Multi-omics and compositional analysis of bidirectional solid fermentation products from Cordyceps militaris and...

Ginsenosides, the main active compounds in American ginseng, have notable pharmacological effects, with rare ginsenosides offering higher bioavailability and bioactivity despite low abundance. Cordyceps militaris, an edible fungus, produces cordycepin and secretes enzymes like β-glucosidase that convert and enhance ginsenoside content. This study employed solid-state fermentation of American ginseng with C. militaris to investigate ginsenoside conversion and enrichment, alongside analyzing changes in cordycepin, gene expression, and metabolites during fermentation.

In this study, 30 % powdered ginseng was added to the C. militaris culture medium, with samples collected on different days for HPLC analysis of ginsenosides and cordycepin. Transcriptome sequencing and metabolomics analysis of C. militaris was performed on day 40 to investigate the pathways and mechanisms involved in the transformation and enrichment of these components.

HPLC analysis revealed that cordycepin levels in C. militaris cultured with American ginseng increased over time. Rare ginsenoside CK rose from undetectable to 11.81 mg, alongside significant increases in other rare ginsenosides. Mass spectrometry suggests ginsenoside CK is biosynthesized from Rb1 through intermediates Rd and F2. Transcriptome sequencing and metabolomics analysis revealed elevated expression of β-glucosidase and cordycepin synthesis genes. β-glucosidase is involved in carbohydrate and amino acid metabolism pathways, promoting substrate accumulation and providing energy for cordycepin synthesis.

This study demonstrates that co-culture of American ginseng with C. militaris enables bidirectional biotransformation: fungal enzymes convert ginsenosides into rare ginsenosides, while ginseng nutrients upregulate cordycepin biosynthesis. It offers a novel, eco-friendly approach for targeted transformation and enrichment of active ingredients.