Mixed Fermentation Of Gluconacetobacter Xylinus And Monascus Spp

As Chinese traditional functional food, Monascus can be used not only as drugs but also as food addition. Nata-de-coco is a white bacterial cellulose which is produced by Gluconacetobacter xylinum through fermentation of coconut water, it is rich in diatery fiber and its nano-structure is unique. This paper attempts to co-culture Monascus and Gluconacetobacter xylinus in fermented coconut water medium to develop a new Functionality Monascus-nata Complex Stuff.This health food mass combined the unique flavor and color and functional characteristics of Monascus, nata de coco and coconut water, it would lay the theoretical foundation for a new healthy food. Specific work as follows:1. The effect of coconut water contents, sucrose and ammonium sulfate concentrations, cultivation modes on the growth of Gluconacetobacter xylinus Y15 was investigated. When 25%(V/V) coconut water,3g/L (NH4)2SO4 was added into the medium without sucrose, and G. xylinus Y15 was cultivated in shake flask culture at 130r/min for 24h, the cell number could reach as high as 4.9×108CFU/mL, while the cell number was only 4.9x 104CFU/mL when cultivated in static culture.2. Measured the growth patterns of G xylinus Y15 in NCW (Nature Coconut Water)、FCW(Fermentated Coconut Water)、HS(S. Hestrin and M. Schramm) medium. The results showed that under the agitated culture conditions, the lag phase of G. xylinus Y15 in FCW and NCW is 16h, which is 20h shorter than HS, and the exponential phase in FCW is 40h, it is longer than in NCW and HS, and the cell number in FCW is bigger than other two in the same culture time, So FCW is more suitable for G. xylinus Y15 growth.3. The growth and metabolism condition of M. ruber As 3.549、M. anka ACCC32339、M. anka ACCC30192、M. purpureus ACCC30141 were studied in coconut water medium.(1) The colony and mycelia morphology were observed separately by microscope, and found the mycelia of M. ruber As 3.549 grows faster and more branches. Some hyphae cross each other to form a web structure. However the mycelia of other 3 is less branches. A tentative inference on this result is that M. ruber As 3.549 may be more suitable to form a complex structure with the smooth bacterial cellulose silk.(2) Compared the pigment and monaklin K production of 4 monascus strains in PDB and FCW medium, and found that M. ruber As 3.549 is the weakest in the four. However, the difference betwween M. ruber As 3.549 and other three monascus strains is that, the pignent and monaklin K production of As 3.549 in FCW medium is slightly higher than in the PDB, it seems that coconut water medium is more suitable for As 3.549 to accumulate pignents and monaklin K.For the reasons above, choose the M. ruber As 3.549 to co-culture with G xylinus Y15 in depth.4. The antagonistic experiment of G. xylinus Y15 and 4 monascus strains showed that:there is a certain degree of interference between G. xylinus Y15 and monascus hyphae, but the antagonism is not very significant.5. The co-culture condition of G. xylinus Y15 and 4 monascus strains were researched.We found that inoculation time and ventilation are key factor for the co-culture.The final co-culture conditions were determined as follows:fermented coconut water medium 60ml per 100mL flask, after inoculate G. xylinus Y15 for 1.5d, inoculate M. ruber As 3.549, total inoculation 3%, inoculation proportion 1:1.cultured at 30℃,130 r/min for 7 d, Uniform particles, beautiful appearance of villous spherical product can be harvest. The spherical particle is researched under microscope and scanning electron microscope, and found that the villi of the product is monascus mycelium and internal for the mixture of bacterial cellulose and monascus mycelium. Under this culture condition, G. xylinus Y15 is successfully co-ordinated growth with monascus.6. Studied the influence of different cellulose producer on co-culture products. It was found that the products of cellulose producers is significantly different, and their co-culture complex is diversity and variations in size and color. Even the similar single pure culture product, their co-culture complex with the same As 3.549 is widely different. This may due to the variation of different metabolize way of different cellulose producer.7. Studied the impact of different monascus strains on co-culture complex. Found that it has a great impact on appearence(especially particle external villus),particle size, uniform degree,and pigments value. The pigment value after co-culture is dramatically higher than monoculture monascus.8. The internal structure of co-culture complex were researched, found that mycelia deep into the bacterial cellulose, and G. xylinus Y15 grown on the mycelia with cellulose produced which realized the good collaborative symbiosis. The product is both rich in bacterial cellulose and mycelia, and the cellulose is the mainly compound.