Highly-efficient catalytic combustion performance of 1,2-dichlorobenzene over mesoporous TiO2–SiO2 supported CeMn oxides: The effect of acid sites and redox sites

Haijun Zhao,Weiliang Han,Fang Dong,Zhicheng Tang 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.64 No.-

High specific surface area CeMn/TiO2–SiO2 catalysts were synthesized and evaluated for the catalytic combustion of 1,2-dichlorobenzene (o-DCB). Mesoporous TiO2–SiO2 supports were prepared by evaporation-induced self-assembly (EISA) method to investigate the promotion of Si on the acid properties of TiO2. Pore structures of TiO2–SiO2 were modulated by controlling the amount of hydrochloric acid during the preparation process of mesoporous supports, and the influence of structures and physicochemical properties of CeMn/TiO2–SiO2 catalysts on the activity and stability of o-DCB catalytic combustion were thoroughly studied. The results showed that Mn cations incorporated into CeO2 fluorite structure caused the formation of more active oxygen species. The active oxygen species and high specific surface area of catalysts played significant roles in o-DCB oxidation reaction. The influence of water on o-DCB catalytic combustion was also studied, and two different observations were obtained at low or high content of water. Due to deposition of Cl species on the surface of catalyst, CeMn/TiO2–SiO2 loses partial activity during o-DCB catalytic combustion, and most of activity could be recovered through Deacon reaction.

Defense responses of sulfur dioxygenase to sulfide stress in the razor clam Sinonovacula constricta

Caifang Chen,Yaoyao Shen,Weiliang Shen,Jing He,Zhihua Lin,Yinghui Dong 한국유전학회 2021 Genes & Genomics Vol.43 No.5

Background Sulfde is a well-known toxicant widely distributed in the culture environment. As a representative burrowing benthic bivalve, the razor clam Sinonovacula constricta is highly sulfde tolerant. Mitochondrial sulfde oxidation is an important way for sulfde detoxifcation, where sulfur dioxygenase (SDO) is the second key enzyme. Objective To investigate the mechanism of sulfde tolerance in S. constricta, the molecular characterization of its SDO (designated as ScSDO) was studied. Methods The cDNA sequence of ScSDO was cloned by RACE technique. The response of ScSDO in gills and livers of S. constricta was investigated during sulfde exposure (50, 150, and 300 μM sulfde) for 0, 3, 6, 12, 24, 48, 72, and 96 h by qRTPCR. Moreover, the temporal expression of ScSDO protein in S. constricta gills after exposure to 150 μM sulfde was detected by Western blot. The subcellular location of ScSDO was identifed by TargetP 1.1 prediction and Western Blot analysis. Results The full-length cDNA of ScSDO was 2914 bp, encoding a protein of 304 amino acids. The deduced ScSDO protein was highly conserved, containing the signature HXHXDH motif of the metallo-β-lactamase superfamily and two metalbinding sites, of which metal-binding site I is known to be the catalytically active center. Subcellular localization confrmed that ScSDO was located only in the mitochondria. Responding to the sulfde exposure, distinct time-dependent increases in ScSDO expression were detected at both mRNA and protein levels. Moreover, the gills exhibited a higher ScSDO expression level than the livers. Conclusions All of our results suggest that ScSDO plays an important role in mitochondrial sulfde oxidation during sulfde stress, making S. constricta highly sulfde tolerant. In addition, as a respiratory tissue, the gills play a more critical role in sulfde detoxifcation.

Performance and Mechanism Analysis of Succinate Production under Different Transporters in Escherichia coli

Xiaozhan Li,Wenming Zhang,Mingke Wu,Fengxue Xin,Weiliang Dong,Hao Wu,Min Zhang,Jiangfeng Ma,Min Jiang 한국생물공학회 2017 Biotechnology and Bioprocess Engineering Vol.22 No.5

Succinic acid is a platform chemical with potential for bio-based synthesis. However, the production of bio-based succinate is limited because of insufficient succinate efflux capacity in the late stage of fermentation. In the present study, three different transporters, which have been reported to be responsible for C4-dicarboxylates transport, were employed for investigation of the transport capacity of succinate in Escherichia coli. After engineered strains were constructed, the fermentative production of succinic acid was studied in serum bottles and 3 L of fermentor. The results demonstrated that engineered strain showed better efflux capacity than control strain under high concentration of succinate. The highest production of succinate was 68.66 g/L, while the NCgl2130 transporter may be the best candidate for succinate export in E. coli. Further research showed that the expression levels and relative enzyme activities involved in the metabolic pathway all increased markedly, and the maximum activities of PPC, PCK, PYK, and MDH increased by 1.50, 1.38, 1.28, and 1.27-fold in recombinant E. coli AFP111/pTrc99a- NCgl2130, respectively. Moreover, the maximum level of intracellular ATP increased by 23.79% in E. coli AFP111/ pTrc99a-NCgl2130. Taken together, these findings indicated that engineered transporters can improve succinate production by increasing key enzyme activities and intracellular ATP levels. To the best of thew authors’ knowledge, this is the first report on a mechanism to improve succinate production by engineered transporters. This strategy set up a foundation for improving the biosynthesis of other C4-dicarboxylates, such as fumaric acid and malic acid.

The fuzzy comprehensive evaluation (FCE) and the principal component analysis (PCA) model simulation and its applications in water quality assessment of Nansi Lake Basin, China

Shiguo Xu,Yixiao Cui,Chuanxi Yang,Shujing Wei,Wenping Dong,Lihui Huang,Changqing Liu,Zongming Ren,Weiliang Wang 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.2

The Fuzzy Comprehensive Evaluation (FCE) and the Principal Component Analysis (PCA) were simulated to assess water quality of the Nansi Lake Basin, China. The membership functions were established via the Nor-Half Sinusoidal Distribution Method, and the weight was calculated via the Exceeding Standard Multiple Method. To enhance the efficiency of extracting principal pollutant, the eigenequation was solved through the Jacobi Method, and the principal components were extracted based on eigenvalue, contribution ratio, accumulating contribution ratio, principal component loading and score. Water quality classification based on “National Surface Water Environmental Quality Standards of China (GB3838-2002) was used to assess the water quality. Considering the difference of the temporal and spatial distribution in average, water quality of Level I was 28.9%, 28.1%, 25.1%, 25.6%, respectively in spring, summer, autumn, and winter, which suggested that water quality in spring and summer was better than in autumn and winter. The order of water quality was Zhaoyang Lake (Level I) > Nanyang Lake (Level I) > Dushan Lake (Level III) > Weishan Lake (Level III and IV). There were four extracted principal components that can replace the fourteen pollutant indexes for assessing water quality. According to the annual mean data of the 1<SUP>st</SUP> principal components, the most important pollutions were heavy metals, including As (0.933), Hg (0.931), Cd (0.929), Cr(VI) (0.926), Pb (0.925), and Cu (0.534). It is proved that the combined FCE-PCA model could provide valuable information in the water quality assessment for the Nansi Lake Basin.

Review : Purification and Characterization of a Novel Extracellular Thermostable Alkaline Protease from Streptomyces sp. M30

( Yan Xin ),( Zhibin Sun ),( Qiongzhen Chen ),( Jue Wang ),( Yicheng Wang ),( Linfeng Luogong ),( Shuhuan Li ),( Weiliang Dong ),( Zhongli Cui ),( Yan Huang ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.11

A novel alkaline protease from Streptomyces sp. M30, SapHM, was purified by ammonium sulfate precipitation, hydrophobic interaction chromatography, and DEAE-Sepharose chromatography, with a yield of 15.5% and a specific activity of 29,070 U/mg. Tryptic fragments of the purified SapHM were obtained by electrospray ionization quadrupole timeof- flight mass spectrometry. Nucleotide sequence analysis revealed that the gene sapHM contained 1,179 bp, corresponding to 392 amino acids with conserved Asp156, His187, and Ser339 residues of alkaline protease. The first 24 amino acid residues were predicted to be a signal peptide, and the molecular mass of the mature peptide was 37.1 kDa based on amino acid sequences and mass spectrometry. Pure SapHM was optimally active at 80°C in 50 mM glycine-NaOH buffer (pH 9.0), and was broadly stable at 0-50°C and pH 4.0-9.0. The protease relative activity was increased in the presence of Ni2+, Mn2+, and Cu2+ to 112%, 113%, and 147% of control, respectively. Pure SapHM was also activated by dimethylformamide, dimethyl sulfoxide, Tween 80, and urea. The activity of the purified enzyme was completely inhibited by phenylmethylsulfonyl fluoride, indicating that it is a serine-type protease. The Km and Vmax values were estimated to be 35.7 mg/ml, and 5 × 104 U/mg for casein. Substrate specificity analysis showed that SapH was active on casein, bovine serum albumin, and bovine serum fibrin.

Axial compressive behavior of concrete-filled steel tube columns with stiffeners

Wei Liang,Jiangfeng Dong,Qingyuan Wang 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.2

In order to reduce the deformation and delay the local buckling of concrete filled steel tube (CFST) columns, strengthening the structures with stiffeners is an effective method. In this paper, a new stiffening method with inclined stiffeners was used to investigate the behaviors of short CFST columns under axial compression. Besides, a three-dimensional nonlinear finite element (FE) model was applied to simulate the mechanical performances, including the total deformation, local buckling, and stress-strain relationship. Revised constitutive models of stiffened steel tube and confined concrete are proposed. A good agreement was achieved between the test and FE results. Furthermore, the calculated results of load capacity by using a simplified method also show a good correlation with experimental data.