Aspergillus oryzae is one of the most important organisms in Japanese fermented food industry. Although it hardly produces secondary metabolites, related organisms are producers of diverse metabolites. A major objective of our project is to develop a system using A. oryzae to generate diverse metabolites. The factors affecting expression level of metabolic genes are being studied. To develop the system, novel vectors and host strains of A. oryzae have been constructed. W e have replaced promoter regions of some metabolic genes and successfully altered the level of some metabolite productions. Although it is well known that A.oryzae does not produce toxic metabolites, less attention has been paid to its non-toxic secondary metabolites. Genomic analysis revealed that A. oryzae possessed the orthologous gene cluster for penicillin production. The penicillin production was positively regulated by a global gene regulator required for transcriptional expression of the penicillin biosynthetic genes. Overexpression of the biosynthetic genes by a strong promoter yielded a greater than 100-fold increase in penicillin production. Transcriptional repression of a wide range of secondary metabolism genes in A. oryzae is a valuable characteristic for the production of a particular secondary metabolite with higher purity and safety. It appears that genetically engineered A. oryzae should be extremely useful as a cell factory for industrial production of beneficial secondary metabolites.
Full conference title:
7th International Aspergillus Meeting
- Asperfest 7 (2010)