Cloning and expression of rhl AB operon under the control of tac promoter in E. coli

Today, efforts go towards the replacement of chemical surfactants by natural biological biosurfactants (biosurfactant), as these materials are not carcinogenic and highly compatibile with the environment. One of the main classes of biosurfactants is rhamnose containing glycolipid biosurfactant (rhamnolipids). This type of biosurfactants can be applied in many industries such as oil industry, pharmaceutical industry, food industry and esc. In the present study, with elimination of regulatory elements of monorhamnolipid operon, the suitable construct was made and transformed to E. coli BL12 and E. coli DH5α competent cells. Then the production of monorhamnolipid in recombinant E. coli BL12 harboring pET 12a vector and mono and di-rhamnolipid biosurfactant in recombinant E. coli DH5α harboring pTrc 99A evaluated by CTAB plate and thin layer chromatography (TLC). The relative production of mono and dirhamnolipid biosurfactant was determined by oil spreading method. Finally, the efficiency of the extracted biosurfactant was verified by E12 method in different salinity and pH conditions.