The present invention provides a method of producing optically active amino acids from 5-substituted hydantoin by isolating a hydantoinase gene and an N-carbamyl-L-amino acid hydrolase gene involved in an ability to convert 5-substituted hydantoin or N-carbamylamino acid into optically active amino acids from a microorganism of the genus Microbacterium having the above ability and by improving gene amplification and transcriptional and translational activities thereby preparing a recombinant wherein the amount of the desired enzymes produced is increased. The hydantoinase gene is, for example, a DNA encoding for a protein having a hydantoinase activity, which has the nucleotide sequence set forth in SEQ ID NO:1 in the Sequence. The N-carbamyl-L-amino acid hydrolase gene is, for example, a DNA encoding for a protein having an N-carbamyl-L-amino acid hydrolase activity, which has the nucleotide sequence set forth in SEQ ID NO:3 in the Sequence.