Process of producing optically active cephalosporin analogs by enzyme selective deacylation

A process for producing optically active compound represented by the general formula (I) ##STR12## wherein R.sub.1 represents a hydrogen or a protective group of carboxylic acid, Hal represents a halogen atom, and the hydrogens at the 6- and 7-positions have cis configuration and salts thereof, which comprises reacting a compound represented by the formula (III) ##STR13## wherein R represents a substituted or unsubstituted, saturated or unsaturated six-membered carbocyclic or five-membered heterocyclic group, wherein the substituent represents a hydroxy group, a halogen atom, a nitro group or a methansulfonamide group, X represents a hydrogen, an amino group, a hydroxy group or a lower alkyl group, R.sub.1 and Hal have the same significance as defined above, and the hydrogens at the 6- and 7-positions have cis configuration with an enzyme capable of optically selective deacylation and thereafter recovering said optically active compound.