Regenesome, a Space Seed Holdings Group Company, Files Joint Patent Application for Koji Strain Selection
Regenesome Inc., a longevity-tech company in the Space Seed Holdings group, jointly filed a patent application with Kanazawa Institute of Technology and Oryze at the Japan Patent Office on August 31, 2026. The application describes a method for selecting koji mold strains for fermented sweeteners, including amazake and sweet koji (ama-koji), using DNA markers and enzyme-activity measurements.
Background
Koji mold (Aspergillus oryzae) is essential to Japanese fermented foods such as sake, miso, soy sauce and amazake. Amazake and other rice-koji sweeteners can be made without added sugar, because enzymes from koji break down rice starch into sugars.
Their sweetness and quality depend heavily on saccharifying enzymes, including alpha-amylase. However, the koji genome carries several alpha-amylase genes with more than 99% sequence identity, which makes the genes themselves hard to tell apart by ordinary PCR. The number of gene copies alone also does not determine how much enzyme a strain produces, so strain selection has relied on production experience or whole-genome sequencing.
The invention
The method analyzes the DNA regions surrounding the three alpha-amylase loci of koji mold. It combines PCR amplification patterns from those regions with measurements of saccharification-related enzyme activity after koji making. The procedure has four steps:
– Obtain PCR amplification patterns for the regions around the three loci from the genomic DNA of the test strains.
– Narrow down candidates to strains whose patterns differ from the reference strain (RIB40).
– Measure saccharification-related activity, such as alpha-amylase activity, in rice koji made with the candidate strains.
– Select strains with higher measured activity than the reference as koji molds for fermented sweeteners.
In the examples described in the application, the method selected a strain with about 2.2 times the alpha-amylase activity of the control strain, and rice koji made with that strain was used to produce amazake.
The amplification patterns can also be used to identify strains, for example to check the identity of strains in seed-koji lots. Besides the selection method, the application describes a strain identification method, a reagent set, a kit for distinguishing koji strains, and methods for producing rice koji and fermented sweeteners with the selected strains.
Features of the method
The method combines PCR patterns with enzyme-activity measurements, allowing candidate strains to be compared without whole-genome sequencing. The amplification patterns may also help check strain identity in seed-koji production. Whether the approach can be applied to other secreted enzymes, such as proteases and lipases, is a possibility for further study.
Application overview
– Title of invention: Method for selecting koji mold used in producing fermented sweeteners, method for identifying koji mold strains, reagent set, discrimination kit, method for producing rice koji, and method for producing fermented sweeteners
– Filing date: August 31, 2026
– Applicants: Kanazawa Institute of Technology; Oryze; Regenesome Inc.
– Inventors: Masayuki Machida and Motoaki Sano (Kanazawa Institute of Technology), Ai Kawahara (Oryze), Kengo Suzuki (Regenesome)
– International Patent Classification: C12Q 1/6895, C12Q 1/686, C12N 1/14
This announcement concerns the filing of a patent application and does not mean that a patent has been granted.
Next steps
Regenesome plans to work with Kanazawa Institute of Technology and Oryze on applying koji genome information to strain selection and fermented-food development.
About Regenesome Inc.
Regenesome is a longevity-tech company in the Space Seed Holdings group. It conducts research on aging and regenerative medicine using nanoparticles and runs a healthcare business under its own brand, Saisei Lab.
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About Space Seed Holdings Inc.
Space Seed Holdings is a space deep-tech venture builder whose mission is “Turning science fiction into nonfiction.” Its activities span investment, research and venture creation, and include the Fermentation and Longevity Fund program, which supports the practical use of fermentation and longevity technologies. Its long-term goal is to help develop the technologies needed for humans to live in space by 2040, working with partners across different fields.
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