Production of a Thermostable Metal-tolerant Laccase from Trametes versicolor and its Application in Dye Decolorization

Zhu Youshuang,Zhang Haibo,Cao Mingle,Wei Zhenzhen,Huang Feng,Gao Peiji 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.5

Production of laccase using a submerged culture of Trametes versicolor sdu-4 was optimized using a central composite design of the Response Surface Methodology. Optimized conditions gave a laccase yield of 4,213 U/L which was approximately three times of that in basal medium. The laccase was purified to homogeneity using a three-step process. The overall yield of the purification was 58%, with a purification fold of 11.4 and a specific activity of 1320.7 U/mg protein. The molecular mass of the laccase was 60 kDa. The optimum pH values of the enzyme were 2.2, 3.7, and 7 for the oxidations of ABTS, DMP, and syringaldazine, respectively. The enzyme had adaptability to a broad pH range and high temperature and wsa stable at pH 3.0 ~ 10.0. The half-life of this laccase at 70°C was 2.2 h. Methyl red, 2-bromophenol, and 4-bromophenol were oxidized by the purified laccase in the absence of mediators. Purified laccase was effective in the decolorization of several dyes and was not inhibited by Cu^(2+), Mn^(2+), Zn^(2+), Na^+, K^+, Mg^(2+), Ba^(2+), and Ca^(2+) at 5 mM. These excellent characteristics made it a highly attractive candidate for industrial use.

Mutually different tooth surface contact characteristics of a noncircular face gear with intersecting axes

Dawei Liu,Heng Li,Zhenzhen Lv,Yuetong Cao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

The noncircular face gear (NFG) with intersecting axes is composed of a spur gear and a NFG, which can realize the reduced and variable-speed integrated transmission between any intersecting axes. To study the contact characteristics of NFG with intersecting axes, the mutually different tooth surface mathematical model of the NFG with intersecting axes was established, and a tooth surface analysis method based on rotational projection was innovatively proposed. By using this method, the distribution characteristics of contact traces on different tooth profiles can be accurately compared through establishing the comparison reference of the middle plane on gear teeth. At the same time, the effects of installation errors and eccentricity on the contact characteristics of tooth surface were analyzed in detail. Results demonstrate that the change in the same kind of installation error has the same effect on the offset direction of the contact traces on each gear tooth. Under the same installation error, changing the eccentricity of the NFG will cause different changes in the offset of the contact traces on each gear tooth. Finally, a gear transmission device of NFG with intersecting axes was designed and manufactured. The correctness of the contact model and the analysis results were proven by the gear pair rolling experiment, which provides a theoretical basis for the design and installation of NFG with intersecting axes.

Efficacy of combination of endo-xylanase and xylan-debranching enzymes in improving cereal bran utilization in piglet diet

Wang Weiwei,Zheng Dawen,Zhang Zhenzhen,Ye Hui,Cao Qingyun,Zhang Changming,Dong Zemin,Feng Dingyuan,Zuo Jianjun 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.11

Objective: This study was aimed to explore the efficacy of combination of endo-xylanase (Xyn) and xylan-debranching enzymes (arabinofuranosidase, Afd and feruloyl esterase, FE) in improving utilization of bran in piglet diet. Methods: In vitro experiments were firstly conducted to examine the enzymological properties of Xyn, Afd, and FE, concurrent with their effect on degradation of arabinoxylan (Abx) in bran. In vivo experiment was then implemented by allocating two hundred and seventy 35-d-old postweaning piglets into 3 groups (6 replicates/group), which received bran-containing diet supplemented with Xyn (1,600 U/kg) or its combination with Afd (0.8 U/kg) and FE (4 U/kg) or without enzyme. Results: Both Xyn, Afd, and FE are relatively stable against the changes in temperature and pH value. Combining Xyn with Afd and FE had a superiority (p<0.05) over Xyn alone and its combination with Afd or FE in promoting (p<0.05) degradation of Abx in different brans. Combined treatment with Xyn, Afd, and FE was more beneficial than Xyn alone to induce increasing trends (p<0.10) of average daily gain, final body weight and feed efficiency of piglets fed bran-containing diet. Moreover, combination of Xyn, Afd, and FE showed advantages (p<0.05) over Xyn alone in causing reductions (p<0.05) in diarrhea rate and cecal pH value, concurrent with increases (p<0.05) in cecal and colonic acetic acid and total volatile fatty acid concentrations, as well as cecal butyric acid concentration of piglets fed brancontaining diet. Conclusion: Combining Xyn with Afd and FE was more beneficial than Xyn alone in promoting degradation of Abx in bran, along with growth performance and intestinal volatile fatty acid profile of piglets received bran-containing diet. Thereby, combination of Xyn, Afd, and FE had a superior efficacy relative to Xyn alone in improving application of cereal bran in piglet diet. Objective: This study was aimed to explore the efficacy of combination of endo-xylanase (Xyn) and xylan-debranching enzymes (arabinofuranosidase, Afd and feruloyl esterase, FE) in improving utilization of bran in piglet diet.Methods: <i>In vitro</i> experiments were firstly conducted to examine the enzymological properties of Xyn, Afd, and FE, concurrent with their effect on degradation of arabinoxylan (Abx) in bran. <i>In vivo</i> experiment was then implemented by allocating two hundred and seventy 35-d-old postweaning piglets into 3 groups (6 replicates/group), which received bran-containing diet supplemented with Xyn (1,600 U/kg) or its combination with Afd (0.8 U/kg) and FE (4 U/kg) or without enzyme.Results: Both Xyn, Afd, and FE are relatively stable against the changes in temperature and pH value. Combining Xyn with Afd and FE had a superiority (p<0.05) over Xyn alone and its combination with Afd or FE in promoting (p<0.05) degradation of Abx in different brans. Combined treatment with Xyn, Afd, and FE was more beneficial than Xyn alone to induce increasing trends (p<0.10) of average daily gain, final body weight and feed efficiency of piglets fed bran-containing diet. Moreover, combination of Xyn, Afd, and FE showed advantages (p<0.05) over Xyn alone in causing reductions (p<0.05) in diarrhea rate and cecal pH value, concurrent with increases (p<0.05) in cecal and colonic acetic acid and total volatile fatty acid concentrations, as well as cecal butyric acid concentration of piglets fed bran-containing diet.Conclusion: Combining Xyn with Afd and FE was more beneficial than Xyn alone in promoting degradation of Abx in bran, along with growth performance and intestinal volatile fatty acid profile of piglets received bran-containing diet. Thereby, combination of Xyn, Afd, and FE had a superior efficacy relative to Xyn alone in improving application of cereal bran in piglet diet.

An advanced Parallel FPGA Architecture for Bi-directional Motion Estimation

Yangfan Huang,Minjun Deng,Donglian Li,Zhenzhen Li,Mingyan Yu,Cailan Zeng,Yu Zhang,Zhuo Chen,Pengcheng Cao,Ran Liu 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.9

Motion estimation (ME) and motion compensation (MC) are the key elements for frame rate up-conversion (FRUC) system. Fast and accurate motion estimation is the premise of high quality motion compensation. Unlike conventional unidirectional motion estimation which brings holes, overlaps and blocking artifacts, the bi-directional motion estimation does not produce any overlapped pixel or hole in the interpolated frames. As a result, the bi-directional motion estimation has better performance than conventional unidirectional motion estimation. This paper presents an efficient FPGA architecture targeting bi-directional motion estimation hardware implementation. This proposed architecture can achieve real-time processing for 1280x720@60Hz under 200MHz operating frequency. The design is described in Verilog HDL, verified in Virtex5 FPGA platform. Experimental results show that the proposed architecture has high performance and low cost for bi-directional motion estimation algorithm. This architecture can be used for video post-processing system.

Analysis and Development of the CFRP Boring Bar for Stability Improvement

Licheng Lu,Can Ni,Gang Liu,Bo Qian,Qinglong An,Zhenzhen Cao,Liqiang Zhang,Junli Li 한국섬유공학회 2023 Fibers and polymers Vol.24 No.12

Boring bars with a large length-to-diameter ratio have become increasingly indispensable for deep hole machining. However, the dynamic performance of conventional boring bars may be inadequate, resulting in vibrations. In this paper, a novel boring bar with composites and a constrained layer damping structure was fabricated to suppress vibrations during the boring operation. Initially, the configuration of the CFRP boring bar was proposed based on theoretical analysis, and then the modal parameters were calculated using the bending strain energy method and cantilever beam theory. Subsequently, the geometric design parameters were optimized analytically using the finite element method. Modal and cutting tests were then conducted to evaluate the cutting stability of a CFRP boring bar with a length-to-diameter ratio of 8.4. The modal parameters, vibration signals, and cutting force signals were measured and compared with a carbide boring bar. The experimental results indicated that there was a significant improvement in the cutting stability of the CFRP boring bar.