Molecular Analysis of AsamyR Gene Encoding Transcriptional Factor for Amylolytic Gene from Shoyu Koji Mold, Aspergillus sojae KBN1340

The gene, designated AsamyR, encoding a transcriptional activator involved in amylolytic gene expression was isolated from a shoyu koji mold, Aspergillus sojae KEN1340, and characterized. The structural gene comprised 1,951 bp with 2 introns. AsAmyR consisted of 595 amino acid residues possessing a high degree of sequence identity with other Aspergillus AmyRs. The AsamyR gene disruptant showed significantly restricted growth on starch agar plates and produced no detectable alpha-amylase production in SP medium. The multicopy AsamyR strain exhibited approximately two-fold higher amylase activity when compared to that of the control strain, but the increased rate of the amylase activity was not as high as the copy number of the integrated AsamyR gene.