NOVEL RUMEN BACTERIA VARIANTS AND PROCESS FOR PREPARING SUCCINIC ACID EMPLOYING THE SAME. The present invention relates to novel rumen bacterial mutants resulted from the disruption of a lactate dehydrogenase gene (ldhA) and a pyruvate formate-lyase gene (pfl) (which are involved in the production of lactic acid, formic acid and acetic acid) from rumen bacteria; a novel bacterial mutant (Mannheimia sp. LPK7) having disruptions of a lactate dehydrogenase gene (ldhA), a pyruvate formate-lyase gene (plf), a phosphotransacetylase gene (pta), and a acetate kinase gene (ackA); a novel bacterial mutant (Mannheimia sp. LPK4) having disruptions of a lactate dehydrogenase gene (ldhA), a pyruvate formate-lyase gene (pfl) and a phosphoenolpyruvate carboxylase gene (ppc) involved in the immobilization of CO2 in a metabolic pathway of producing succinic acid(cas:110-15-6); and a method for producing succinic acid(cas:110-15-6), which is characterized by the culture of the above mutants in anaerobic conditions.

The inventive bacterial mutants have the property of producing succinic acid(cas:110-15-6) at high concentration while producing little or no organic acids, as compared to the prior wild-type strains of producing various organic acids. Thus, the inventive bacterial mutants are useful as strains for the industrial production of succinic acid(cas:110-15-6).