The Study On The Production Of Monascus Red/Orange/Yellow Pigments In Submerged Fermentation

Natural food colorant produced by Monascus fermentation is considered to be one of themost successful examples of the world’s natural colorant product by microbial fermentation.Nowadays, there are about12kinds of Monascus which can produce at less3sorts ofpigments, including red pigment, yellow pigment and orange pigment. In this study, we aim tolay a solid foundation for producing different color tune (red pigment/yellow pigment/orangepigment) by strains screening, mutation as well as the manners of Monascus pigmentsfermentation and the identification of Monascus pigments characteristics.In this study, we focus on the submerged fermentation technology of producing differentcolor tune of Monascus pigments. The main results are as follows:The conditions of preparing protoplasts of Monascus sp. H1102were studied, the fungusage was40h and the hydrolysis time was2.5h and the best regeneration medium was PDAwith0.6mol·L-1sucrose. The protoplasts were mutated by UV light, from which a higherpigment producing strain Monascus sp. H1102-5was obtained with the low citrininconcentration was only0.62mg·L-1. To improve the red pigment production. single-factor andorthogonal experiments were designed. The optimal fermentation medium were as follows:80g·L-1of maltose,135mL·L-1of soybean meal,3.5g·L-1of MgSO4and0.04g·L-1of ZnSO4,in which the concentration of Monascus red pigment was up to495U·mL-1, which had anincrease of112%.When8%of extractants was added, the biomass increased by38.41%compared to thecontrol, while yellow pigment and orange pigment were increased by15.85%and29.02%respectively. Addition of extractants can change the cell flocculation, and then form a largeamount of mycelia with high dispersion. Extractants has the ability of extracting yellow andorange fat-soluble pigments, thus the yellow and orange pigments were enriched in extractantphase. In addition, extractants provided the necessary fatty acids for pigment synthesis andcell growth.According to the fact that orange and yellow pigments could enriched in the extractantsand combined by the characteristics of Monascus pigments, a biphasic fermentation system ofproducing orange pigment and yellow pigment was established, in which inorganic nitrogenmedium was used. At the beginning of the fermentation, the biphasic fermentation system wasformed by adding20mL of extractants into the50mL fermentation medium. Thefermentation was carried out at32℃, the stirring rate was170r·min-1and the period was5d.The characteristics of10Monascus strains were investigated in the biphasic fermentationsystem. The strains only producing orange pigment or yellow pigment were screened in thissystem. The high-value yellow and orange pigment production strains were Monascus sp.961and Monascus sp. W1respectively, which produced up to200U·mL-1yellow pigment and436U·mL-1orange pigment respectively.The wavelength of maximum absorption and the Rfvalue were determined by fullwavelength scan and plate chromatography respectively. The wavelength of maximumabsorption and the value of Rfwere used for qualitative and quantitative analysis of yellow and orange pigments produced by the biphasic fermentation system. The results showed thatyellow and orange pigments produced by the biphasic fermentation system compliance withnatural yellow and orange pigments characteristics.