Disclosed herein are glucose tolerant C.sub.2 carbon source-independent (GCSI) yeast strains having no detectable amount of pyruvate decarboxylase activity, wherein wild type yeast strains for the glucose tolerant C.sub.2 carbon source-independent yeast strains are Crabtree positive. Also disclosed are methods of selecting glucose tolerant C.sub.2 carbon source-dependent yeast strains, and methods of producing pyruvic acid or salts thereof using glucose tolerant C.sub.2 carbon source-independent yeast strain. Further disclosed herein are GCSI yeast strains having a genome that comprises an exogenous lactate dehydrogenase gene.