naoA, encoding a nitroalkane oxidase that can catalyze toxic nitroalkanes to their corresponding aldehydes or ketones and hydrogen peroxide, was cloned from Streptomyces ansochromogenes, but its function related to the growth of Streptomyces is unknown. naoA was disrupted by the insertion of a kanamycin-resistance gene; the resulting strain can grow earlier than a wild-type strain under the same conditions. It was shown that naoA disruption accelerated growth of the naoA-disruption mutant, which could restore its phenotype and morphology as a wild-type strain by complementation of a single copy number of naoA inserted into the chromosome. The introduction of an extra copy of naoA into the wild-type strain resulted in delayed growth. The result suggested that naoA is an important gene related to the growth of S. ansochromogenes.