Japanese start-up Sunshiki secures pre-seed investment to scale seaweed-based cattle-feed additive

Sunshiki, a Japanese climate-tech start-up specialising in seaweed-based feed additives, has raised ¥80 million to expand production and advance commercialisation of a cattle feed supplement that significantly reduces methane emissions.

Japanese climate-tech start-up Sunshiki has raised ¥80 million in pre-seed funding to commercialise a cattle-feed additive made from kagikenori, or Asparagopsis taxiformis, a seaweed linked to 49-77% cuts in cattle methane. PR Times says the Shibuya-based Kochi University spin-out is led by Ryo Kubota; Venture Pitch Online says the cash will go on production capacity, commercialisation R&D and hiring. Market Screener reports the round was structured as convertible preferred stock and led by the Circular Economy Nature Positive No. 1 fund, co-managed by SBI Shinsei Corporate Investment and Sumitomo Mitsui Trust Investment, with Hazama Ando also participating.

The commercial question is supply, not proof of concept. Sunshiki says the bottleneck is low-cost, stable cultivation that preserves active compounds; it says it has already reached stable output in commercial-scale test tanks, including 7,000-litre land-based systems. On its website, the company says it is building capabilities from seed production to AI-based optimisation under a broader “Seaweed Platform Initiative”. That fits a wider Japanese push: AgNavigator reports JIRCAS began marine trials with Kaginowa in Yamakawa Bay in August, running to March 2028 under fisheries researcher Tatsuya Matsuda, while Norinchukin Bank says the related project is intended to raise fishermen’s incomes and restore blue-carbon seaweed beds as well as cut livestock emissions.