Pyruvate metabolism in Lactobacillus brevis.

The pyruvate metabolism of LactobaciUus plantarum and Latobacillus arabino8su, which according to Bergey (1948) are identical organisms, has been studied by Rowatt (1951) and Nossal (1952). Both these homofermentative lactobacilli were shown to form 3-hydroxybutan-2-one (acetoin) as the main product of their pyruvate metabolism. No one appears to have studied the metabolism of pyruvate by any of the heterofermentative lactobacilli, of which Lactobacillus breisq is a typical example. This species frequently occurs in cheddar cheese, in the ripening of which it may play a significant part. It was considered of interest therefore to compare the pyruvate metabolism of L. brevis with that ofthe homofermentative species.