Construction of a novel shuttle vector for use in Brevibacterium flavum, an industrial amino acid producer.

Brevibacterium flavum has been developed to produce amino acids l-valine, l-lysine and l-threonine. However, there are not enough vectors available for the research on metabolic engineering in Brevibacterium flavum. Here we have constructed a shuttle expression vector pDXW-8 between Escherichia coli and B. flavum. The vector harbors an origin oriE for replicating in E. coli, a second origin oriC for replicating in B. flavum, a large multiple cloning site including 11 single restriction enzyme sites and suitable for cloning multiple genes or large DNA fragments, a tac promoter and a lacI(PF104) fragment which tightly controls the tac promoter. The applicability of pDXW-8 was confirmed by the expression of the vhb gene in B. flavum. The vector pDXW-8 will be very useful for research on metabolic engineering in corynebacteria.