Studies On Pigments Production By Monascus With Purple Sweet Potato Starch Using Submerged Fermentation Technology

Purple sweet potato (Lopmoea batata L ) was taken as raw material for Monascus submerged fermentation cultivation. Effect of the starch from purple sweet potato on pigments production by Monascus was studied. The culture medium and cultivation conditions for Monascus producing red pigments were optimized with Response Surface Methodology, and the fermentation kinetics of Monascus submerged fermentation was also investigated. The main research context and findings were summarized as follows:The ability of pigments production by Monascus with purple sweet potato starch as carbon resource was investigated. The indices of the dry cell weight of Monascus mycelium and pigments content were assessed. The results showed that the dry cell weight and pigments yield by Monascus in the substrate contained purple sweet potato starch were 111.38 %and 82.77 %, respectively, compared with that in the substrate contained white sweet potato. Visible spectrum scan of Monascus pigments produced in the substrate contained purple sweet potato starch was carried out, two maximum absorptions at 410 nm and 506 nm respectively was observed. Furthermore, the components of Monascus pigments was analysed with HPLC, the results showed that the Monascus pigments might be primarily consisted of seven components.Taken purple sweet potato as carbon resource, Corn Slurry, Tryptone, Yeast Extract, L-Glutamate Natrium, (NH₄)₂SO₄ and NaNO₃ as nitrogen resource was added to the substrate respectively. The effect of these substances mentioned above on the ability of pigments production of Monascus was observed. The results indicated that Tryptone and L-Glutamate Natrium were the most suitable for pigments production by Monascus as nitrogen resources. Thereby, the effect of the contents of purple sweet potato starch, Tryptone and L-Glutamate Natrium on the ability of pigments production of Monascus was assessed with the second-order polynomial mathematic model, analysis of variance showed that this model used in the experiment was significant (P=0.0103), the determination R² was 0.947 . when the substrate contained 12.63 %purple sweet potato starch, 1.1 % tryptone, 0.35 % L-Glutamate Natrium, a maximum predicted value of 177.009 u·ml^-1 of Monascus pigments yield was obtained.The effects of submerged fermentation conditions on the pigments production by Monascus were studied with second-order polynomial mathematic model. Analysis of...