized bed was designed and developed to deal with high-concentration refractory organic industrial wastewater. From 12 successful projects, three cases of dyeing wastewater treatment projects with the scale of 1200, 2000 and 13000 m3/d respectively were selected to analyze the principle of treating refractory organic wastewater with fluidized bed technology and discuss the superiority of self-developed biological fluidized bed from the aspects of technical and economic feasibility. In the three cases, when the hydraulic retention time (HRT) of biological system were 23, 34 and 21. 8 h, and the volume loading of influents (COD) were 1.75, 4.75 and 2.97 kg/(m3 x d), the corresponding COD removal were 97.3%, 98.1% and 95.8%. Furthermore the operating costs of projects were 0.91, 1.17 and 0.88 yuan per ton of water respectively. The index of effluent all met the 1st grade of Guangdong Province wastewater discharge standard. Results showed that the biological fluidized bed had characteristics of shorter retention time, greater oxygen utilization rate, faster conversion rate of organic pollutants and less sludge production, which made it overcome the shortcomings of traditional methods in printing and dyeing wastewater treatment. Considering the development of technology and the combination of ecological security and recycling resources, a low-carbon wastewater treatment process was proposed.

DFT and MP2 investigations of L-proline and its hydrated complexes.

A theoretical study of L-proline-nH(2)O (n = 1-3) has been performed using the hybrid DFT-B3LYP and MP2 methods together with the 6-311++G(d,p) basis set. The results show that the P2 conformer is energetically favorable when forming a hydrated structure, and the hydration of the carboxyl group leads to the greatest stability. For hydrated complexes, the adiabatic and vertical singlet-triplet excitation energies tend to decrease with the addition of water molecules. The hydration energy indicates that in the hydrated complexes the order of stability is: binding site 2 > binding site 1 > binding site 3, and binding site 12 > binding site 23 > binding site 13. As water molecules are added, the stabilities of these hydrated structures gradually increase. In addition, an infrared frequency analysis indicated that there are some differences in the low-frequency range, which are mainly dominated by the O-H stretching or bending vibrations of different water molecules. All of these results should aid our understanding of molecular behavior and provide reference data for further studies of biological systems.

DNA sequencing of a plasmid with virulence from marine fish pathogen Vibrio anguillarum.

DNA sequence of a plasmid pEIB1 associated with virulence from the marine fish pathogen Vibrio anguillarum was determined using the methods of restriction endonuclease digestion, subcloning, and primer walking. The whole length of obtained pEIB1 DNA sequence was 66 164 bp, and the overall G+C content of DNA sequence is 42.7%. This sequence encodes 44 open reading frames containing the genes of DNA replication, biosynthesis and regulation of the siderophore anguibactin and transport of ferric-anguibactin complexes.

Expression, purification, and characterization of recombinant Saccharomyces cerevisiae adenosine kinase.

Adenosine kinase (AK), a key enzyme in the regulation of the cellular concentrations of adenosine (A), is an important physiological effector of many cells and tissues. In this article, we reported that ak, which encoded adenosine kinase, was cloned from Saccharomyces cerevisiae, sequenced, and overexpressed in E. coli using the pET16b expression system, and the recombinant protein was purified to apparent homogeneity using conventional protein purification techniques. Kinetic analysis of S. cerevisiae AK revealed K(m) values of (3.5+/-0.2) micromol/L for adenosine and (100.0+/-11.0) micromol/L for ATP, with k(cat) of (1530+/-20) min(-1) for adenosine and (1448+/-25) min(-1) for ATP. The determination of the K(m) value for other nucleosides and deoxynucleoside indicated that the nucleoside specificity of this enzyme from yeast was quite high.