Effects of cyclic AMP on development and secondary metabolites of Monascus ruber M-7

Aim: To study effects of cyclic adenosine monophosphate (cAMP) on development and secondary metabolites of Monascus ruber M‐7. Methods and Results: Plate culture, liquid‐state fermentation (LSF) and solid‐state fermentation (SSF) were used to evaluate effects of cAMP on colonial growth, spore formation and polyketide production of Strain M‐7. The results revealed that the variation trends of colonial sizes, numbers of sexual spores and red pigment contents of M‐7 were in a dose‐dependent manner. And generally they increased and decreased with cAMP concentrations in the ranges of low cAMP concentrations and high cAMP concentrations, respectively. But the variation trends of numbers of asexual spores and citrinin production in both LSF and SSF were opposite to those of colonial sizes, sexual sporulation and red pigment. Conclusions: The regulation of cAMP on development and secondary metabolites in Strain M‐7 was in a dose‐dependent pattern. And red pigment might convert to citrinin under changing cAMP concentrations. Significance and Impact of the Study: The effects of cAMP on Strain M‐7 in SSF give a new clue to enhance beneficial polyketides and reduce citrinin produced by M. ruber.