In a time where surface active agents are capable of reducing the energy of the bonds between water molecules by interacting with them to reduce surface tension, it would be unwise not to be able to generate these in ...In a time where surface active agents are capable of reducing the energy of the bonds between water molecules by interacting with them to reduce surface tension, it would be unwise not to be able to generate these in masses. Different Pseudomonas species were grown in MSP （minimal sulphate phosphate） media containing salts, glycerol and glucose. P. aeruginosa grown aerobically in the presence of glycerol as carbon source showed the highest emulsion percentage （81.48%）, most significant decrease in surface tension （20 mN/m） and rhamnose production of 2.86 mg/mL. However, in anaerobic conditions there was no emulsion, rhamnolipid production or decrease in surface tension. The rhamnolipids were molecularly characterized using ESI-MS （electrospray ionization-mass spectrometry）, P. aeruginosa CVCM 411 is able to produce mono-rhamnolipids and di-rhamnolipids, being rhamnolipid RhC10C12.1 the predominant monomer. The specific growth rate for isolates ofP. aeruginosa and P.fluorescens in MSP are 0.6732 ht and 0.2181 h^-1, respectively. In conclusion, the formation of rhamnolipids by P. aeruginosa is linked to its growth （depending on μ）, and its ability to generate about 35% of the μmax in the presence of glucose （carbon source） and glycerol （applied as pulses）.展开更多
A sensitive and robust on-line LC/MS method was developed for quantitative determination of linoleic acid,docosahexaenoic acid and docosanoic acid from edible oil samples.The oil samples were dissolved in chloroform-i...A sensitive and robust on-line LC/MS method was developed for quantitative determination of linoleic acid,docosahexaenoic acid and docosanoic acid from edible oil samples.The oil samples were dissolved in chloroform-isopropyl alcohol(20:80,v:v)solution and the three fatty acids were separated by HPLC with a C4 column using 10 mmol/L ammonium acetate-isopropyl alcohol-acetonitrile(20:40:40,v:v:v)mobile phase in isocratic elution.Electrospray ionization mass spectrometry with the selected ion recording monitoring was used to detect and quantify the fatty acid.The calibration curves were linear in the range of 10.00–5000 pg/mL for linoleic acid and docosanoic acid,and 1.000–500.0 pg/mL for docosahexaenoic acid.The limit of detection was 2.0 pg/mL for linoleic acid,3.0 pg/mL for docosanoic acid,and 0.20 pg/mL for docosahexaenoic acid.The results showed that the method described in this paper could be utilized for rapid determination of three fatty acids at picogram levels in edible oils.展开更多
文摘In a time where surface active agents are capable of reducing the energy of the bonds between water molecules by interacting with them to reduce surface tension, it would be unwise not to be able to generate these in masses. Different Pseudomonas species were grown in MSP （minimal sulphate phosphate） media containing salts, glycerol and glucose. P. aeruginosa grown aerobically in the presence of glycerol as carbon source showed the highest emulsion percentage （81.48%）, most significant decrease in surface tension （20 mN/m） and rhamnose production of 2.86 mg/mL. However, in anaerobic conditions there was no emulsion, rhamnolipid production or decrease in surface tension. The rhamnolipids were molecularly characterized using ESI-MS （electrospray ionization-mass spectrometry）, P. aeruginosa CVCM 411 is able to produce mono-rhamnolipids and di-rhamnolipids, being rhamnolipid RhC10C12.1 the predominant monomer. The specific growth rate for isolates ofP. aeruginosa and P.fluorescens in MSP are 0.6732 ht and 0.2181 h^-1, respectively. In conclusion, the formation of rhamnolipids by P. aeruginosa is linked to its growth （depending on μ）, and its ability to generate about 35% of the μmax in the presence of glucose （carbon source） and glycerol （applied as pulses）.
基金grateful to Ministry of Science and Technology of China under Contract(2012ZX09506001-010)the National High Technology Research and Development Program of China(2013AA092902)the National Natural Science Foundation of China(21172129)for financial support
文摘A sensitive and robust on-line LC/MS method was developed for quantitative determination of linoleic acid,docosahexaenoic acid and docosanoic acid from edible oil samples.The oil samples were dissolved in chloroform-isopropyl alcohol(20:80,v:v)solution and the three fatty acids were separated by HPLC with a C4 column using 10 mmol/L ammonium acetate-isopropyl alcohol-acetonitrile(20:40:40,v:v:v)mobile phase in isocratic elution.Electrospray ionization mass spectrometry with the selected ion recording monitoring was used to detect and quantify the fatty acid.The calibration curves were linear in the range of 10.00–5000 pg/mL for linoleic acid and docosanoic acid,and 1.000–500.0 pg/mL for docosahexaenoic acid.The limit of detection was 2.0 pg/mL for linoleic acid,3.0 pg/mL for docosanoic acid,and 0.20 pg/mL for docosahexaenoic acid.The results showed that the method described in this paper could be utilized for rapid determination of three fatty acids at picogram levels in edible oils.
