젖산
Lactic acid is produced industrially by bacterial fermentation of carbohydrates, or by chemical synthesis from acetaldehyde. In 2009, lactic acid was produced predominantly (70–90%) by fermentation. Production of racemic lactic acid consisting of a 1:1 mixture of and stereoisomers, or of mixtures with up to 99.9% -lactic acid, is possible by microbial fermentation. Industrial scale production of -lactic acid by fermentation is possible, but much more challenging.