抄録
Koji mold, Aspergillus oryzae, is a filamentous fungus used for the production of traditional fermented foods, such as sake, soy sauce, and soybean paste (miso), in Japan. A. oryzae secretes various hydrolytic enzymes including amylolytic and proteolytic enzymes, the most important enzymes for manufacturing Japanese fermented foods. These hydrolytic enzymes have been used in the food and pharmaceutical industries for a long time. Several transcription factors that control the expression of hydrolytic enzymes have been identified. Our recent studies revealed that the regulatory mechanism of amylolytic gene expression is controlled by two transcription factors. In addition to induction of expression, gene expression of glycoside hydrolytic enzymes is strongly repressed by carbon catabolite repression when glucose is present. Four factors (CreA, CreB, CreC, and CreD) have been identified as regulators of carbon catabolite repression in filamentous fungi. Our recent studies also revealed that the molecular mechanism of glucose-induced repression of amylolytic gene expression is mediated by these four factors. This review introduces the A. oryzae hydrolytic enzymes that are used for various industrial applications and the molecular mechanism of amylolytic gene expression regulation. In addition, this review also introduces the efforts to use A. oryzae as a host strain for production of heterologous proteins and secondary metabolites.
