Construction of Streptomyces lividans SBT5 as an efficient heterologous expression host

Three gene clusters controlling the biosynthesis of the antibiotics actinorhodin(ACT),undecylprodigiosin(RED)and calcium-dependent antibiotic(CDA)were sequentially knockouted by gene replacements from the chromosome of Streptomyces lividans TK24to derive SBT5.In SBT5,the global regulatory genes afsRScla fromStreptomyces clavuligerus was integrated in the place of the cda gene cluster.The act gene cluster fromStreptomyces coelicolor was introduced into SBT5to test its capability of expressing secondary gene cluster.The resulting SBT5exconjugants overproduced ACT comparing with wild-type strains harboring double copies of the act gene cluster.SBT5is an efficient host with a clean secondary metabolism background suitable for heterologously expressing and screening secondary metabolic gene clusters.