Chiang Mai Journal of Science

 This work characterized the fermentation and Monascus pigments production of Monascus anka mutant in a 5L bioreactor under the different ammonium salt conditions: ammonium chloride, ammonium sulfate or ammonium nitrate. All the experimental results obtained in this work suggest that not the pH environment established by ammonium salts but ammonium salts itself played a critical role on the production of Monascus pigments and the growth of Monascus anka mutant. ammonium ion could inhibits the activity of some key enzyme for Monascus pigments synthesis and the inhibition effect on some key enzyme for Monascus red pigments synthesis is stronger than on some key enzyme for Monascus yellow pigments synthesis. Key enzyme for inhibited Monascus pigments production would be researched clearly by experiments in our future researching.