ABSTRACT
A novel reaction-enzymatic ammonolysis discovered in the mid of 1990s has been demonstrated to be a very promising alternative in the preparation of optically pure compounds. The effects of organic solvent, initial water activity, temperature and additives on lipase Novozym435-catalyzed enantioselective ammonolysis of racemic phenylglycine methyl ester were investigated systematically in this paper. Enzymatic reaction of ammonolysis showed higher activity and enantioselectivity than the corresponding reaction of hydrolysis and alcoholysis.
Subject(s)
Alcohols , Ammonia , Catalysis , Dimethylformamide , Pharmacology , Esters , Glycine , Metabolism , Hexoses , Pharmacology , Hydrolysis , Lipase , Metabolism , Organic Chemicals , Solvents , Surface-Active Agents , Pharmacology , Temperature , WaterABSTRACT
The effects of reaction media, water activity, temperature and pH on Novozym 435-catalyzed enantiose-lective ammonolysis of (?) -?-methylbenzyl acetate have been systematically explored. Novozym 435 showed high catalytic activity and enantioselectivity in hexane; the optimum temperature and the initial water activity were 25℃ and 0.33 respectively; The suitable reaction pH was in the range of 6.0 - 7.0.
ABSTRACT
Novozym 435 was selected from four lipases and two proteinase because of its high catalytic activity and enantiosectivity.For the ammonolysis of (?)-?-methylbenzyl acetate,The effect of ammonia sources,the concentration of enzyme and substrates on the reaction were further explored .under the optimum conditions of this study,after 6h reaction,with the enantiomeric excess of the remaining (-)-?-methylbenzyl acetate was found to be higher than 99%.
ABSTRACT
Enzymatic hydrolysis of nitrile was performed under mild conditions and afford high efficiency and selectivity,thus being highly potential for the synthesis of optically active carboxylic acids and their derivatives.The type of nitrile-hydrolyzing enzymes and hydrolysis reactions,reaction characteristics,factors influencing the hydrolysis and the prospect for its application to industrial production were reviewed in this paper.
ABSTRACT
Chlorella pyrenoidosa No.2 was screened from five species of microalga Chlorella sp. for its higher lipid yield. Effects of medium components and culture conditions on cell growth as well as lipid ac-cumulation of C. pyrenoidosa No.2 were investigated and the results showed that the optimum medium rec-ipe was 20.0 g/L glucose,0.08 g/L glycine,1.0 g/L K2HPO4?3H2O,0.4 g/L MgSO4?7H2O and 0.004 g/L FeSO4?7H2O. The optimum culture temperature,initial pH,shaking rate and light intensity were 28℃,6.0,130 r/min and 650 Lux,respectively. Biomass and lipid content increased from 3.73 g/L and 40.15% to 6.56 g/L and 59.90% when Chlorella pyrenoidosa No.2 was cultivated under the above optimal conditions for 7 days,with lipid yield raised by 162%. Chlorella pyrenoidosa No.2 could produce lipid with xylose as carbon source,and so is potential for lipid production from renewable materials such as lignocellulose. GC analysis demonstrated that the fatty acid composition of the lipid was similar to that of vegetable oil and its unsaturated fatty acid content reached around 71%,thus it is a promising material for biodiesel production.