Glycosylation of Ganoderic Acid G by Bacillus Glycosyltransferases

Ganoderma lucidum is a medicinal fungus abundant in triterpenoids, its primary bioactive components. Although numerous Ganoderma triterpenoids have already been identified, rare Ganoderma triterpenoid saponins were recently discovered. To create novel Ganoderma saponins, ganoderic acid G (GAG) was selected for biotransformation using four Bacillus glycosyltransferases (GTs) including BtGT_16345 from the Bacillus thuringiensis GA A07 strain and three GTs (BsGT110, BsUGT398, and BsUGT489) from the Bacillus subtilis ATCC 6633 strain. The results showed that BsUGT489 catalyzed the glycosylation of GAG to GAG-3-o-beta-glucoside, while BsGT110 catalyzed the glycosylation of GAG to GAG-26-o-beta-glucoside, which showed 54-fold and 97-fold greater aqueous solubility than that of GAG, respectively. To our knowledge, these two GAG saponins are new compounds. The glycosylation specificity of the four Bacillus GTs highlights the possibility of novel Ganoderma triterpenoid saponin production in the future.

Automated summary

Rare Ganoderma triterpenoid saponins were discovered and two novel Ganoderma saponins were successfully produced through enzymatic catalysis using four Bacillus enzymes, showing increased aqueous solubility. This study lays the foundation for the production of novel Ganoderma triterpenoid saponins in the future.