An in vitro gas production （GP） technique was used to investigate the effects of combining different doses of Salix babylonica extract （SB） with exogenous fibrolytic enzymes （EZ） based on xylanase （X） and cell...An in vitro gas production （GP） technique was used to investigate the effects of combining different doses of Salix babylonica extract （SB） with exogenous fibrolytic enzymes （EZ） based on xylanase （X） and cellulase （C）, or their mixture （XC; 1：1 v/v） on in vitro fermentation characteristics of a total mixed ration of corn silage and concentrate mixture （50：50, w/w） as substrate. Four levels of SB （0, 0.6, 1.2 and 1.8 mL g-1 dry matter （DM）） and four supplemental styles of EZ （1 μL g-1 DM; control （no enzymes）, X, C and XC （1：1, v/v） were used in a 4×4 factorial arrangement. In vitro GP （mL g-1 DM） were recorded at 2, 4, 6, 8, 10, 12, 24, 36, 48 and 72 h of incubation. After 72 h, the incubation process was stopped and supernatant pH was determined, and then filtered to determine dry matter degradability （DMD）. Fermentation parameters, such as the 24 h gas yield （GY24）, in vitro organic matter digestibility （OMD）, metabolizable energy （ME）, short chain fatty acid concentrations （SCFA）, and microbial crude protein production （MCP） were also estimated. Results indicated that there was a SBxEZ interaction （P〈0.0001） for the asymptotic gas production （b）, the rate of gas production （c）, GP from 6 to 72 h, GP2 （P=0.0095）, and GP4 （P=0.02）. The SB and different combination of enzymes supplementation influenced （P〈0.001） in vitro GP parameters after 12 h of incubation; the highest doses of SB （i.e., 1.8 mL g-1 DM）, in the absence of any EZ, quadratically increased （P〈0.05） the initial delay before GP begins （L） and GP at different incubation times, with lowering b （quadratic effect, P〈0.0001 ） and c （quadratic effect, P〈0.0001 ; linear effect, P=0.0018）. The GP was the lowest （P〈0.05） when the highest SB level was combined with cellulose. There were SBxEZ interactions （P〈0.001） for OMD, ME, the partitioning factor at 72 h of incubation （PF72）, GY24, SCFA, MCP （P=0.0143�展开更多
The production of cellulase in Bacillus amyloliquefaciens UNPDV-22 was optimized using response surface methodology （RSM）. Central composite design （CCD） was used to study the interactive effect of culture conditi...The production of cellulase in Bacillus amyloliquefaciens UNPDV-22 was optimized using response surface methodology （RSM）. Central composite design （CCD） was used to study the interactive effect of culture conditions （temperature, pH, and inoculum） on cellulase activity. Results suggested that temperature and pH all have significant impact on cellulase production. The use of RSM resulted in a 96% increase in the cellulase activity over the control of non-optimized basal medium. Optimum cellulase production of 13 U/mL was obtained at a temperature of 42.24 ℃, pH of 5.25, and inoculum size of 4.95% （v/v） in a fermentation medium containing wheat bran, soybean meal and malt dextrin as major nutritional factors.展开更多
Objective: The objective of the present study is to optimize cellulase production in five strains: (Pantoea dispersa MLTBY6 (MT646430.1);Pseudomonas aeruginosa MLTBM2 (MT646431.1);Pseudomonas monteilii MLTBC10 (MT6746...Objective: The objective of the present study is to optimize cellulase production in five strains: (Pantoea dispersa MLTBY6 (MT646430.1);Pseudomonas aeruginosa MLTBM2 (MT646431.1);Pseudomonas monteilii MLTBC10 (MT674682.1);Bacillus subtilis MLTBC5 (MT674681.1) and Lysinibacillus fusiformis MLTBB7 selected cellulase producers isolated from soils in Brazzaville, Republic of the Congo. Materials and Methods: The cellulolytic activity of the selected cellulase-producing strains was determined by transferring the strains to a petri dish containing CMC culture medium with the following composition: cellulose 1%, K<sub>2</sub>HPO<sub>4</sub> 0.2%, MgSO<sub>4</sub> 0.03%, peptone 1%, (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> 0.2% adjusted to a pH value of 7, previously poured and then frozen. The dishes were incubated in an oven at 37°C for 48 hours. The petri dishes were then flooded with 1% lugol for 15 minutes. A positive reading is indicated by the formation of a hydrolysis zone, the diameters of the hydrolysis zone were measured with a ruler. Strains with a broad lysis spectrum were selected. Optimisation of cellulase production by five bacterial strains isolated from the soil was done using the following factors: temperature and pH. Results: The production of cellulase showed that these strains showed a high production of cellulase at pH values between 5.6 and 9 with an optimum of pH = 8 and temperature values between 35°C and 40°C with an optimum at temperature t = 40°C. Of the carbon sources used, two sources, namely glucose and galactose, showed a high production of cellulase compared to the other carbon sources. However, the two nitrogen sources, ammonium sulphate and urea, were favourable for cellulase production by all five strains. Fe<sup>2+</sup>, CO<sup>2+</sup>, Zn<sup>2+</sup> ions are favourable for cellulase production by these strains, with a referendum for Fe<sup>2+</sup>. Conclusion: From these results, we conclude that the sources of carbon (glucose and galactose), nitrogen (ammonium sulpha展开更多
基金financial support from the IAEA, Vienna, Austria, Research Contract number MEX16307 within the D3.10.27 Coordinated Research Project
文摘An in vitro gas production （GP） technique was used to investigate the effects of combining different doses of Salix babylonica extract （SB） with exogenous fibrolytic enzymes （EZ） based on xylanase （X） and cellulase （C）, or their mixture （XC; 1：1 v/v） on in vitro fermentation characteristics of a total mixed ration of corn silage and concentrate mixture （50：50, w/w） as substrate. Four levels of SB （0, 0.6, 1.2 and 1.8 mL g-1 dry matter （DM）） and four supplemental styles of EZ （1 μL g-1 DM; control （no enzymes）, X, C and XC （1：1, v/v） were used in a 4×4 factorial arrangement. In vitro GP （mL g-1 DM） were recorded at 2, 4, 6, 8, 10, 12, 24, 36, 48 and 72 h of incubation. After 72 h, the incubation process was stopped and supernatant pH was determined, and then filtered to determine dry matter degradability （DMD）. Fermentation parameters, such as the 24 h gas yield （GY24）, in vitro organic matter digestibility （OMD）, metabolizable energy （ME）, short chain fatty acid concentrations （SCFA）, and microbial crude protein production （MCP） were also estimated. Results indicated that there was a SBxEZ interaction （P〈0.0001） for the asymptotic gas production （b）, the rate of gas production （c）, GP from 6 to 72 h, GP2 （P=0.0095）, and GP4 （P=0.02）. The SB and different combination of enzymes supplementation influenced （P〈0.001） in vitro GP parameters after 12 h of incubation; the highest doses of SB （i.e., 1.8 mL g-1 DM）, in the absence of any EZ, quadratically increased （P〈0.05） the initial delay before GP begins （L） and GP at different incubation times, with lowering b （quadratic effect, P〈0.0001 ） and c （quadratic effect, P〈0.0001 ; linear effect, P=0.0018）. The GP was the lowest （P〈0.05） when the highest SB level was combined with cellulose. There were SBxEZ interactions （P〈0.001） for OMD, ME, the partitioning factor at 72 h of incubation （PF72）, GY24, SCFA, MCP （P=0.0143�
文摘The production of cellulase in Bacillus amyloliquefaciens UNPDV-22 was optimized using response surface methodology （RSM）. Central composite design （CCD） was used to study the interactive effect of culture conditions （temperature, pH, and inoculum） on cellulase activity. Results suggested that temperature and pH all have significant impact on cellulase production. The use of RSM resulted in a 96% increase in the cellulase activity over the control of non-optimized basal medium. Optimum cellulase production of 13 U/mL was obtained at a temperature of 42.24 ℃, pH of 5.25, and inoculum size of 4.95% （v/v） in a fermentation medium containing wheat bran, soybean meal and malt dextrin as major nutritional factors.
文摘Objective: The objective of the present study is to optimize cellulase production in five strains: (Pantoea dispersa MLTBY6 (MT646430.1);Pseudomonas aeruginosa MLTBM2 (MT646431.1);Pseudomonas monteilii MLTBC10 (MT674682.1);Bacillus subtilis MLTBC5 (MT674681.1) and Lysinibacillus fusiformis MLTBB7 selected cellulase producers isolated from soils in Brazzaville, Republic of the Congo. Materials and Methods: The cellulolytic activity of the selected cellulase-producing strains was determined by transferring the strains to a petri dish containing CMC culture medium with the following composition: cellulose 1%, K<sub>2</sub>HPO<sub>4</sub> 0.2%, MgSO<sub>4</sub> 0.03%, peptone 1%, (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> 0.2% adjusted to a pH value of 7, previously poured and then frozen. The dishes were incubated in an oven at 37°C for 48 hours. The petri dishes were then flooded with 1% lugol for 15 minutes. A positive reading is indicated by the formation of a hydrolysis zone, the diameters of the hydrolysis zone were measured with a ruler. Strains with a broad lysis spectrum were selected. Optimisation of cellulase production by five bacterial strains isolated from the soil was done using the following factors: temperature and pH. Results: The production of cellulase showed that these strains showed a high production of cellulase at pH values between 5.6 and 9 with an optimum of pH = 8 and temperature values between 35°C and 40°C with an optimum at temperature t = 40°C. Of the carbon sources used, two sources, namely glucose and galactose, showed a high production of cellulase compared to the other carbon sources. However, the two nitrogen sources, ammonium sulphate and urea, were favourable for cellulase production by all five strains. Fe<sup>2+</sup>, CO<sup>2+</sup>, Zn<sup>2+</sup> ions are favourable for cellulase production by these strains, with a referendum for Fe<sup>2+</sup>. Conclusion: From these results, we conclude that the sources of carbon (glucose and galactose), nitrogen (ammonium sulpha
