Abstract：Avermectin production of Streptomyces avermitilis could be stimulated by increasing the dosage of orfX gene. Integrative expression vector pWJ827 containing ermEp* and construction gene of orfX, was constructed based on pIJ8600. The recombinant strain BIB0827 was obtained by introducing pWJ827 into the industrial strain BIB9903 through intergeneric conjugal transfer. HPLC assays showed the avermectin production of BIB0827 reached 3350μg/mL, 1.5-fold increasing when compared with BIB9903. The characteristic of over producing strain BIB0827 was stable after ten rounds of non-selective growth, which could be applied in the industrial production of avermectin.
