Copper‐dependent phenylalanine auxotrophy in Streptomyces spp. Strains were cultured on minimal agar medium without/with 10 µM CuSO4 and 0.05% phenylalanine. Colonies of the wild type and pheA mutant of S. coelicolor A3(2), wild‐type strains of S. griseus and S. avermitilis, and two environmental isolates are shown. Patches were photographed at 2 days.
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