Tdcbc/pcka gene-inactivated microorganism and method of producing l-threonine using the same

The present invention provide a microorganism comprising an inactivated chromosomal tdcBC gene and an inactivated chromosomal pckA gene, which has remarkably improved productivity of L-threonine. Also, the present invention provides a method of producing L-threonine using the microorganism. The microorganism is prepared by incorporating by a recombination technique an antibiotic resistance gene into a pckA gene on the chromosome of a bacterial strain containing an L-threonine degradation-associated operon gene, tdcBC, which is inactivated. The microorganism has the effect of preventing degradation and intracellular influx of L-threonine due to the inactivation of the tdcBC operon gene, and includes more activated pathways for L-threonine biosynthesis. Therefore, the microorganism is useful for mass production of L-threonine because of being capable of producing L-threonine in high levels and high yields even in the presence of high concentrations of glucose.