Homoacetogens are a group of microorganisms with application potential to produce chemicals and biofuels by the bioconversion of synthesis gas. In this study, we collected waste activated sludge samples to screen homoacetogens by Hungate anaerobic technique, and studied the effect of pH on acetate and alcohol production from H2/CO2 gas. The mixed culture contained Clostridium ljungdahlii, Lysinibacillus fusiformis and Bacillus cereus. Acetate concentration achieved 31.69 mmol/L when the initial pH was 7. The mixed culture containing homoacetogen could converting H2/CO2 to acetate, which provides an efficient microbial resource for the bioconversion of synthesis gas.
Acetates ; chemistry ; Bacteria ; classification ; Biofuels ; Carbon Dioxide ; Hydrogen ; Sewage ; microbiology

A new type of instrument that called the rapid determination of carbon dioxide combining power without mercury is proposed. The performance of the instrument in accordance to the requirements in ISO15189 of laboratory accreditation has been evaluated. The results showed that, this instrument is safe, pollution-free, accurate and practical.
Carbon Dioxide ; analysis ; Clinical Chemistry Tests ; instrumentation ; Equipment Design

OBJECTIVETo develop a green and rapid method for extraction of lobetyolin from C. pilosula.

METHODExtraction of lobetyolin from C. pilosula with supercritical carbon dioxide in the presence of ethanol was studied. The effects of pressure, temperature, volume of cosolvent and extraction time on efficiency and their interactive relationships were discussed, based on central composite design and response surface methodology (RSM).

RESULTThe key effect factor was volume of cosolvent. The extraction yield of lobetyolin was 0.078 6 mg x g(-1) when C. pilosula (40-60 mesh) was extracted at 30 MPa, 60 degrees C and 2 L x min(-1) (as CO2 in normal pressure and temperature) for 100 minutes with supercritical CO2 and 1 mL x min(-1) ethanol as dynamic cosolvent.

CONCLUSIONThis result is better than that obtained from traditional method. Therefore, the optimized process is valuable for extraction of lobetyolin from C. pilosula.

Carbon Dioxide ; chemistry ; Chemical Fractionation ; methods ; Codonopsis ; chemistry ; Drugs, Chinese Herbal ; chemistry ; Ethanol ; chemistry ; Polyacetylenes ; chemistry

In order to optimize extraction process conditions of tannins from Geranium orientali-tibeticum by supercritical CO2, the content of tannins was determined by phosphomolybdium tungsten acid-casein reaction, with extraction pressure, extraction temper- ature and extraction time as factors, the content of tannins from extract of G. orientali-tibeticum as index, technology conditions were optimized by orthogonal test. Optimum technology conditions were as follows: extraction pressure was 25 MPa, extraction temperature was 50 °C, extracted 1.5 h. The content of tannins in extract was 12.91 mg x g(-1), extract rate was 3.67%. The method established could be used for assay the contents of tannin in G. orientali-tibeticum. The circulated extraction was an effective extraction process that was stable and feasible, and that provides a way of the extraction process conditions of tannin from G. orientali-tibeticum.
Carbon Dioxide ; chemistry ; Chemical Fractionation ; methods ; Drugs, Chinese Herbal ; chemistry ; Geranium ; chemistry ; Tannins ; isolation & purification

Most main oilfields in China have already entered a "double high" development stage (high water cut, high recovery degree). To further enhance oil recovery in reservoirs after polymer flooding (RAPFs), an efficient activator formulation for promoting metabolism of endogenous microorganism was studied by aerogenic experiments, physical simulation experiments, electron microscopy scanning and pyrophosphate sequencing. Results show that the activator could activate the endogenous microorganisms in the injected water and make the pressurized gas reach 2 MPa after 60 d static culture of the activator in a high pressure vessel. The oil recovery efficiency of natural core physical simulation flooding can be improved by more than 3.0% (OOIP) in RAPFs when injected 0.35 PV activator with 1.8% mass concentration, and a lot of growth and reproduction of activated endogenous microorganism in the core was observed by electron microscopy scanning. Field trial with 1 injector and 4 producers was carried out in the east of south II block of Sa Nan in December 2011. By monitoring four effective production wells, changes of carbon isotope δ13C (PDB) content of methane and carbon dioxide were -45 per thousand to -54 per thousand and 7 per thousand to 12 per thousand. Compared with east II of Sa Nan block, the oil amount increased by 35.9%, water cut stabled at 94%. The incremental oil was 5 957 t during the three and a half years, which provides an alternative approach for further improving oil recovery in similar reservoirs.
Carbon Dioxide ; chemistry ; Carbon Isotopes ; analysis ; China ; Diphosphates ; chemistry ; Methane ; chemistry ; Oil and Gas Fields ; microbiology ; Polymers ; Water ; Water Microbiology

Type, mode of affiliating, mechanism of action of entrainer in Supercritical CO2 on extraction of Chinese traditional and herbal drugs were briefly reviewed. Application of entrainer in Supercritical CO2 on extraction of flavones, terpenes, sterols, and saponins in Chinese traditional and herbal drugs were recommended in particular. Some problems and directions in research of entrainer in Supercritical CO2 on extraction of Chinese traditional and herbal drugs were shown in this paper.
Carbon Dioxide ; chemistry ; Chromatography, Supercritical Fluid ; methods ; Drugs, Chinese Herbal ; chemistry

The effects of pretreatment of supercritical carbon dioxide (SC-CO2) on the supramolecular structure of cellulose and the cellulase catalyzed reaction were investigated. The cellulase activity was not affected when it was treated with SC-CO2 at 10MPa and at 50 degrees C for 30 min. But when the cellulase was treated by SC-CO2 in the presence of cellulose, the catalytic activity of the cellulase was lost. The cellulose pretreated with or without cellulase under the same SC-CO2 condition was then hydrolyzed with tresh crude cellulase. The final reducing sugar yield from the hydrolysis of the cellulose pretreated with cellulase was higher than that of the cellulose pretreated without cellulase. It was also found that the improvement of the enzymolysis had a direct relevance with the amount of cellulase used during the SC-CO2 pretreatment. The moisture content of cellulose before SC-CO2 pretreatment had an obvious influence on the subsequent enzymolysis. When the moisture content of cellulose was 60% (W/W), the reducing sugar yield was higher than when the moisture content was over 100% (W/W). The FT-IR spectra showed that the structure of the cellulose pretreated with cellulase under the SC-CO2 condition was different from that of the cellulose pretreated without cellulase. In the presence of the enzyme, the strength of the hydrogen bonds and the I beta phase at 710cm(-1) in the crystalline cellulose was weakened. These results suggest that the change in the cellulose structure induced by the SC-CO2 treatment favous the subsequent enzymolysis.
Carbon Dioxide ; chemistry ; Cellulase ; chemistry ; metabolism ; Chromatography, Supercritical Fluid ; methods ; Spectroscopy, Fourier Transform Infrared

In order to improve its dispersion condition in dental composite resin and enhance its interaction with the matrix, single-walled carbon nanotubes(SWNTs) were refluxed and oxidized, then treated by APTE. Their outer surface were coated by nano-SiO2 particles using sol-gel process, then further treated by organosilanes ATES. IR and TEM were used to analyze modification results. TEM pictures showed nano-particles were on the surface of SWNTs; IR showed characteristic adsorbing bands of SiO2. Composite resin specimen with modified SWNTs was prepared and examined by TEM. SWNTs were detected in composite resin matrix among other inorganic fillers.
Composite Resins ; chemistry ; Dental Materials ; chemistry ; Humans ; Nanotubes, Carbon ; chemistry ; Resin Cements ; chemistry ; Silicon Dioxide ; chemistry ; Surface Properties ; Tensile Strength

OBJECTIVETo compare the ingredients of essential oils of Curcuma wenyujin extracted by supercritical-CO2 fluid extraction and by steam distillation.

METHODGC-MS was applied in this experiment.

RESULTThe ingredients and physical and chemical properties of essential oils of C. wenyujin extracted by supercritical-CO2 fluid extraction and by steam distillation are similar.

CONCLUSIONSupercritical-CO2 fluid extraction is better than steam distillation in extraction time, power consumption, recovery and purity.

Carbon Dioxide ; Chromatography, Supercritical Fluid ; methods ; Curcuma ; chemistry ; Oils, Volatile ; chemistry ; isolation & purification ; Plants, Medicinal ; chemistry ; Rhizome ; chemistry ; Volatilization

OBJECTIVETo optimize the extraction condtions in the modification of Rhizoma Cyperi, which had been extracted by the technique of supercritical CO2 extraction.

METHODThe semi-bionic extraction (SBE) conditions were optimized through homogeneous design while the extracts (< or = 1 000), the total area of HPLC and dry extracts were adopted as markers.

RESULTThe optimized SBE extraction conditions are the following: pH in first extraction was adjusted to 2.005 3. And then pH in second and third extraction adjusted to 6.508 2 and 8.945 6, time of the whole extracted process was 3.912 7 h.

CONCLUSIONCombine the faction of production,we make sure the conclusion is pH in first extraction was 2.00, pH in second and third extraction adjusted to 6.50 and 9.00, duration of run was 2.0 h, 1.0 h and 1.0 h, respectively.

Carbon Dioxide ; chemistry ; Chromatography, Supercritical Fluid ; methods ; Cyperus ; chemistry ; Drugs, Chinese Herbal ; chemistry ; Hydrogen-Ion Concentration ; Rhizome ; chemistry