Development and Optimization of the Triterpenoid and Sterol Production Process with Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum Strain G0017 (Agaricomycetes), in Liquid Submerged Fermentation at Large Scale

Ganoderma lucidum mycelia are rich in active substances such as triterpenoids and sterols. However, reports on the development of effective submerged fermentation processes are lacking and the resulting total triterpene and sterol yield is still quite low. In this study, a new G. lucidum strain G0017 mycelium isolated by screening was studied in a 3-L fermenter to investigate the effect of aeration rate in liquid submerged fermentation production of triterpenoids and sterols. By fitting the specific mycelial growth rate and the specific production rate of the triterpenoid and sterol model, an effective multistage aeration rate control process for triterpenoid and sterol fermentation production was developed. This process was validated and proven in 3-L and 50-L fermenters. The resulting yields of triterpenoids and sterols were 3.34 and 3.46 g/L, respectively, which were 69.54% and 75.63% higher than the fixed aeration rate of 1.50 volume of air per volume of liquid per minute. This optimized fermentation production process conceivably could be applied to larger-scale industrial production and perhaps also to improve liquid submerged fermentation processes with relevant edible and medicinal mushrooms.