The feasibility of emploving non-ionic surfactant （Triton X-100） as an alternative and effective solventfor the microwave-assisted extraction of glycyrrhizic acid （GA） and liquiritin （LQ） from licorice root was ...The feasibility of emploving non-ionic surfactant （Triton X-100） as an alternative and effective solventfor the microwave-assisted extraction of glycyrrhizic acid （GA） and liquiritin （LQ） from licorice root was studied.The optimal extraction parameters based on the microwave-assisted micellar extraction technique were determined.Under the optimal conditions, i.e. 5% （by volume） Triton X-100, microwave-assisted extraction for 3--5min at 373K, the percentage extraction of active ingredients reached the highest value. The preconcentration tactor for GA and L＇Q （about 13.5） and the extraction efficiency for these two ingredients approached 100% showed the coupling of microwave-assisted extraction and cloud-point extraction could be employed as a new and. effective techniquefor the rapid extraction and preconcentration of pharrnacologically active ingredients from medicinal plants SUCh aslicorice root without disturbing chromatographic analysis.展开更多
Five bacterial strains, which are able to grow and to disintegratedibenzothiophene (DBT) and diben- zothiophene sulfone (DBTO_2) infossil fuels, are isolated. Analysis of products of DBT metabolizedby these strains sh...Five bacterial strains, which are able to grow and to disintegratedibenzothiophene (DBT) and diben- zothiophene sulfone (DBTO_2) infossil fuels, are isolated. Analysis of products of DBT metabolizedby these strains shows that different bacteria strains oxidized DBTby different pathways. The isolated strains R-6, $-16, $-9 and R-8can metabolize DBT to DBTO_2 and 3-hydroxybiphenyl (HBP), which areidentified as Bacillus brevis, Bacillus Sphaericus, Nocardiagloberula and Pseudomonas delafieldii respectively.展开更多
The kinetics of Candida rugosa lipase catalyzed esterification of racemic ibuprofen with n-butanol in isooctane was studied. The kinetic study was carried out with the addition of 0.1% and 2% (by volume) of water for ...The kinetics of Candida rugosa lipase catalyzed esterification of racemic ibuprofen with n-butanol in isooctane was studied. The kinetic study was carried out with the addition of 0.1% and 2% (by volume) of water for enzyme activation respectively when celite was added into isooctane for enzyme dispersion. The specific initial rate for S-ibuprofen can be fitted with the Ping Pong Bi Bi mechanism with dead-end competitive inhibition by the alcohol. The time courses of the enantioselective esterification of the two ibuprofen enantiomers with different initial substrate concentrations and water contents were simulated with a model in which both effects of enzyme inactivation by long term reaction and reversed hydrolytic reaction under high water content were taken into consideration.展开更多
基金Supported by the National Science Fund for Creative Research Groups （No.20221603）, the National Natural Science Foundation of China Key Project （No.20490200） and PetroChina.
文摘The feasibility of emploving non-ionic surfactant （Triton X-100） as an alternative and effective solventfor the microwave-assisted extraction of glycyrrhizic acid （GA） and liquiritin （LQ） from licorice root was studied.The optimal extraction parameters based on the microwave-assisted micellar extraction technique were determined.Under the optimal conditions, i.e. 5% （by volume） Triton X-100, microwave-assisted extraction for 3--5min at 373K, the percentage extraction of active ingredients reached the highest value. The preconcentration tactor for GA and L＇Q （about 13.5） and the extraction efficiency for these two ingredients approached 100% showed the coupling of microwave-assisted extraction and cloud-point extraction could be employed as a new and. effective techniquefor the rapid extraction and preconcentration of pharrnacologically active ingredients from medicinal plants SUCh aslicorice root without disturbing chromatographic analysis.
基金Supported by the special funds for major state basic research project (No.G2000048004) and SINOPEC.
文摘Five bacterial strains, which are able to grow and to disintegratedibenzothiophene (DBT) and diben- zothiophene sulfone (DBTO_2) infossil fuels, are isolated. Analysis of products of DBT metabolizedby these strains shows that different bacteria strains oxidized DBTby different pathways. The isolated strains R-6, $-16, $-9 and R-8can metabolize DBT to DBTO_2 and 3-hydroxybiphenyl (HBP), which areidentified as Bacillus brevis, Bacillus Sphaericus, Nocardiagloberula and Pseudomonas delafieldii respectively.
文摘The kinetics of Candida rugosa lipase catalyzed esterification of racemic ibuprofen with n-butanol in isooctane was studied. The kinetic study was carried out with the addition of 0.1% and 2% (by volume) of water for enzyme activation respectively when celite was added into isooctane for enzyme dispersion. The specific initial rate for S-ibuprofen can be fitted with the Ping Pong Bi Bi mechanism with dead-end competitive inhibition by the alcohol. The time courses of the enantioselective esterification of the two ibuprofen enantiomers with different initial substrate concentrations and water contents were simulated with a model in which both effects of enzyme inactivation by long term reaction and reversed hydrolytic reaction under high water content were taken into consideration.
