Commonly used KEC value (0.45) of the fumigation-extraction (FE) method was obtained on the basis of temperate neutral soils. To ascertain its applicability to acidic red soils widespread in southern China and other s...Commonly used KEC value (0.45) of the fumigation-extraction (FE) method was obtained on the basis of temperate neutral soils. To ascertain its applicability to acidic red soils widespread in southern China and other subtropical regions, the KEC value was investigated based on 8 acidic red soils by in situ labelling of native soil microorganisms using 14C-labelled glucose. Realistic KEC value for red soils could be obtained by in situ 14C-labelling as long as an incubation period of 72 h is adopted after addition of 14C glucose to soil. The single KEC values for the eight red soils ranged from 0.27 to 0.35 and averaged 0.31. Lower KEC value obtained in red soils probably resulted from different soil quality, compared with other types of soil,which causes possible changes in microbial community structure and extractability of cellular component.Microbial biomass C contents of the eight red soils measured using a unique and constant KEC value of 0.45 decreased by 22.2%～40% in comparison to those using variable KEC values. The results suggest that microbial biomass C would be significantly underestimated using the present KEC value and a calibration of the KEC value is necessary for red soils.展开更多
A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, ...A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, propionate, oxalate, succinate, glutarate, fluoride, chloride and sulfate were separated and determined in 33 min. The samples were pretreated with solid-phase extraction, which has high selectivity for removing a large number of metallic ions in the Bayer liquors, and filtered with a 0.45 μm filter membrane before being injected into the ion chromatographic system. The separation of six organic acids and three inorganic anions was achieved on an IonPac AS11-HC column with KOH as the eluent, and the detection was performed by a conductivity detection mode. No interference is found in the presence of fluorate, chlorate and sulphate when organic acids are determined. The calibration graphs of peak area for all the analytes are linear over a wide range. The relative standard derivation of the peak area of analytes is less than 2.14%. Under optimum conditions the detection ranges from 0.2 to 100.0 mg/L. The average recoveries of the added standards are between 94.3% and 102.8%.展开更多
Using lignite samples, selected from Zhaotong basin, Yunnan province, China, as the parent source, simulating experiments of lignite biogas were conducted with 0.1% methanol, 5 mg/L yeast extract and 0.2 mol/L sodium ...Using lignite samples, selected from Zhaotong basin, Yunnan province, China, as the parent source, simulating experiments of lignite biogas were conducted with 0.1% methanol, 5 mg/L yeast extract and 0.2 mol/L sodium acetate solutions as the exogenous substance respectively. Variation characteristics of gas production, gas composition, VFA content and activity of coenzyme 1：42o in the simulated process were analyzed to discuss the influence of different substrates on lignite biogas generation. The results show that 0.1% methanol and 5 mg/L yeast extract solutions increase VFA contents in the biogas generation system （p 〈 0.05） and inhibit coenzyme F420 and methanogen activities significantly, so they decrease both gas amounts （p 〈 0.05） and CH4 contents （p 〈 0.05）. 0.2 mol/L sodium acetate solution activates coenzyme F42o and methanogen activities and improves the efficiency of enzymatic reaction, so the gas quantity （p 〈 0.05） and the CH4 content （p 〈 0.01） increase significantly. Therefore, sodium acetate can be one kind of good exogenous substance for the generation of lignite biogenic gas.展开更多
The present study was designed to establish and optimize a new method for extracting chlorogenic acid and cynaroside from Lonicera japonica Thunb. through orthogonal experimental designl. A new ultrahigh pressure extr...The present study was designed to establish and optimize a new method for extracting chlorogenic acid and cynaroside from Lonicera japonica Thunb. through orthogonal experimental designl. A new ultrahigh pressure extraction （UPE） technology was applied to extract chlorogenic acid and cynaroside from L. japonica. The influential factors, including solvent type, ethanol concentration, extraction pressure, time, and temperature, and the solid/liquid ratio, have been studied to optimize the extraction process, The optimal conditions for the UPE were developed by quantitative analysis of the extraction products by HPLC-DAD in comparison with standard samples. In addition, the microstructures of the medicinal materials before and after extraction were studied by scanning electron microscopy （SEM）. Furthermore, the extraction efficiency of different extraction methods and the 2, 2-diphenyl-1-picrylhydrazyl （DPPH） radical scavenging activities of the extracts were investigated. The optimal conditions for extracting chlorogenic acid and cynaroside were as follows： ethanol concentration, 60%; extraction pressure, 400 MPa; extraction time, 2 rain; extraction temperature, 30 ℃; and the solid/liquid ratio, 1 ： 50. Under these conditions, the yields of chlorogenic acid and cynaroside were raised to 4.863% and 0.080%, respectively. Compared with other extraction methods, such as heat reflux extraction （HRE）, ultrasonic extraction （UE）, and Sohxlet extraction （SE）, the UPE method showed several advantages, including higher extraction yield, shorter extraction time, lower energy consumption, and higher purity of the extracts. This study could help better utilize L. japonica flower buds as a readily accessible source of natural antioxidants in food and pharmaceutical industries.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 49571042) and the National Outstanding Youth Foundati
文摘Commonly used KEC value (0.45) of the fumigation-extraction (FE) method was obtained on the basis of temperate neutral soils. To ascertain its applicability to acidic red soils widespread in southern China and other subtropical regions, the KEC value was investigated based on 8 acidic red soils by in situ labelling of native soil microorganisms using 14C-labelled glucose. Realistic KEC value for red soils could be obtained by in situ 14C-labelling as long as an incubation period of 72 h is adopted after addition of 14C glucose to soil. The single KEC values for the eight red soils ranged from 0.27 to 0.35 and averaged 0.31. Lower KEC value obtained in red soils probably resulted from different soil quality, compared with other types of soil,which causes possible changes in microbial community structure and extractability of cellular component.Microbial biomass C contents of the eight red soils measured using a unique and constant KEC value of 0.45 decreased by 22.2%～40% in comparison to those using variable KEC values. The results suggest that microbial biomass C would be significantly underestimated using the present KEC value and a calibration of the KEC value is necessary for red soils.
基金Project(2005CB623702) supported by the National Key Basic Research Program of China
文摘A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, propionate, oxalate, succinate, glutarate, fluoride, chloride and sulfate were separated and determined in 33 min. The samples were pretreated with solid-phase extraction, which has high selectivity for removing a large number of metallic ions in the Bayer liquors, and filtered with a 0.45 μm filter membrane before being injected into the ion chromatographic system. The separation of six organic acids and three inorganic anions was achieved on an IonPac AS11-HC column with KOH as the eluent, and the detection was performed by a conductivity detection mode. No interference is found in the presence of fluorate, chlorate and sulphate when organic acids are determined. The calibration graphs of peak area for all the analytes are linear over a wide range. The relative standard derivation of the peak area of analytes is less than 2.14%. Under optimum conditions the detection ranges from 0.2 to 100.0 mg/L. The average recoveries of the added standards are between 94.3% and 102.8%.
基金supported by the National Natural Science Key Foundation of China (Nos. 41202119 and 41272177)the National Natural Science Key Foundation of China (No. 41202237)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Using lignite samples, selected from Zhaotong basin, Yunnan province, China, as the parent source, simulating experiments of lignite biogas were conducted with 0.1% methanol, 5 mg/L yeast extract and 0.2 mol/L sodium acetate solutions as the exogenous substance respectively. Variation characteristics of gas production, gas composition, VFA content and activity of coenzyme 1：42o in the simulated process were analyzed to discuss the influence of different substrates on lignite biogas generation. The results show that 0.1% methanol and 5 mg/L yeast extract solutions increase VFA contents in the biogas generation system （p 〈 0.05） and inhibit coenzyme F420 and methanogen activities significantly, so they decrease both gas amounts （p 〈 0.05） and CH4 contents （p 〈 0.05）. 0.2 mol/L sodium acetate solution activates coenzyme F42o and methanogen activities and improves the efficiency of enzymatic reaction, so the gas quantity （p 〈 0.05） and the CH4 content （p 〈 0.01） increase significantly. Therefore, sodium acetate can be one kind of good exogenous substance for the generation of lignite biogenic gas.
基金supported by the PAPD(A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions)
文摘The present study was designed to establish and optimize a new method for extracting chlorogenic acid and cynaroside from Lonicera japonica Thunb. through orthogonal experimental designl. A new ultrahigh pressure extraction （UPE） technology was applied to extract chlorogenic acid and cynaroside from L. japonica. The influential factors, including solvent type, ethanol concentration, extraction pressure, time, and temperature, and the solid/liquid ratio, have been studied to optimize the extraction process, The optimal conditions for the UPE were developed by quantitative analysis of the extraction products by HPLC-DAD in comparison with standard samples. In addition, the microstructures of the medicinal materials before and after extraction were studied by scanning electron microscopy （SEM）. Furthermore, the extraction efficiency of different extraction methods and the 2, 2-diphenyl-1-picrylhydrazyl （DPPH） radical scavenging activities of the extracts were investigated. The optimal conditions for extracting chlorogenic acid and cynaroside were as follows： ethanol concentration, 60%; extraction pressure, 400 MPa; extraction time, 2 rain; extraction temperature, 30 ℃; and the solid/liquid ratio, 1 ： 50. Under these conditions, the yields of chlorogenic acid and cynaroside were raised to 4.863% and 0.080%, respectively. Compared with other extraction methods, such as heat reflux extraction （HRE）, ultrasonic extraction （UE）, and Sohxlet extraction （SE）, the UPE method showed several advantages, including higher extraction yield, shorter extraction time, lower energy consumption, and higher purity of the extracts. This study could help better utilize L. japonica flower buds as a readily accessible source of natural antioxidants in food and pharmaceutical industries.
