Research advances in probiotic fermentation of Chinese herbal medicines.

Chinese herbal medicines (CHM) have been used to cure diseases for thousands of years. However, the bioactive ingredients of CHM are complex, and some CHM natural products cannot be directly absorbed by humans and animals. Moreover, the contents of most bioactive ingredients in CHM are low, and some natural products are toxic to humans and animals. Fermentation of CHM could enhance CHM bioactivities and decrease the potential toxicities. The compositions and functions of the microorganisms play essential roles in CHM fermentation, which can affect the fermentation metabolites and pharmaceutical activities of the final fermentation products. During CHM fermentation, probiotics not only increase the contents of bioactive natural products, but also are beneficial for the host gut microbiota and immune system. This review summarizes the advantages of fermentation of CHM using probiotics, fermentation techniques, probiotic strains, and future development for CHM fermentation. Cutting-edge microbiome and synthetic biology tools would harness microbial cell factories to produce large amounts of bioactive natural products derived from CHM with low-cost, which would help speed up modern CHM biomanufacturing.