The discovery of biological enantioselectivity: Louis Pasteur and the fermentation of tartaric acid, 1857 - A review and analysis 150 yr later

Nearly a decade after discovering molecular chirality in 1848, Louis Pasteur changed research direction and began investigating fermentations. Conflicting explanations have been given for this switch to microbiology, but the evidence strongly suggests that Pasteur's appointment in 1854 to the University of Lille-an agricultural-industrial region where fermentation-based manufacturing was of great importance- and an appeal for help in 1856 by a local manufacturer experiencing problems in his beetroot-fermentation-based alcohol production played a significant role. Thus began, in late 1856, Pasteur's pioneering studies of lactic and alcoholic fermentations. In 1857, reportedly as a result of a laboratory mishap, he found that in incubations of ammonium (+/-)-tartrate with unidentified microorganisms (+)-tartaric acid was consumed with considerable preference over (-)-tartaric acid. In 1860, he demonstrated a similar enantioselectivity in the metabolism of tartaric acid by Penicillium glaucum, a common mold. Chance likely played a significant role both in Pasteur's shift to microbiology and his discovery of enantioselective tartrate fermentations, but he rejected pure serendipity as a significant factor in experimental science and in his own career. Pasteur's milestone discovery of biological enantioselectivity began the process that in the long run established the fundamental importance of molecular chirality in biology.