Aerobic methylobacteria are capable of synthesizing auxins

Obligately and facultatively methylotrophic bacteria with different pathway s of C1 metabolism were found to be able to produce auxins, particularly in dole-3-acetic acid (IAA), in amounts of 3-100 mug/ml. Indole-3-pyruvic acid and indole-3-acetamide were detected only in methylobacteria with the seri ne pathway of C1 metabolism (Methylobacterium mesophilicum and Aminobacter aminovorans). The production of auxins by methylobacteria was stimulated by the addition of L-tryptophan to the growth medium and was inhibited by amm onium ions. The methylobacteria under study lacked tryptophan decarboxylase and tryptophan side-chain oxidase. At the same time, they were found to co ntain several aminotransferases. IAA is presumably synthesized by methyloba cteria through indole-3-pyruvic acid.