The Experts below are selected from a list of 2601 Experts worldwide ranked by ideXlab platform
Cheng Zhou - One of the best experts on this subject based on the ideXlab platform.
-
characterization and overproduction of a thermo alkaline pectate lyase from alkaliphilic bacillus licheniformis with potential in ramie Degumming
Process Biochemistry, 2017Co-Authors: Cheng Zhou, Yanfen XueAbstract:Abstract A thermo-alkaline pectate lyase (BliPelA) gene from an alkaliphilic Bacillus licheniformis strain was cloned and overexpressed in Escherichia coli . Mature BliPelA exhibited maximum activity at pH 11 and 70 °C, and demonstrated cleavage capability on a broad range of substrates such as polygalacturonic acid, pectins, and methylated pectins. The highest specific activity, of 320 U mg −1 , was towards polygalacturonic acid. Significant ramie ( Boehmeria nivea ) fiber weight loss (21.5%) was obtained following enzyme treatment and combined enzyme-chemical treatment (29.3%), indicating a high ramie Degumming efficiency of BliPelA. The total activity of recombinant BliPelA reached 1450.1 U ml −1 with a productivity of 48.3 U ml −1 h −1 under high-cell-density cultivation with a glycerol exponential feeding strategy for 30 h in 1-l fed-batch fermenter, and 1380.1 U ml −1 with a productivity of 57.5 U ml −1 h −1 after 24 h under constant glucose feeding in a 20-l fermenter using E. coli as the host. The enzyme yields reached 4.5 and 4.3 g l −1 in 1-l and 20-l fed-batch fermenters, respectively, which are higher than those of most reported alkaline Pels. Based on these promising properties and high-level production, BliPelA shows great potential for application in ramie Degumming in textile industry.
-
cloning evaluation and high level expression of a thermo alkaline pectate lyase from alkaliphilic bacillus clausii with potential in ramie Degumming
Applied Microbiology and Biotechnology, 2017Co-Authors: Cheng ZhouAbstract:Alkaline pectate lyases (Pels) have potential application in bioscouring of the textile industry. In this study, a thermo-alkaline Pel (BacPelA) gene from an alkaliphilic Bacillus clausii strain was cloned and overexpressed in Escherichia coli. The mature BacPelA exhibited maximum activity at pH 10.5 and 70 °C and showed high cleavage capability on methylated pectins. BacPelA showed the highest specific activity of 936.2 U mg−1 on ≥85% methylated pectin and 675.5 U mg−1 on standard substrate polygalacturonic acid (PGA) upon evaluation of the absorbance at 235 nm (A235). The K m and k cat values for PGA were 0.54 g l−1 and 346.5 s−1, respectively. Moreover, the 3,5-dinitrosalicylic acid (DNS) assay, which detects the released reducing oligogalacturonic acids, was confirmed to be inaccurate and unsuitable for endo-acting pectinase activity assay because of the difference in the reducibility by DNS reagent between the standard galacturonic acid and the catalytic oligomer products. Significant ramie fiber weight loss was observed following treatment with BacPelA (24.8%) and combined enzyme-chemical method (30.9%), which indicated that the Degumming efficiency of BacPelA was the highest of all alkaline and thermostable Pels reported to date. The total activity of the recombinant mature BacPelA reached 8378.2 U ml−1 (A235) by high-cell-density cultivation in fed-batch fermentation with productivity of 239.4 U ml−1 h−1 using E. coli as host, which represents the highest Pel yield reported to date. Therefore, BacPelA, with promising properties for bioscouring, shows potential applications for ramie Degumming in the textile industry.
-
directed evolution and structural analysis of alkaline pectate lyase from the alkaliphilic bacterium bacillus sp strain n16 5 to improve its thermostability for efficient ramie Degumming
Applied and Environmental Microbiology, 2015Co-Authors: Cheng Zhou, Jintong YeAbstract:ABSTRACT Thermostable alkaline pectate lyases have potential applications in the textile industry as an alternative to chemical-based ramie Degumming processes. In particular, the alkaline pectate lyase from Bacillus sp. strain N16-5 (BspPelA) has potential for enzymatic ramie Degumming because of its high specific activity under extremely alkaline conditions without the requirement for additional Ca2+. However, BspPelA displays poor thermostability and is inactive after incubation at 50°C for only 30 min. Here, directed evolution was used to improve the thermostability of BspPelA for efficient and stable Degumming. After two rounds of error-prone PCR and screening of >12,000 mutants, 10 mutants with improved thermostability were obtained. Sequence analysis and site-directed mutagenesis revealed that single E124I, T178A, and S271G substitutions were responsible for improving thermostability. Structural and molecular dynamic simulation analysis indicated that the formation of a hydrophobic cluster and new H-bond networks was the key factor contributing to the improvement in thermostability with these three substitutions. The most thermostable combined mutant, EAET, exhibited a 140-fold increase in the t50 (time at which the enzyme loses 50% of its initial activity) value at 50°C, accompanied by an 84.3% decrease in activity compared with that of wild-type BspPelA, while the most advantageous combined mutant, EA, exhibited a 24-fold increase in the t50 value at 50°C, with a 23.3% increase in activity. Ramie Degumming with the EA mutant was more efficient than that with wild-type BspPelA. Collectively, our results suggest that the EA mutant, exhibiting remarkable improvements in thermostability and activity, has the potential for applications in ramie Degumming in the textile industry.
-
improving the thermoactivity and thermostability of pectate lyase from bacillus pumilus for ramie Degumming
Applied Microbiology and Biotechnology, 2015Co-Authors: Chaoning Liang, Cheng Zhou, Shuangyan TangAbstract:Thermostable alkaline pectate lyases can be potentially used for enzymatically Degumming ramie in an environmentally sustainable manner and as an alternative to the currently used chemical-based ramie Degumming processes. To assess its potential applications, pectate lyase from Bacillus pumilus (ATCC 7061) was cloned and expressed in Escherichia coli. Evolutionary strategies were applied to generate efficient ramie Degumming enzymes. Obtained from site-saturation mutagenesis and random mutagenesis, the best performing mutant enzyme M3 exhibited a 3.4-fold higher specific activity on substrate polygalacturonic acid, compared with the wild-type enzyme. Furthermore, the half-life of inactivation at 50 °C for M3 mutant extended to over 13 h. In contrast, the wild-type enzyme was completely inactivated in less than 10 min under the same conditions. An upward shift in the optimal reaction temperature of M3 mutant, to 75 °C, was observed, which was 10 °C higher than that of the wild-type enzyme. Kinetic parameter data revealed that the catalysis efficiency of M3 mutant was higher than that of the wild-type enzyme. Ramie Degumming with M3 mutant was also demonstrated to be more efficient than that with the wild-type enzyme. Collectively, our results suggest that the M3 mutant, with remarkable improvements in thermoactivity and thermostability, has potential applications for ramie Degumming in the textile industry.
-
the alkaline pectate lyase pel168 of bacillus subtilis heterologously expressed in pichia pastoris is more stable and efficient for Degumming ramie fiber
BMC Biotechnology, 2013Co-Authors: Chengjie Zhang, Cheng Zhou, Jia Yao, Liangwei Mao, Guimin ZhangAbstract:Background: The conventional Degumming process of ramie with alkaline treatment at high temperature causes severe environmental pollution. Pectate lyases can be used to remove pectin from ramie in a Degumming process with reduced environmental pollution and energy consumption. Pectate lyase PEL168 from Bacillus subtilis has been previously characterized and the protein structure was resolved. However, Bacillus is not a suitable host for pectate lyases during the Degumming process since most Bacillus produce cellulases endogenously with a detrimental effect to the fiber. Pichia pastoris, which does not express endogenous cellulases and has high secretion capability, will be an ideal host for the expression. No previous work was reported concerning the heterologous expression of pectate lyase PEL168 in P. pastoris with an aim for industrial application in ramie bio-Degumming. Results: The gene pel168 was expressed in P. pastoris in this study. The recombinant protein PEL168 in P. pastoris (PEL168P) showed two bands of 48.6 kDa and 51.4 kDa on SDS-PAGE whereas the enzyme expressed in E. coli (PEL168E) was the same as predicted with a band of 46 kDa. Deglycosylation digestion suggested that PEL168P was glycosylated. The optimum reaction temperature of the two PEL168s was 50°C, and the optimum pH 9.5. After preincubation at 60°C for 20 min, PEL168E completely lost its activity, whereas PEL168P kept 26% of the residual activity. PEL168P had a specific activity of 1320 U/mg with a Km of 0.09 mg/ml and a Vmax of 18.13 μmol/min. K + , Li + ,N i 2+ and Sr 2+ showed little or no inhibitory effect on PEL168P activity, and Ca 2+ enhanced enzyme activity by 38%. PEL168P can remove the pectin from ramie effectively in a Degumming process. A 1.5 fold increase of PEL168 enzyme expression in P. pastoris was achieved by further codon optimization. Conclusions: Pectate lyase PEL168 with an available protein structure can be heterologously expressed in P. pastoris. The characterized recombinant PEL168P can be used to remove pectin from ramie efficiently and the expression level of PEL168 in P. pastoris was increased markedly by codon optimization. Therefore, PEL168 is an ideal candidate for further optimization and engineering for bio-Degumming.
Zhong Lin Wang - One of the best experts on this subject based on the ideXlab platform.
-
high efficiency ramie fiber Degumming and self powered Degumming wastewater treatment using triboelectric nanogenerator
Nano Energy, 2016Co-Authors: Zhaoling Li, Chongwen Yu, Jun Chen, Jiajia Zhou, Li Zheng, Ken C Pradel, Zhong Lin WangAbstract:As one of the strongest and oldest natural fibers, ramie fiber has been widely used for fabric production for at least six thousand years. And Degumming is a critical procedure that has been developed to hold the ramie fiber’s shape, reduce wrinkling, and introduce a silky luster to the fabric appearance. Herein, we introduce a fundamentally new working principle into the field of ramie fiber Degumming by using the triboelectric effect. Resort to a water-driven triboelectric nanogenerator (WD-TENG), the ramie fibers Degumming efficiency was greatly enhanced with improved fiber quality, including both surface morphology and mechanical properties. Furthermore, it saves the chemicals usage in the traditional method, which makes it a green and practical approach to fully remove the noncellulosic compositions from ramie fibers. In addition, as a systematical study, the WD-TENG was further employed as a sustainable power source to electrochemically degrade the Degumming wastewater by recycling the kinetic energy from flowing wastewater in a self-powered manner. Under a fixed current output of 3.5 mA and voltage output of 10 V, the self-powered cleaning system was capable of cleaning up to 90% of the pollutants in the wastewater in 120 min. Given the compelling features of being self-powered, environmentally friendly, extremely cost-effective, good stability, high Degumming and degradation efficiency, the presented work renders an innovative approach for natural fiber extraction, and could be widely adopted as a green and innovative technology in textile industry.
-
high efficiency ramie fiber Degumming and self powered Degumming wastewater treatment using triboelectric nanogenerator
Nano Energy, 2016Co-Authors: Jun Chen, Jiajia Zhou, Li Zheng, Ken C Pradel, Xing Fan, Hengyu Guo, Zhen Wen, Minhsin Yeh, Zhong Lin WangAbstract:As one of the strongest and oldest natural fibers, ramie fiber has been widely used for fabric production for at least six thousand years. And Degumming is a critical procedure that has been developed to hold the ramie fiber’s shape, reduce wrinkling, and introduce a silky luster to the fabric appearance. Herein, we introduce a fundamentally new working principle into the field of ramie fiber Degumming by using the triboelectric effect. Resort to a water-driven triboelectric nanogenerator (WD-TENG), the ramie fibers Degumming efficiency was greatly enhanced with improved fiber quality, including both surface morphology and mechanical properties. Furthermore, it saves the chemicals usage in the traditional method, which makes it a green and practical approach to fully remove the noncellulosic compositions from ramie fibers. In addition, as a systematical study, the WD-TENG was further employed as a sustainable power source to electrochemically degrade the Degumming wastewater by recycling the kinetic energy from flowing wastewater in a self-powered manner. Under a fixed current output of 3.5 mA and voltage output of 10 V, the self-powered cleaning system was capable of cleaning up to 90% of the pollutants in the wastewater in 120 min. Given the compelling features of being self-powered, environmentally friendly, extremely cost-effective, good stability, high Degumming and degradation efficiency, the presented work renders an innovative approach for natural fiber extraction, and could be widely adopted as a green and innovative technology in textile industry.
Arthur J Ragauskas - One of the best experts on this subject based on the ideXlab platform.
-
utilization of deep eutectic solvent as a Degumming protocol for apocynum venetum bast
Cellulose, 2019Co-Authors: Yan Song, Yuanming Zhang, Wei Jiang, Arthur J RagauskasAbstract:Deep eutectic solvent (DES) pretreatment coupled with alkaline Degumming on Apocynum venetum bast was studied for developing an eco-friendly and effective Degumming method. A 1:2 mixture of choline chloride and urea was used in a microwave-assisted DES pretreatment optimized to 60 min and 110 °C. The impact of the deep eutectic solvent pretreatment on the properties of produced semi-degummed and refined dry fibers were assessed by examining the fiber chemical composition, surface microstructure, cellulose crystallinity, degree of polymerization, and fiber thermal properties. The combined DES and alkaline Degumming treatment effectively removed the gummy matter including hemicellulose and lignin from the A. venetum bast, providing a smooth and clean fiber surface. This combined DES and alkaline Degumming treatment also shows the ability to extract amorphous cellulose, leading to an increase of fiber crystallinity and a decrease of the average cellulose molecular weight. The thermal stability of the fibers was improved significantly after the Degumming treatment. The refined dry fibers produced by this combined DES-alkaline treatment exhibited comparable chemical and physical properties (e.g. residual gum content, fiber length, fiber fineness, breaking tenacity) compared with traditionally alkali Degumming method. These results revealed that DES is a practical and feasible pretreatment protocol for A. venetum bast Degumming.
-
a green Degumming process of ramie
Industrial Crops and Products, 2018Co-Authors: Wei Jiang, Yuanming Zhang, Yan Song, Arthur J Ragauskas, Shaoyang Liu, Haoxi Ben, Chengfeng Zhou, Guangting HanAbstract:Abstract Ramie provides the longest and strongest natural fiber in textile industry, but its traditional Degumming process is costly and requires a large amount of alkali, which causes serious environmental concerns. In the current work, a steam explosion (STEX) treatment followed by sodium percarbonate (SP) soak Degumming process was investigated. Microstructure, chemical composition and mechanical properties of the refined ramie fibers were comprehensively characterized. The residual gum content was below 5%, the fineness was higher than 1600 Nm (6.25 dtex), the breaking tenacity was 5.4 cN/dex, and the whiteness was above 50%. All of the properties met the requirements of Chinese national standard, and the breaking tenacity and whiteness were notably better than those of the fibers degummed traditionally. In addition, environmental impacts of the new Degumming process were evaluated. Only 50% chemicals were needed for the new process, and chemical oxygen demand (COD) of the waste reduced to 35% of the traditional method. Therefore, the new method was more environment-friendly and economically feasible. It has great potential for industry applications.
Li Zheng - One of the best experts on this subject based on the ideXlab platform.
-
high efficiency ramie fiber Degumming and self powered Degumming wastewater treatment using triboelectric nanogenerator
Nano Energy, 2016Co-Authors: Zhaoling Li, Chongwen Yu, Jun Chen, Jiajia Zhou, Li Zheng, Ken C Pradel, Zhong Lin WangAbstract:As one of the strongest and oldest natural fibers, ramie fiber has been widely used for fabric production for at least six thousand years. And Degumming is a critical procedure that has been developed to hold the ramie fiber’s shape, reduce wrinkling, and introduce a silky luster to the fabric appearance. Herein, we introduce a fundamentally new working principle into the field of ramie fiber Degumming by using the triboelectric effect. Resort to a water-driven triboelectric nanogenerator (WD-TENG), the ramie fibers Degumming efficiency was greatly enhanced with improved fiber quality, including both surface morphology and mechanical properties. Furthermore, it saves the chemicals usage in the traditional method, which makes it a green and practical approach to fully remove the noncellulosic compositions from ramie fibers. In addition, as a systematical study, the WD-TENG was further employed as a sustainable power source to electrochemically degrade the Degumming wastewater by recycling the kinetic energy from flowing wastewater in a self-powered manner. Under a fixed current output of 3.5 mA and voltage output of 10 V, the self-powered cleaning system was capable of cleaning up to 90% of the pollutants in the wastewater in 120 min. Given the compelling features of being self-powered, environmentally friendly, extremely cost-effective, good stability, high Degumming and degradation efficiency, the presented work renders an innovative approach for natural fiber extraction, and could be widely adopted as a green and innovative technology in textile industry.
-
high efficiency ramie fiber Degumming and self powered Degumming wastewater treatment using triboelectric nanogenerator
Nano Energy, 2016Co-Authors: Jun Chen, Jiajia Zhou, Li Zheng, Ken C Pradel, Xing Fan, Hengyu Guo, Zhen Wen, Minhsin Yeh, Zhong Lin WangAbstract:As one of the strongest and oldest natural fibers, ramie fiber has been widely used for fabric production for at least six thousand years. And Degumming is a critical procedure that has been developed to hold the ramie fiber’s shape, reduce wrinkling, and introduce a silky luster to the fabric appearance. Herein, we introduce a fundamentally new working principle into the field of ramie fiber Degumming by using the triboelectric effect. Resort to a water-driven triboelectric nanogenerator (WD-TENG), the ramie fibers Degumming efficiency was greatly enhanced with improved fiber quality, including both surface morphology and mechanical properties. Furthermore, it saves the chemicals usage in the traditional method, which makes it a green and practical approach to fully remove the noncellulosic compositions from ramie fibers. In addition, as a systematical study, the WD-TENG was further employed as a sustainable power source to electrochemically degrade the Degumming wastewater by recycling the kinetic energy from flowing wastewater in a self-powered manner. Under a fixed current output of 3.5 mA and voltage output of 10 V, the self-powered cleaning system was capable of cleaning up to 90% of the pollutants in the wastewater in 120 min. Given the compelling features of being self-powered, environmentally friendly, extremely cost-effective, good stability, high Degumming and degradation efficiency, the presented work renders an innovative approach for natural fiber extraction, and could be widely adopted as a green and innovative technology in textile industry.
David L Kaplan - One of the best experts on this subject based on the ideXlab platform.
-
silk Degumming time controls horseradish peroxidase catalyzed hydrogel properties
Biomaterials Science, 2020Co-Authors: Jugal Kishore Sahoo, Jaewon Choi, Onur Hasturk, Isabel Laubach, Marc L Descoteaux, Shreyas Mosurkal, Boyang Wang, Nina Zhang, David L KaplanAbstract:Hydrogels provide promising applications in tissue engineering and regenerative medicine, with silk fibroin (SF) offering biocompatibility, biodegradability and tunable mechanical properties. The molecular weight (MW) distribution of SF chains varies from ∼80 to 400 kDa depending on the extraction and purification process utilized to prepare the protein polymer. Here, we report a fundamental study on the effect of different silk Degumming (extraction) time (DT) on biomaterial properties of enzymatically crosslinked hydrogels, including secondary structure, mechanical stiffness, in vitro degradation, swelling/contraction, optical transparency and cell behaviour. The results indicate that DT plays a crucial role in determining material properties of the hydrogel; decrease in DT increases β-sheet (crystal) formation and mechanical stiffness while decreasing degradation rate and optical transparency. The findings on the relationships between properties of silk hydrogels and DT should facilitate the more rational design of silk-based hydrogel biomaterials to match properties needed for diverse purpose in biomedical engineering.
-
effect of processing on silk based biomaterials reproducibility and biocompatibility
Journal of Biomedical Materials Research Part B, 2011Co-Authors: Lindsay S Wray, Xiao Hu, Jabier Gallego, Irene Georgakoudi, Fiorenzo G Omenetto, Daniel Schmidt, David L KaplanAbstract:Silk fibroin has been successfully used as a biomaterial for tissue regeneration. In order to prepare silk fibroin biomaterials for human implantation a series of processing steps are required to purify the protein. Degumming to remove inflammatory sericin is a crucial step related to biocompatibility and variability in the material. Detailed characterization of silk fibroin Degumming is reported. The Degumming conditions significantly affected cell viability on the silk fibroin material and the ability to form three-dimensional porous scaffolds from the silk fibroin, but did not affect macrophage activation or β-sheet content in the materials formed. Methods are also provided to determine the content of residual sericin in silk fibroin solutions and to assess changes in silk fibroin molecular weight. Amino acid composition analysis was used to detect sericin residuals in silk solutions with a detection limit between 1.0% and 10% wt/wt, while fluorescence spectroscopy was used to reproducibly distinguish between silk samples with different molecular weights. Both methods are simple and require minimal sample volume, providing useful quality control tools for silk fibroin preparation processes.