Culture pH affects exopolysaccharide production in submerged mycelial culture of Ganoderma lucidum

Appl Biochem Biotechnol. 2006 Sep;134(3):249-62. doi: 10.1385/abab:134:3:249.


In submerged culture of Ganoderma lucidum, the pH optimum for cell growth has been shown to be lower than that for exopolysaccharides (EPS) formation. Therefore, in the present study, a two-stage pH-control strategy was employed to maximize the productions of mycelial biomass and EPS. When compared, a batch culture without pH control had a maximum concentration of EPS and endopolysaccharides, which was much lower than those with pH control. Maximum mycelial growth (12.5 g/L) and EPS production (4.7 g/L) were achieved by shifting the controlled pH from 3.0 to 6.0 after day 4. The contrast between the controlled-pH process and uncontrolled pH was marked. By using various two-stage culture processes, it was also observed that culture pH has a significant affect on the yield of product, mycelial morphology, chemical composition, and molecular weight of EPS. A detailed observation of mycelial morphology revealed that the productive morphological form for EPS production was a dispersed pellet (controlled pH shifting from 3.0 to 6.0) rather than a compact pellet with a dense core area (controlled pH 4.5) or a feather-like pellet (controlled pH shifting from 6.0 to 3.0). Three different polysaccharides were obtained from each pH conditions, and their molecular weights and chemical compositions were significantly different.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bioreactors / microbiology*
  • Cell Culture Techniques / methods*
  • Cell Proliferation
  • Culture Media / chemistry*
  • Culture Media / metabolism*
  • Hydrogen-Ion Concentration
  • Polysaccharides / metabolism*
  • Reishi / cytology
  • Reishi / physiology*


  • Culture Media
  • Polysaccharides