Propionibacterium acidipropionici TISTR442 produced the highest amount of 5-aminolevulinic acid (ALA) when cultivated in medium supplemented with glycine at 18 g/l. ALA production correlated with ALA synthase activity, whereas ALA dehydratase activity was maintained at a low level. ALA yield reached 405 mg/l after prolonged cultivation for 1 month. (C) 2010, The Society for Biotechnology, Japan. All rights reserved.