Catalyzes the interconversion of L-alanine and D-alanine. This organism is able to use both L- and D-alanine as a nitrogen source. May also prevent D-alanine from interfering with the use of L-alanine. L-alanine = D-alanine Amino-acid biosynthesis; D-alanine biosynthesis; D-alanine from L-alanine: step 1/1. No growth on D-alanine, however able to grow on L-alanine. Slower than wild-type growth on a mix of alanine isomers. Belongs to the alanine racemase family.