Increasing Acid Tolerance of an Engineered Lactic Acid Bacterium Pediococcus acidilactici for L-Lactic Acid Production

Acid tolerance of the lactic acid bacterium (LAB) is crucially important for production free as a chemical monomer by simplified purification steps. This study conducts both metabolic modification and adaptive evolution approaches on increasing an engineered Pediococcus acidilactici strain. The overexpression genes encoding lactate dehydrogenase, recombinase, chaperone, glutathione ATPase did not show observable changes in tolerance. On other hand, low pH showed clear improvement. L-lactic generation cell viability adaptively evolved P. were doubled at up to 4.0 when wheat straw was used carbohydrate feedstock. However, further decrease value close pKa (3.86) led dramatic reduction generation. result shows partially successful approach improving acidilactici.