Production of red pigment by submerged culture of Paecilomyces sinclairii

Aims: From a survey of submerged culture of edible mushrooms, a high pigment‐producing fungus Paecilomyces sinclairii was selected and its optimal culture conditions investigated. Methods and Results: The optimal culture conditions for pigment production were as follows: inoculum age, 3 d; temperature, 25 °C; initial pH, 6·0; carbon source, 1·5% (w/v) soluble starch; nitrogen source, 1·5% (w/v) meat peptone. Although addition of 10 mmol l−1 CaCl2 to the culture medium slightly increased pigment production, most of the bio‐elements examined had no notable or detrimental effect on pigment production. Conclusions: Under the optimal conditions obtained in the flask culture tested, a ninefold increase in pigment production (4·4 g l−1) was achieved using a 5‐l batch fermenter. Paecilomyces sinclairii secreted water‐soluble red pigment into the culture medium. The pigment colour was strongly dependent on the pH of the solution: red at pH 3–4, violet at pH 5–9 and pink at pH 10–12. Significance and Impact of the Study: The high concentration of pigment (4·4 g l−1) produced by P. sinclairii demonstrates the possibility of commercial production of pigment by this strain, considering its relatively high production yield and light stability.