Identification and Characterization of a New Alkaline SGNH Hydrolase from a Thermophilic Bacterium Bacillus sp. K91

( Tingting Yu ),( Junmei Ding ),( Qingxia Zheng ),( Nanyu Han ),( Jialin Yu ),( Yunjuan Yang ),( Junjun Li ),( Yuelin Mu ),( Qian Wu ),( Zunxi Huang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.4

est19 is a gene from Bacillus sp. K91 that encodes a new esterase. A comparison of the amino acid sequence showed that Est19 has typical Ser-Gly-Asn-His (SGNH) family motifs and could be grouped into the SGNH hydrolase family. The Est19 protein was functionally cloned, and expressed and purified from Escherichia coli BL21(DE3). The enzyme activity was optimal at 60°C and pH 9.0, and displayed esterase activity towards esters with short-chain acyl esters (C2-C6). A structural model of Est19 was constructed using phospholipase A1 from Streptomyces albidoflavus NA297 as a template. The structure showed an α/β-hydrolase fold and indicated the presence of the typical catalytic triad Ser49-Asp227-His230, which were further investigated by site-directed mutagenesis. To the best of our knowledge, Est19 is a new member of the SGNH hydrolase family identified from thermophiles, which may be applicable in the industrial production of semisynthetic β-lactam antibiotics after modification.

Detection of reactive oxygen species generated by microwave electrodeless discharge lamp and application in photodegradation of H2S

Jiang Yu,Yang Yu,Tingting Zhang,Liqiong Zheng 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.7

The photodegradation of hydrogen sulfide (H2S) was examined using a self-made microwave electrodeless discharge lamp (MEDL). The features of the MEDL had been tested. The results showed that the MEDL absorbed 18.3, 32.7 and 41.8W power at the microwave (MW) output power of 165, 330 and 660W, respectively. The intensity of the emitted light increased with increasing MW output power. The reactive oxygen species (ROS) generated by irradiated air and nitrogen were detected, respectively. It was illustrated that the irradiated air could generate a number of ROS, at least including 1O2 and •OH. And the amount of ROS increased with increasing MW output power. In photodegradation of H2S process, the effects of MW output power and gas composition were investigated. The removal efficiency of H2S under nitrogen was obviously lower compared with that under air. The removal efficiency of H2S increased with increasing MW output power.

외국인직접투자가 중국 부동산시장에 미치는 효과에 관한 실증 연구

우정정(Tingting YU),최태영(Tae-Yeong CHOI) 한국수산해양교육학회 2021 水産海洋敎育硏究 Vol.33 No.2

Performance study of g-C3N4/carbon black/BiOBr@Ti3C2/MoS2 photocatalytic fuel cell for the synergistic degradation of different types of pollutants

Guo Huilin,Yu Tingting,Zhao Lei,Qian Jun,Yu Jiahe,Zhang Yu,Teng Yongyue,Zhu Chunshui,Yang Tao,Chen Wenbin,Gong Picheng,Jiang Cuishuang,Gao Changfei,Yang Bing,Yang Chenyu 한국탄소학회 2023 Carbon Letters Vol.33 No.3

In this study, a bipolar visible light responsive photocatalytic fuel cell (PFC) was constructed by loading a Z-scheme g-C3N4/carbon black/BiOBr and a Ti3C2/MoS2 Schottky heterojunction on the carbon brush to prepare the photoanode and photocathode, respectively. It greatly improved the electron transfer and achieved efficient degradation of organic pollutants such as antibiotics and dyes simultaneously in two chambers of the PFC system. The Z-scheme g-C3N4/carbon black/BiOBr formed by adding highly conductive carbon black to g-C3N4/BiOBr not only effectively separates the photogenerated carriers, but also simultaneously retains the high reduction of the conduction band of g-C3N4 and the high oxidation of the valence band of BiOBr, improving the photocatalytic performance. The exceptional performance of Ti3C2/MoS2 Schottky heterojunction originated from the superior electrical conductivity of Ti3C2 MXene, which facilitated the separation of photogenerated electron–hole pairs. Meanwhile, the synergistic effect of the two photoelectrodes further improved the photocatalytic performance of the PFC system, with degradation rates of 90.9% and 99.9% for 50 mg L−1 tetracycline hydrochloride (TCH) and 50 mg L−1 rhodamine-B (RhB), respectively, within 180 min. In addition, it was found that the PFC also exhibited excellent pollutant degradation rates under dark conditions (79.7%, TCH and 97.9%, RhB). This novel pollutant degradation system is expected to provide a new idea for efficient degradation of multiple pollutant simultaneously even in the dark.

Nitrogen self‑doped porous carbon nanosheets derived from azo dye flocs for efficient supercapacitor electrodes

Tingting Wei,Liang Wu,Feng Yu,Yin Lv,Long Chen,Yulin Shi,Bin Dai 한국탄소학회 2019 Carbon Letters Vol.29 No.5

The present work introduces a new method for the recycling of waste flocculation sludge to prepare electrode materials for supercapacitor. Hazardous azo dye was removal from textile dying wastewater by a new chitosan-based flocculant, and the generated dye sludge flocs was used as a nitrogen-containing precursor for the fabrication of N-doped carbon materials. The influence of azo dye on specific surface areas, nitrogen content, pore evolution of the resulting products and their electrochemical performance were investigated in detail. The results demonstrated a dual role of azo dye worked as both a nitrogen resource and pore-forming agent. The resulting N-doped carbon nanosheets derived from azo dye flocs demonstrated high electrochemical capacitance and good stability for supercapacitor electrode, which is attributed to the unique nitrogen doping, higher specific surface area and efficient charge transfer ability.

Anaerobic Ammonium-Oxidizing Bacteria in Cow Manure Composting

( Tingting Wang ),( Lijun Cheng ),( Wenhao Zhang ),( Xiuhong Xu ),( Qingxin Meng ),( Xuewei Sun ),( Huajing Liu ),( Hongtao Li ),( Yu Sun ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.7

Composting is widely used to transform waste into valuable agricultural organic fertilizer. Anaerobic ammonium-oxidizing (anammox) bacteria play an important role in the global nitrogen cycle, but their role in composting remains poorly understood. In the present study, the community structure, diversity, and abundance of anammox bacteria were analyzed using cloning and sequencing methods by targeting the 16S rRNA gene and the hydrazine oxidase gene (hzo) in samples isolated from compost produced from cow manure and rice straw. A total of 25 operational taxonomic units were classified based on 16S rRNA gene clone libraries, and 14 operational taxonomic units were classified based on hzo gene clone libraries. The phylogenetic tree analysis of the 16S rRNA gene and deduced HZO protein sequences from the corresponding encoding genes indicated that the majority of the obtained clones were related to the known anammox bacteria Candidatus “Brocadia,” Candidatus “Kuenenia,” and Candidatus “Scalindua.” The abundances of anammox bacteria were determined by quantitative PCR, and between 2.13 × 10⁵ and 1.15 × 10⁶ 16S rRNA gene copies per gram of compost were found. This study provides the first demonstration of the existence of anammox bacteria with limited diversity in cow manure composting.

Lactic acid bacterial inoculant effects on the vitamin content of alfalfa and Chinese leymus silage

Tingting Jia,Zhiqiang Sun,Run Gao,Zhu Yu 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.12

Objective: Information regarding the vitamin content of silage is limited. This study investigated the changes in the vitamin content of alfalfa and Chinese leymus silages with or without a lactic acid bacterial inoculant. Methods: Alfalfa at the early flowering stage and Chinese leymus at the full-bloom stage were harvested. The treatments for each forage type were control (deionized water only) and 1×106 colony-forming units Lactobacillus plantarum (LP)/g fresh matter. After 45 days of ensiling, all silages were sampled for evaluating the vitamin content, fermentation quality and chemical composition. Results: The LP inoculant decreased the pH value and ammonia nitrogen content of the alfalfa and Chinese leymus silages and significantly (p<0.05) increased the lactic acid, acetic acid concentrations and Flieg’s points. Prior to ensiling, the levels of five B-group vitamins (thiamin, riboflavin, niacin, pantothenic acid, and pyridoxine) and α-tocopherol in alfalfa were significantly (p<0.01) higher than those in Chinese leymus. Ensiling decreased the levels of the five B-group vitamins in both alfalfa and Chinese leymus while increasing the α-tocopherol content of Chinese leymus. The thiamin, riboflavin, niacin and pantothenic acid levels in the LP-treated silage were significantly (p<0.05) lower than those in the untreated silage for the alfalfa and Chinese leymus. The α-tocopherol content in the LP-treated alfalfa silage was significantly (p<0.05) higher than that in the untreated alfalfa silage. There was no significant (p>0.05) difference in pyridoxine content between the untreated and LP-treated silages for both forages. Conclusion: With or without LP inoculation, the levels of the five B-group vitamins (thiamin, riboflavin, niacin, pantothenic acid, and pyridoxine) in alfalfa and Chinese leymus decreased after 45 days of ensiling, while the α-tocopherol content of Chinese leymus increased. The LP inoculant improved the fermentation quality of both the alfalfa and Chinese leymus silages but increased the thiamin, riboflavin, niacin, and pantothenic acid loss in the two forages after fermentation.

Biosorption of Lead(II) by Arthrobacter sp. 25: Process Optimization and Mechanism

( Yu Jin ),( Xin Wang ),( Tingting Zang ),( Yang Hu ),( Xiaojing Hu ),( Guangming Ren ),( Xiuhong Xu ),( Juanjuan Qu ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.8

In the present work, Arthrobacter sp. 25, a lead-tolerant bacterium, was assayed to remove lead(II) from aqueous solution. The biosorption process was optimized by response surface methodology (RSM) based on the Box-Behnken design. The relationships between dependent and independent variables were quantitatively determined by second-order polynomial equation and 3D response surface plots. The biosorption mechanism was explored by characterization of the biosorbent before and after biosorption using atomic force microscopy (AFM), scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The results showed that the maximum adsorption capacity of 9.6 mg/g was obtained at the initial lead ion concentration of 108.79 mg/l, pH value of 5.75, and biosorbent dosage of 9.9 g/l (fresh weight), which was close to the theoretically expected value of 9.88 mg/g. Arthrobacter sp. 25 is an ellipsoidalshaped bacterium covered with extracellular polymeric substances. The biosorption mechanism involved physical adsorption and microprecipitation as well as ion exchange, and functional groups such as phosphoryl, hydroxyl, amino, amide, carbonyl, and phosphate groups played vital roles in adsorption. The results indicate that Arthrobacter sp. 25 may be potentially used as a biosorbent for low-concentration lead(II) removal from wastewater.

Seasonal Variation and Sources of Heavy Metals in Urban Street Dusts and River Sediments of Dongluo River Watershed in Ji’nan City, China

Tingting Duan,Shanjun Liu,Dongying Wang,Jiashen Feng,Ningning Song,Yanxin Yu,Yingxia Li 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.5

Due to intense human activities, urban street dusts and river sediments are usually polluted by heavy metals. This study investigated the seasonal variations (summer and winter) of pollution level, spatial distribution and potential sources of heavy metals in street dusts (SD) and river sediments (RS) of Dongluo River watershed, Ji’nan, China. Results showed cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb) and zinc (Zn) contents were 3.5 (8.6), 3.0 (1.4), 4.9 (2.6), 4.1 (1.1) and 3.9 (4.0)-fold of their geochemical soil background values (BGV) of Shandong Province, China in summer (winter). Mercury (Hg) and arsenic (As) contents were lower than their background values in both summer and winter. The differences of Cd, Cr, Cu, Pb, Zn, Mn and As contents in river sediments between winter and summer were not statistically significant. The correlation coefficients between metal contents and the distance between sampling sites and the east-west boundary of study area were higher in summer than those in winter. Based on principal component analysis (PCA) and multivariate linear regression (MLR), coal combustion and traffic-related sources were the main sources in winter, and agricultural activities and traffic-related sources were the main sources in summer.

Nitrogen self-doped porous carbon nanosheets derived from azo dye flocs for efficient supercapacitor electrodes

Wei Tingting,Wu Liang,Yu Feng,Lv Yin,Chen Long,Shi Yulin,Dai Bin 한국탄소학회 2019 Carbon Letters Vol.29 No.5

The present work introduces a new method for the recycling of waste flocculation sludge to prepare electrode materials for supercapacitor. Hazardous azo dye was removal from textile dying wastewater by a new chitosan-based flocculant, and the generated dye sludge flocs was used as a nitrogen-containing precursor for the fabrication of N-doped carbon materials. The influence of azo dye on specific surface areas, nitrogen content, pore evolution of the resulting products and their electrochemical performance were investigated in detail. The results demonstrated a dual role of azo dye worked as both a nitrogen resource and pore-forming agent. The resulting N-doped carbon nanosheets derived from azo dye flocs demonstrated high electrochemical capacitance and good stability for supercapacitor electrode, which is attributed to the unique nitrogen doping, higher specific surface area and efficient charge transfer ability.