Fermentation-assisted extraction of polysaccharides from the roots of Codonopsis pilosula using a selected Rhizopus arrhizus strain

Abstract

The roots of Codonopsis pilosula, also known as Codonopsis Radix, or Dangshen in the Chinese Pharmacopoeia, are plant parts commonly used for medicine and food. Polysaccharides are the major components found among the various bioactives in Codonopsis Radix and have attracted increasing attention in medicinal and functional foods in China. Currently, the methods reported for extracting Codonopsis Radix polysaccharides (CPs) still suffer from issues such as lengthy processing times, low yields, or high costs. In order to increase the extraction yield of CPs, a process of solid-state fermentation-assisted extraction using a fungus was developed in this study. Strain DS6 of Rhizopus arrhizus was isolated from a microbial enrichment culture on Codonopsis Radix. The yield of CPs was significantly increased after fermentation with DS6. Next, the operating conditions for the fermentation-assisted process of CP extraction were optimized. The yield of CPs extracted from the fermented Codonopsis Radix reached 24.7 % ± 0.43 %, representing a 46.2 % increase compared to the yield of CPs obtained from the unfermented Codonopsis Radix (16.9 % ± 0.35 %). The CPs extracted using the fermentation-assisted method retained their natural antioxidant activity. In conclusion, this process enhanced the yield of CPs and showed potential for industrial applications.