Catalyzes the interconversion of L-alanine and D-alanine. L-alanine = D-alanine Optimum pH is 8.3. Optimum temperature is 30 degrees Celsius. Thermolabile and psychrotrophic. Shows catalytic activity even at 0 degree Celsius. Amino-acid biosynthesis; D-alanine biosynthesis; D-alanine from L-alanine: step 1/1. Homodimer. Belongs to the alanine racemase family.