The catalytic properties and thermodynamic kinetics of the endoglucanase from a marine Bacillus subtilis were analyzed. Optimum pH and temperature of the endoglucanase activity were 5.0 and 35 °C. The endoglucana...The catalytic properties and thermodynamic kinetics of the endoglucanase from a marine Bacillus subtilis were analyzed. Optimum pH and temperature of the endoglucanase activity were 5.0 and 35 °C. The endoglucanase activity, melt point temperature was 1.13 folds(247.02 U·ml^(-1)), 2.1 °C higher(39.2 °C) in 6% ethanol solution than that(218.60 U·ml^(-1)),(37.1 °C) in free ethanol. At 40 °C–55 °C, Gibbs free energy, ΔG, and the content ofα-helix was higher in 6% ethanol solution than that in ethanol free solution. The increasing of α-helix content led to higher activity and better thermostability in ethanol solution. The cold adapt ethanol tolerant endoglucanase was valuable for bioethanol product by simultaneous saccharification and fermentation process.展开更多
Background Lignocellulose biomass is the most abundant and renewable material in nature.The objectives of this study were to characterize two endoglucanases Trep Cel3 and Trep Cel4,and determine the effect of the comb...Background Lignocellulose biomass is the most abundant and renewable material in nature.The objectives of this study were to characterize two endoglucanases Trep Cel3 and Trep Cel4,and determine the effect of the combination of them(1.2 mg Trep Cel3,0.8 mg Trep Cel4)on in vitro rumen fermentation characteristics.In this study,three nature lignocellulosic substrates(rice straw,RS;wheat straw,WS;leymus chinensis,LC)were evaluated for their in vitro digestibility,gas,NH3-N and volatile fatty acid(VFA)production,and microbial protein(MCP)synthesis by adding enzymatic combination.Methods Two endoglucanases’genes were successfully expressed in Escherichia coli(E.coli)BL21(DE3),and enzymatic characteristics were further characterized.The combination of Trep Cel3 and Trep Cel4 was incubated with lignocellulosic substrates to evaluate its hydrolysis ability.Results The maximum enzymatic activity of Trep Cel3 was determined at p H 5.0 and 40℃,while Trep Cel4 was at p H 6.0 and 50℃.They were stable over the temperature range of 30 to 60℃,and active within the p H range of 4.0 to 9.0.The Trep Cel3 and Trep Cel4 had the highest activity in lichenan 436.9±8.30 and 377.6±6.80 U/mg,respectively.The combination of Trep Cel3 and Trep Cel4 exhibited the highest efficiency at the ratio of 60:40.Compared to maximum hydrolysis of Trep Cel3 or Trep Cel4 separately,this combination was shown to have a superior ability to maximize the saccharification yield from lignocellulosic substrates up to 188.4%for RS,236.7%for wheat straw WS,222.4%for LC and 131.1%for sugar beet pulp(SBP).Supplemental this combination enhanced the dry matter digestion(DMD),gas,NH3-N and VFA production,and MCP synthesis during in vitro rumen fermentation.Conclusions The Trep Cel3 and Trep Cel4 exhibited the synergistic relationship(60:40)and significantly increased the saccharification yield of lignocellulosic substrates.The combination of them stimulated in vitro rumen fermentation of lignocellulosic substrates.This combination has the potential to be a feed additive to improve agricultural residues utilization in ruminants.If possible,in the future,experiments in vivo should be carried out to fully evaluate its effect.展开更多
This study was conducted to evaluate the effectiveness of enzymes in purifying and reducing the degree of polymerization of cellulose for the production of dissolving pulp.Our goal was to determine the contributions o...This study was conducted to evaluate the effectiveness of enzymes in purifying and reducing the degree of polymerization of cellulose for the production of dissolving pulp.Our goal was to determine the contributions of xylanase(X)and endoglucanase(EG)in the treatment of pulp,specifically by quantifying the formation of soluble and insoluble reducing sugars using the dinitrosalycilic acid(DNS)test.Predominantly,the release of soluble reducing sugars(RSSol)was enhanced after xylanase treatment,while endoglucanase(EG)treatment led to changes in insoluble reducing sugars(RSIns).The maximum synergism was observed for RSIns when a high ratio of endoglucanase to xylanase(320EG:5X/g pulp)was used.The relative contribution of endoglucanase to RSins was determined to be 15.6%of the total reducing sugar.The viscosity of pulps treated with xylanase decreased only by 7%,whereas endoglucanase treatment significantly reduced viscosity by 45%.Modifications in the particle size were observed after pulp treatment with the combination of endoglucanase and xylanase.In summary,the DNS test is a rapid and effective method for evaluating the efficiency of enzyme treatments on pulps.The measurement of RSIns correlates with changes in pulp viscosity to different extents,providing valuable insights into the effectiveness of enzyme treatments.展开更多
The property of major cellulases from the guts of Anoplophora glabripennis larvae have been characterized. The optimal temperatures of both β 1,4 glucosidase (β glucosidase) and endo β 1,4 endoglucanase (...The property of major cellulases from the guts of Anoplophora glabripennis larvae have been characterized. The optimal temperatures of both β 1,4 glucosidase (β glucosidase) and endo β 1,4 endoglucanase (endoglucanase, Cx) are 40℃. The β glucosidase was optimally active at pH 4\^8, while the optimal activity of the endoglucanase occurred at pH 4 4 5 6 The endoglucanase was active with a wide range of pH and temperature, the levels of activity from 25℃ to 50℃ were more than 80%, and the activity remained 60% between pH 3 2 and pH 7 2. The endoglucanase exhibited higher thermal stability than β glucosidase. Both enzymes lose their activities by heat treatment at 60℃. Two isozymes of endoglucanase were detected in sodium carboxymethylcellulose polyacrymide gels (CMC gel) by chemical colorization, and purified by elution from the gel slices. The molecular weights of the two isozymes were estimated as 26kD and 39kD respectively. Moreover molecular characteristics of the two isozymes are currently underway.展开更多
基金Supported by the Science and Technology Research Project of Hubei Provicial Department of Education(B2017041)
文摘The catalytic properties and thermodynamic kinetics of the endoglucanase from a marine Bacillus subtilis were analyzed. Optimum pH and temperature of the endoglucanase activity were 5.0 and 35 °C. The endoglucanase activity, melt point temperature was 1.13 folds(247.02 U·ml^(-1)), 2.1 °C higher(39.2 °C) in 6% ethanol solution than that(218.60 U·ml^(-1)),(37.1 °C) in free ethanol. At 40 °C–55 °C, Gibbs free energy, ΔG, and the content ofα-helix was higher in 6% ethanol solution than that in ethanol free solution. The increasing of α-helix content led to higher activity and better thermostability in ethanol solution. The cold adapt ethanol tolerant endoglucanase was valuable for bioethanol product by simultaneous saccharification and fermentation process.
基金supported by the Carbon Peak&Carbon Neutralization Innovation Project of Jiangsu Province (BE2022309)Natural Science Foundation of China (32161143028,32061143034)the National Modern Agricultural Industry Technology System Guangxi Dairy Buffalo Innovation Team Project (nycytxgxcxtd-2021-21)。
文摘Background Lignocellulose biomass is the most abundant and renewable material in nature.The objectives of this study were to characterize two endoglucanases Trep Cel3 and Trep Cel4,and determine the effect of the combination of them(1.2 mg Trep Cel3,0.8 mg Trep Cel4)on in vitro rumen fermentation characteristics.In this study,three nature lignocellulosic substrates(rice straw,RS;wheat straw,WS;leymus chinensis,LC)were evaluated for their in vitro digestibility,gas,NH3-N and volatile fatty acid(VFA)production,and microbial protein(MCP)synthesis by adding enzymatic combination.Methods Two endoglucanases’genes were successfully expressed in Escherichia coli(E.coli)BL21(DE3),and enzymatic characteristics were further characterized.The combination of Trep Cel3 and Trep Cel4 was incubated with lignocellulosic substrates to evaluate its hydrolysis ability.Results The maximum enzymatic activity of Trep Cel3 was determined at p H 5.0 and 40℃,while Trep Cel4 was at p H 6.0 and 50℃.They were stable over the temperature range of 30 to 60℃,and active within the p H range of 4.0 to 9.0.The Trep Cel3 and Trep Cel4 had the highest activity in lichenan 436.9±8.30 and 377.6±6.80 U/mg,respectively.The combination of Trep Cel3 and Trep Cel4 exhibited the highest efficiency at the ratio of 60:40.Compared to maximum hydrolysis of Trep Cel3 or Trep Cel4 separately,this combination was shown to have a superior ability to maximize the saccharification yield from lignocellulosic substrates up to 188.4%for RS,236.7%for wheat straw WS,222.4%for LC and 131.1%for sugar beet pulp(SBP).Supplemental this combination enhanced the dry matter digestion(DMD),gas,NH3-N and VFA production,and MCP synthesis during in vitro rumen fermentation.Conclusions The Trep Cel3 and Trep Cel4 exhibited the synergistic relationship(60:40)and significantly increased the saccharification yield of lignocellulosic substrates.The combination of them stimulated in vitro rumen fermentation of lignocellulosic substrates.This combination has the potential to be a feed additive to improve agricultural residues utilization in ruminants.If possible,in the future,experiments in vivo should be carried out to fully evaluate its effect.
基金supported by CNPq(303416/2018-1)and FAPESP(2019/25867-3).
文摘This study was conducted to evaluate the effectiveness of enzymes in purifying and reducing the degree of polymerization of cellulose for the production of dissolving pulp.Our goal was to determine the contributions of xylanase(X)and endoglucanase(EG)in the treatment of pulp,specifically by quantifying the formation of soluble and insoluble reducing sugars using the dinitrosalycilic acid(DNS)test.Predominantly,the release of soluble reducing sugars(RSSol)was enhanced after xylanase treatment,while endoglucanase(EG)treatment led to changes in insoluble reducing sugars(RSIns).The maximum synergism was observed for RSIns when a high ratio of endoglucanase to xylanase(320EG:5X/g pulp)was used.The relative contribution of endoglucanase to RSins was determined to be 15.6%of the total reducing sugar.The viscosity of pulps treated with xylanase decreased only by 7%,whereas endoglucanase treatment significantly reduced viscosity by 45%.Modifications in the particle size were observed after pulp treatment with the combination of endoglucanase and xylanase.In summary,the DNS test is a rapid and effective method for evaluating the efficiency of enzyme treatments on pulps.The measurement of RSIns correlates with changes in pulp viscosity to different extents,providing valuable insights into the effectiveness of enzyme treatments.
文摘The property of major cellulases from the guts of Anoplophora glabripennis larvae have been characterized. The optimal temperatures of both β 1,4 glucosidase (β glucosidase) and endo β 1,4 endoglucanase (endoglucanase, Cx) are 40℃. The β glucosidase was optimally active at pH 4\^8, while the optimal activity of the endoglucanase occurred at pH 4 4 5 6 The endoglucanase was active with a wide range of pH and temperature, the levels of activity from 25℃ to 50℃ were more than 80%, and the activity remained 60% between pH 3 2 and pH 7 2. The endoglucanase exhibited higher thermal stability than β glucosidase. Both enzymes lose their activities by heat treatment at 60℃. Two isozymes of endoglucanase were detected in sodium carboxymethylcellulose polyacrymide gels (CMC gel) by chemical colorization, and purified by elution from the gel slices. The molecular weights of the two isozymes were estimated as 26kD and 39kD respectively. Moreover molecular characteristics of the two isozymes are currently underway.
