Adoption of a novel medium for the industrial (3000 L) production of Serendipita indica employing a nutrient limitation strategy using insoluble carbon and phosphate sources.

The use of the endophytic fungus Serendipita indica has rapidly increased due to its wide range of host species, ability to foster plant-growth, and ability to confer tolerance to a number of stresses. However, its industrial-scale production is still in its infancy due to its low-biomass yield and prolonged cultivation time. Thus far, Hill-Kafer medium has traditionally been used for S. indica cultivation, resulting in lower yields and excessively long incubation times. Here, we adopted a simple insoluble carbon and phosphate input medium for rapidly generating high biomass. We developed and optimized the SIF1 medium, achieving maximum biomass production (424.5 ± 1.9 g/L), significantly outperforming Hill-Kafer medium. Statistical optimization of SIF1 identified optimal levels (15 g/L oats, 7.5 g/L tricalcium phosphate, 95-hr incubation). Validated results in the laboratory (FUS-10 L: 484.4 ± 4.7), pilot (300 L: 496.5 ± 7 g/L), and industrial (3000L: 492.4 ± 7.1 g/L) bioreactors proved the efficacy of SIF1. Compared to Hill-Kafer (54.8 ± 3.7 g/L), SIF1 showed nine-fold higher biomass productivity and reduced cultivation time by approximately 6 days. Based on our findings, it appears that SF1 will be a highly efficient medium for producing S. indica on an industrial scale and expanding its use.

One-sentence summary: This study presents a rapid industrial production strategy for the beneficial fungus Serendipita indica, providing a scalable solution for wider applications and contributing to global food security and environmental sustainability.