Gene regulation in Aspergillus oryzae promotes hyphal growth and flavor formation in soy sauce koji

Aspergillus oryzae 100-8 and the parental strain A. oryzae 3.042 are used in soy sauce fermentation in China. The growth rate of A. oryzae 100-8 is faster than A. oryzae 3.042, and the soy sauce flavors obtained with A. oryzae 100-8 fermentation are better than those obtained with A. oryzae 3.042. In this study, comparisons were made through biomass, reactive oxygen species (ROS) and gas chromatography-mass spectrometry (GC-MS) measurements, and the reasons for these differences were investigated through transcriptome and qRT-PCR analysis. The analysis indicated that several unique genes are closely associated with hyphal growth and flavor formation, as demonstrated by changes in the expression levels of these genes. These unique genes regulate hyphal growth and flavor formation in soy sauce koji fermentation.