Development of a Cost-Effective and Food-Grade Medium for Rice Cellular Agriculture

The global challenge of feeding a growing population while minimizing environmental impacts necessitates novel food production systems. Plant cellular agriculture offers a sustainable alternative for producing food ingredients; however, its commercial viability is hindered by the high costs and regulatory hurdles associated with conventional reagent-grade culture media. In this study, we developed a novel, cost-effective, and food-grade basal culture medium, FG-N6CI, for rice cellular agriculture. By replacing reagent-grade basal-medium components of the N6CI medium with food-grade alternatives, specifically by substituting chemical reagents with yeast extract, kelp powder, manganese yeast, and a boron supplement, we formulated a food-grade basal nutrient composition while retaining reagent-grade phytohormones. Rice (Oryza sativa L. 'Taichung 65') callus cultured on FG-N6CI medium exhibited significantly higher fresh weight (7.1 g) than the conventional N6CI medium (5.8 g) after 35 days (p < 0.05). Gene expression analysis showed no significant differences between the expression of OsHDA710 and OsTIR1, suggesting that FG-N6CI supports normal cellular proliferation and signaling similar to the standard medium. Economically, the cost of FG-N6CI medium was reduced by approximately 72% compared with that of the commercial reagent-grade mixture (219 JPY/L vs. 795 JPY/L). These results demonstrate that FG-N6CI is an economically competitive basal medium for scaling-up plant cellular agriculture.