Streptomyces lividans. Macrophotograph of a colony of the soil bacteria Streptomyces lividans, cultured in the laboratory. Various degrees of pigmentation occur, as seen here, produced by the bacterial growth itself & due to pigmented spores. Streptomyces species naturally produce a number of antibiotics, including streptomycin. As members of the group Actinomycetes, they share many characteristics with fungi. These bacteria grow in soil as a branching network of filaments known as a mycelium. They also produce aerial branches, containing chains of spores which rupture when mature and are dispersed on the wind.