Improved cloning vectors for Bifidobacterium spp.

Abstract

The recombinant plasmids pDLI41, pDGA7 and pDC07 were constructed by cloning in pDG7, a vector based on Bifidobacterium longum replicon pMB1, the following heterologous genes: Pseudomonas fluorescens lipase, Bacillus licheniformis α-amylase and Streptomyces sp. cholesterol oxidase. The hybrid plasmids efficiently transformed Bifidobacterium belonging to five different species. A novel Escherichia coli-Bifidobacterium set of shuttle vectors based on the replicon pMBI (pLF5, pCLJ15, pSPEC1) featuring chloramphenicol, erythromycin and spectinomycin resistance genetic determinants as selection marker for bifidobacteria, was developed. The plasmid pTRE3, a derivative of pLF5, was the smallest (2-8 kb) Bifidobacterium vector, possessed a convenient multicloning site and presented high structural and segregational stability.