Optimization Of Culture Condition By Monascus 3.782 And Marine Bacteria 00856 For Bioactive Product

Microbial secondary metabolites from microbial organisms have a wealth of structural and functional diversity, so it is of significance to conduct the study about secondary metabolites. This thesis focuses on the research of the optimal conditions to produce the secondary metabolites from Monascus strains and marine bacteria and their product.Monascus is well known for its largely monascus pigments,the industrial and medical value and so on from the metabolites are much important. Initial water content of solid-state media was firstly optimized to improve the monascus pigment porduction in Monascus anka As 3.782 strain. The result indicated that the optimum water ratio was 30% approximately. Further orthogonal experiment design showed that the optimum liquid media with the components of 9% rice powder, 3% NaNO3, 0.3% KH2PO4, 0.1% MgSO4 and 0.5% soybean powder at pH 4.0 will produce high level of monascus pigment color value, which could reach 77.3 U/mL. The good mutated strain was screened at the distanece of 20 cm ultraviolet(UV)light irradiation in 3 min duration. The results indicated that the production of monascus pigment in solid-state fermentation could reach 1156.667 U/mL, with over three times of the pigment produciton of original strain. In the liquid fermentation, color value in the mutated strains increased two times of their parent strain pigment production.Marine bacteria are capable of producing a lot of unique bioactive substances, which have bright prospect in research and development. At the same time, a marine gorgonian-symbiotic bacterium (SCSIO No. 00856) was taxonomically identified by morphological analysis and 16S rDNA gene sequencing, and the bioactive metabolites production was further studied. This strain was classified as Bacillus sp., and its bioactive metabolites could inhibit the growth of Saccharomyces cerevisias and Staphylococcus aureus when cultured in the selected cultivation medium (pH 7.0) at 28℃. The growth curve of this strain and the fermentation time for antibacterial metabolites was also investigated. With the filter paper diffusion method and orthogonal experiment, the culture medium was optimized for producing the highest bioactive metabolites. Taking Saccharomyces cerevisias as indicator bacteria, the optimum medium was: sea salt 26.25 g/L, glucose 12 g/L, yeast extract 3 g/L, monopotassium phosphate 3 g/L, malt extract 5 g/L, and the best fermentation time was 6 days.