Effects of divalent metal cations on lovastatin biosynthesis from Aspergillus terreus in chemically defined medium

摘要

Effects of six divalent metal cations: Fepo, Capo, Znpo, Mgpo, Cupoand Mnpo on fungal cell growth and lovastatin biosynthesis were investigated by submerged cultivation of Aspergillus terreus in a modified chemically defined medium. The influences of different initial concentrations of the above six metal cations were also examined at 1, 2, and 5 mM, respectively. Cupo apparently inhibited the cell growth, but had no influence on biosynthesis of lovastatin. All of Fepo, Capo, Znpo, Mgpo and Mnpo promoted the cell growth and lovastatin biosynthesis in different extents. The highest biomass of 13.8 pl 0.5 g lp# and specific lovastatin titres of 49.2 pl 1.4 mg gDCWp# were obtained at the level of 2 and 5 mM in the presence of Znpo, respectively. The values were improved double and 14.4-fold. Excess Znpo inhibited the cell growth, but enhanced lovastatin biosynthesis with an increment of 17.6 mg lp# per mM. The interactions of all metal cations slightly inhibited the lovastatin production comparing with the existence of Znpo, Fepo and Mgpo solely, yet remarkably improved the cell growth. These results suggest that the divalent metal ions Znpo or Fepo influence the production by regulating the action of key enzymes such as LovD or LovF in lovastatin biosynthesis.