Abstract：Two recombinant plasmids pPM1 and pPM2, containing different -10 consensus sequences of tac promoter, were constructed by PCR amplification. The results of endonuclease digestion showed that tac promoter of plasmid pPM1 can be deleted in E. coli.. The total cell lysate of the host bacteria was extracted after cotransforming into Escherichia coli. HB101 respectively with pPM1+ pAX1, pPM2+ pAX1. The quantity of activator and 3α- HSD was tested by ELISA. The results indicated that -10 consence sepuence TATATT of tac promoter had higher transcriptional activity than TATGAT. The quantity of activator and 3α- HSD was pPM1＞pPM2＞pb. Meanwhile, recombinant plasmids were integrated into C. testosteroni chromosome through homologous recombination by electroporation respectively. Their degradation ability was determined by HPLC. It showed that gene engineered bacteria had higher degradation ability than cb7（C.T.+pb）and C.T..
