Mycotoxin production and genetic analysis of Aspergillus niger and related species including the Kuro-Koji mold

Abstract

  The Kuro-Koji mold has been used in fermentation to produce a Japanese traditional spirit in southern part of Japan and the mold is very close to Aspergillus niger morphologically and physiologically. Then, they sometimes have been considered as synonym. Mycotoxin production and phylogenic relationships between them were studied. Some of the A. niger strains produced ochratoxins and most of the strains were producer of fumonisin B₂ whereas none of the Kuro-Koji mold strains synthesized the mycotoxins. Genetic analysis including cytochrome b DNA gene showed DNA types of the Kuro-Koji mold can be clearly distinguished from those of the mycotoxigenic strains of A. niger tested. Our study suggested that the Kuro-Koji mold as the producer of shouchu is a distinct genetic clade separated from A. niger although they are morphologically and physiologically very close.