title: Enhancement of enzyme activity and enantioselectivity via cultivation in nitrile metabolism by Rhodococcus sp. CGMCC 0497.
abstract: Racemic 2-phenylpropionitrile was resolved enantioselectively by nitrile-converting enzymes in cells of Rhodococcus sp. CGMCC 0497 to S-(+)-2-phenylpropionic acid and R-(-)-2-phenylpropionamide. By optimization of the culture conditions, great enhancement of enzyme activity and enantioselectivity was achieved. Furthermore, the relationship between cell-growth periodicity and enzyme accumulation was studied; the addition of inducer was delayed by 1 day and the reaction was further improved. This unusual strategy has almost never been reported with other nitrile-converting strains. The resulting culture broth, containing methacrylamide as the inducer, beef extract as the nitrogen source and glucose as the carbon source, with methacrylamide added 24 h later, seemed to be most suitable. S-(+)-2-Phenylpropionic acid and R-(-)-2-phenylpropionamide were produced with yields of 48% (enantiomeric excess, 96%) and 42% (enantiomeric excess, 97%) respectively with no nitrile left after 3 h, or with yields of 52% and 39% (enantiomeric excess, 93% and 99%) respectively after 6 h.
authors.affiliation: State Key Laboratory of Bio-organic & Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, People's Republic of China.
authors.forename: Zhong-Liu
authors.initials: ZL
authors.lastname: Wu
authors.forename: Zu-Yi
authors.initials: ZY
authors.lastname: Li
mesh_terms: D000097:Acetonitriles / Q000378:metabolism*; D000178:Acrylamides / Q000378:metabolism; D000577:Amides / Q000378:metabolism; D003470:Culture Media; D004789:Enzyme Activation; D005947:Glucose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D010507:Periodicity; D010666:Phenylpropionates / Q000378:metabolism; D012240:Rhodococcus / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000097:Acetonitriles; D000178:Acrylamides; D000577:Amides; D003470:Culture Media; D010666:Phenylpropionates; C083412:2-phenylpropionitrile; D005947:Glucose; C045985:methacrylamide