Abstract: The type-I polyketide synthase (PKS-I) gene screening system was applied to search potential producer of macrolide from 32 marine actinomycete strains.Based on DNA sequences alignment,the Actinoplanes sp.FIM060065 was acquired from 5 positive strains.One macrolide FW060065 was isolated and purified from the fermentation broth of the strain by pre-HPLC chromatography,and was identified to be tiacumicin B by UV,MS and NMR spectral date.Drug sensitivity test showed that FW060065 exhibited obvious antibacterial ability against gram-positive anaerobic bacteria such as Clostridium difficile,Peptostreptococcus anaerobius and Bifidobacterium bifidum .In this study,the tiacumicin-producing strain and its relevant metabolite was obtained by gene screening,which compelling evidence was provided for the relationship between PKS-I gene and macrolide.

Key words: macrolide, polyketide synthase, gene screening, metabolite, tiacumicin