EFFECT OF NUTRITION OF MONASCUS SP ON FORMATION OF RED PIGMENTS

A higher producer of ascospores and pigments, Monascus strain TTWMB 6042, was used to study regulation of pigment production by nutrients. An initial medium containing 4% glucose, 0.3% NH4NO3 (75 mM nitrogen) and inorganic salts was used. We found that the formation of red pigments in this strain, measured by optical density at 500 nm (OD500) was strongly stimulated by monosodium glutamate (MSG) as the sole nitrogen source. The choice of carbon source and an initial pH of pH 5.5 were also important. High concentrations of phosphate and MgSO4 were inhibitory to pigment production. A new chemically defined medium was devised containing 5% maltose, 75 mM MSG, phosphate and MgSO4 at lower concentrations plus other mineral salts, which yielded a tenfold increase in OD500 and a reversal of the pigment location from predominantly cell-bound, including both intracellular and surface-bound pigments, to mainly extracellular.