5-Aminolevulinic acid (ALA) is an intermediate in the biosynthesis of tetrapyrroles. Its current production is expensive. We have developed a low-cost medium for Propionibacterium acidipropionici to produce extracellular ALA. When grown at 35 A degrees C on a medium containing 3 % (w/v) food-grade sodium lactate supplemented with 18 g glycine/l, 4.05 g succinate/l, 1.8 g glucose/l, pH 7, it produced ALA up to 7.7 g/l over 6 days. Plant-growth promoting activity assays showed that the ALA was biologically active.