Study On Monascus Anka Solid-stste Fermentation

The use of monascus pigment as food additive has a long history. In the admixture of monascus pigments, yellow pigments are the best fresh pigments, which were only prepared in a very small scale in laboratory, and have not been expanded and applied adequately. Because of its particular and striking color, it is one of monascus pigments which are worth to exploit, and its production will have a good prospect. Therefore, the systemic studying about the development of this monascus yellow pigments and how to increase the yield of the yellow pigments have a great significance both of theoretic and praxis.To enhance the value of yellow pigments, this paper deal with MYM2(Monascus anka mutant 2) as original stain, and used solid-state fermentation in stain mutation and in the culture condition optimization. It explored a simple, high-productive and high-quality route to product the yellow pigments in solid-state fermentation and provided some useful theoretical and experimental basis for the solid-state fermentation production of yellow pigments.First, I mutated the stain. I used a complex way included UV, DES, LiCl and NGT to get a monascus mutant named MYM21(Monascus anka mutant 21) which is suitable of solid-state fermentation. It has a good capability in yellow pigment production. The value can reach 2500U/g, 3.57 times before the mutation, which was about 700U/g. It has a stable genetic. The value of yellow pigment did not decrease after passing 6 times.In order to optimize the solid-state fermentation conditions for yellow pigment production by Monascus anka mutant 21. A four-factor and three-level orthogonal test was conducted on the basis of single factor experiments. The optimal process condictions proved as follows: the mixture of rice and corn with the proportion of 2:1 as the best substrate, the moisture content as 45%, the inoculums as 1.8mL, the humidity as 80%, culture temperature as 31℃, mid-term replenishment as 15% and culture time as 12d. The monascus yellow pigment value has enhanced 2.66 times after the optimization, from 2500U/g to 6656.34 U/g. The color tone is 0.90.The stability of yellow pigments was detected. The heat-stability is quite well. It can last a long time at 80℃, and has a 80% residual rate after water bath 6h at 100℃. The yellow pigments have a weak light-stability. The yellow pigment has a 68.90% residual rate, and the red pigment has a 75.02% residual rate after 24h with the irradiation of nature light. The UV has a great damage at the pigments. After the 120 mins UV irradiation, the yellow pigment has a 44.56% residual rate, and the red pigment has a 50.13% residual rate. The reducing of the pigments is very strong and is very sensitive with the oxidant. They will decomposition sharply when the H2O2 concentration is 14g/L. The yellow pigment has a 20.67 residual rate, and the red pigment has a 32.54% residual rate.