The strains of C. acremonium used for the industrial production of cephalosporin C are all derived from a culture isolated by Brotzu in 1945 from a sewage outfall at Cagliari (Brotzu, 1948), however, the taxonomic position of this species is not clear. The name Cephalosporium acremonium was originally adopted but more recently the fungus has been reclassified by Gams (1971) who has suggested that it should be renamed Acremonium chrysogenum. The Brotzu strain together with a culture independently isolated from soil in India, Cephalosporium chrysogenum (Sukapure and Thirumalachar, 1963), are considered to be identical species by Gams. Mutant strains derived from both of these isolates have been used in these investigations. These cultures are certainly very similar in appearance on complete medium and both produce a characteristic yellow pigment. Mutant strains producing a red/pink mycelial pigment can also be obtained (Fig. 2.1).

Cephalosporium acremonium is an imperfect filamentous fungus which lacks a sexual reproductive cycle. The hyphae are organised as uninucleate segments and asexual hyaline spores (conidia) are produced on simple conidial structures. The conidia are abstricted successively and held together in a slime head (Fig. 2.2). Hyphal filaments can also differentiate into swollen, highly septate fragments (arthrospores) which may become multinucleate on ageing.

References

Brotzu, G. (1948). Richerche sudi un nuovo antibiotico. Lavori Dell'Instituto D'Igiene du Cagliari, 1-11.

Gams, W. (1971). Cephalosporium-artige Schimmelpilze (Hyphomycetes). Gustav Fischer Verlag, Stuttgart, Germany.

Sukapure, R.S. and Thirumalachar, M. J. (1963). Studies on Cephalosporium species from India - I. Mycologia, 55, 563-569.