CHROMOSOME REARRANGEMENTS IN IMPROVED CEPHALOSPORIN C-PRODUCING STRAINS OF ACREMONIUM-CHRYSOGENUM

A number of A. chrysogenum strains from a lineage improved in cephalosporin C production were analyzed by contoured-clamped homogenous electric field gel electrophoreis (CHEF). Although antibiotic titre was increased across the lineage, chromosome rearrangements were only observed at two points in it. In one member of the lineage the chromosomal changes included those which altered the size of the chromosome on which the isopenicillin N synthetase gene (pcbC) was located. It is proposed that chromosome changes are a chance event in an industrial strain improvement programme.