SCREENING FOR NONPOLYENIC ANTIFUNGAL ANTIBIOTICS PRODUCED BY RARE ACTINOMYCETALES

Strains of Actinomycetales (286 in toto) belonging to thirteen genera other than Streptomyces were isolated from different ecosystems in the Algerian Sahara. Among these strains, 32 showed antibiotic activity a gainst at least one of the test organisms comprising four bacteria, tw o yeasts and several filamentous fungi, and twelve were antagonistic a gainst both bacteria and fungi. The characteristic UV spectra of activ e extracts revealed that six strains produced non-polyenic antifungal substances and four synthetized polyenic substances. One strain of Spi rillospora produced a pentaene antifungal substance. The only antibiot ic so far known to be produced by this genus is spirillomycin.