Novel lactobacillus strains and use thereof in fermentation process for L-lactic acid production

A method of making a bacterial strain that is capable of producing an increased yield or optical purity of L-lactic acid when compared to a starting strain, said method comprising:

• (a) inoculating bacterial growth medium with a starting strain selected from the group consisting of NRRL B-30568 (ADM B6-4), NRRL B-30569 (ADM DEC2-2B), NRRL B-30570 (ADM RP1A-4E), NRRL B-30571 (ADM RP2-1C), NRRL B-30572 (ADM RP3-1E), NRRL B-30573 (ADM RP4A-2C), NRRL B-30574 (ADM LC49.25), NRRL B-30575 (ADM LC54.62) and their respective mutants that produce L-lactic acid in at least 90% or greater optical purity, under conditions that allow the production of L-lactic acid by such strains;
• (b) incubating said medium thereby creating a population of identical bacteria;
• (c) harvesting the population during the mid-log phase of its exponential growth;
• (d) resuspending said population in a buffer and subjecting it to a mutagen;
• (e) isolating from said population individual mutant bacterial strains;
• (f) screening and isolating said mutant bacterial strains for improved yield or optical purity of L-lactic acid relative to said starting strain used to innoculate said bacterial growth medium in (a);
• (g) selecting said mutant bacterial strains having an improved yield or optical purity of L-lactic acid;
• and
• (h) optionally repeating (a) through (g) one or more times with said mutant bacterial strains having an improved yield or optical purity of L-lactic acid.

A method of identifying lactic acid producing bacteria which produce at least or greater than 90% optically pure L-lactic acid comprising:

• (a) collecting a sample from a biological material;
• (b) inoculating a bacterial growth medium with said sample and incubating the medium thereby propagating a mixed population of bacteria;
• (c) isolating from said mixed population of bacteria one or more individual bacterial strains;
• and
• (d) screening and identifying said one or more individual bacterial strains capable of producing at least or greater than about 90% optically pure L-lactic acid.