PURPOSE:To provide a high-manifestation DNA sequence of biotin operon usable for the breeding of microbial strain having excellent biotin productivity. CONSTITUTION:The objective DNA sequence of a biotin operon of Escherichia coli contains at least one base pair varied from the wild type one at either the controlling region or near the bioB initiation codon. Escherichia coli transformed with a recombinant plasmid supporting the DNA sequence has high biotin productivity.
