First paragraph (this article has no abstract) Antibiotics and antibiotics resistance genes have been traditionally used for the selection and maintenance of recombinant plasmids in hosts such as E. coli. Although a powerful selection tool, their use has been considered unacceptable in many areas of biotechnology by regulatory authorities. Indeed, there is much international scientific and regulatory focus on this issue [1]. For instance, the use of selection markers that confer resistance to antibiotics in vaccine plasmids may introduce the risk of transforming the patient's microflora and spread resistance genes. Moreover, in recombinant protein production for therapeutic use, the antibiotic must be eliminated from the final product. Another problem arises from the potential loss of selective pressure as a result of antibiotic degradation i.e. ampicillin can be degraded by β-lactamases in less than 30 minutes in high cell density cultures [2].Peer reviewed