Antibiotic production by the cyanobacteriumNostoc muscorum

A broad spectrum antimicrobial antibiotic is produced byNostoc muscorum (Lancashire Polytechnic Culture Collection 23) during the post-exponential phase of growth. The antibiotic inhibits the growth of bacteria, notably multiple-resistantStaphylococcus aureus, and a biocide resistantPseudomonas aeruginosa: fungi such as the biodeteriogens,Cladosporium herbarum andHormoconis resinae and yeasts such asCandida albicans andC. pseudotropicalis. The antibiotic has an apparent molecular weight of 2000–3000 Daltons. Production appears to be dependent upon the limitation of one or more nutrients in the medium. author for correspondence