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Biotechnology and Applied Biochemistry (2002) 35, (61–67) (Printed in Great Britain)

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Enhancement of enzyme activity and enantioselectivity via cultivation in nitrile metabolism by Rhodococcus sp. CGMCC 0497

Zhong-Liu Wu and Zu-Yi Li¹

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

Key words: phenylpropionamide, phenylpropionic acid, phenylpropionitrile.

¹To whom correspondence should be addressed (e-mail lizy@pub.sioc.ac.cn).

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.

Received 4 September 2001/30 October 2001; accepted 23 November 2001

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