L―lactic acid producing genetically modified microorganisms and the method for preparing L―lactic acid using the same

摘要

PURPOSE: A PLA(polylactic acid) synthesized using a recombinant microorganism is provided to save production cost of PLA and to overcome instability by heat. CONSTITUTION: A method for producing a microorganism which produces L-type lactic acid with high optical purity comprises: a step of preparing a microorganism which simultaneously produces L-type and D-type lactic acid; and a step of knocking-out D-type lactic acid dehydrogenase(D-LDH) gene using pTOPOdelAP vector. The microorganism is Lactobacillus paracasei, Lactobacillus casei, or Lactobacillus johnsonii. A method for producing the L-type lactic acid comprises: a step of culturing a recombinant microorganism which produces L-type lactic acid with high purity; and a step of inoculating the cultured medium to a main culture medium; and a step of collecting the L-type lactic acid. [Reference numerals] (AA) D-type lactic acid productivity(%); (BB) D-type lactic acid production(g/L); (CC) Glucose concentration(g/L); (DD) Time; (EE) Lactic acid concentration(g/L);