RIT 2214, A NEW BIOSYNTHETIC PENICILLIN PRODUCED BY A MUTANT OF CEPHALOSPORIUM ACREMONIUM

Abstract

A number of lysine-requiring auxotrophs of Ceplalosporium acremonium were investigated for incorporation of side-chain precursors and for accumulation of β-lactam compounds. One of the auxotrophs, Acremonium chrysogenum ATCC 20389, producing cephalosporin C and penicillin N only if grown in media supplemented with DL-α-amino-adipic acid (DL-α-AAA), was found to use L-S-carboxymethylcysteine (L-CMC) as a side-chain precursor for the synthesis of a new penicillin (RIT 2214). No corresponding cephalosporin was detected. The penicillin present in the culture filtrate, was concentrated by adsorption on activated carbon and successive column chromatography on Amberlite IRA-68 and Amberlite XAD-4. Final purification was achieved by cellulose column chromatography.
RIT 2214 was identified as 6-(D)-{[(2-amino-2-carboxy)-ethylthio]-acetamido}-penicillanic acid by spectral analysis, bioactivity spectrum, elucidation of side-chain structure and finally by semisynthesis. Its biological properties were also evaluated.