(19)

(11)

EP 0 557 352 A1

(12)

(43) Date of publication: 01.09.1993 Bulletin 1993/35 (21) Application number: 91919915.0 (22) Date of filing: 08.11.1991

(51) International Patent Classification (IPC):  A01H 1/ 00( . ) C12N 15/ 09( . ) C12N 15/ 82( . ) C12N 9/ 88( . ) C12N 15/ 60( . ) (86) International application number: PCT/GB1991/001972 (87) International publication number: WO 1992/008794 (29.05.1992 Gazette 1992/12)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 14.11.1990 GB 19900024728 (71) Applicant: IMPERIAL CHEMICAL INDUSTRIES PLC London SW1P 3JF (GB)

(72) Inventors: BRIGHT, Simon, William, Jonathan 24 Pound Lane Bucks SL7 2AY (GB) CHANG, Ming, Tang Ames, IA 50010 (US) EVANS, Ian, Jeffrey Berkshire RG5 4LR (GB) MACDONALD, Mairi, Jean Berkshire RG11 2SJ (GB) (74) Representative: Huskisson, Frank Mackie, et al  ICI Group Patents Services Dept. PO Box 6 Shire Park Bessemer Road Welwyn Garden City Herts, AL7 1HD Welwyn Garden City Herts, AL7 1HD (GB)