Lactate dehydrogenase (LDH) is an enzyme found in nearly all living cells. It converts pyruvic acid to lactic acid as a subsequent step of glycerol metabolic pathway, thus LDH contributes to lactic acid biosynthesis from glycerol. LDH was reportedly active in rice (Oryza sativa) and corn (Zea mays) extract. This research aims to investigate the performance of LDH from rice extract and corn extract in pyruvic acid reduction to lactic acid. The effect of extraction temperature and extract concentration to lactic acid productivity was determined. Quantitative analysis of reaction product shows the presence of other products, which was predicted to be product of pyruvic acid oxidation and acetaldehyde. Activity of lactate dehydrogenase in pyruvic acid reduction was confirmed, suggesting a potential of further applications in lactic acid production.