Analysis of the fungal population involved in Katsuobushi production

Naturally occurring fungi have been used in the traditional production of dried bonito, Katsuobushi, in Japan. In this study, we analyzed the fungal population present during Katsuobushi production. Amplicon sequence analysis of ITS1 indicated that Aspergillus spp. are predominant throughout the production process. In addition, culture-dependent analyzes identified three species Aspergillus chevalieri, Aspergillus montevidensis, and Aspergillus sydowii, based on sequencing of benA, caM, and rpb2 genes. A. chevalieri isolates were classified into teleomorphic and anamorphic strains based on morphological analysis. A. chevarieri was the dominant species throughout the production process, whereas A. montevidensis increased and A. sydowii decreased in abundance during Katsuobushi production. Our study will enhance the understanding of fungal species involved in traditional Katsuobushi production.