Studies On Fermentation Optimization And Pigments’ Qualities Of Prodigiosins Production Serratia Marcescens

Natural pigments from microorganism not only be used as coloring agent, but also be researched on their physiological activities. Therefore, they are considered to be functional pigments. Prodigiosins is a kind of nature red pigments, which is a secondary metabolite produced by microbes. With the continuous research, many physiological activities of prodigiosins were discovered, such as anti-bacteria, anti-diahhrea, antimycotic and antiprotozoals. And people have focused on the immunodepression and apoptosis of carcinoma cells of prodigiosins.In this study, strains produced pigments were screened from the natural environment. The strain Sm-128with prodigiosins produced was identified as Serratia marcescens. Prodigiosin production was enhanced through the optimizations of medium components and the culture conditions. Efficiency of prodigiosins extraction was improved by optimizations of extraction conditions. The structural analysis was carried out after purification of prodigiosins.(1)16strains produced pigments were isolated from different natural conditions. A prodigiosins production strain named Sm-128was identified as Serratia marcescens by traditional and molecular ways. The16SrDNA sequence of Sm-128was registered in GenBank (Accession number:HQ834310). And it was preservation in Chinese typical microorganism training center (CCTCC NO:M2010347).(2) To improve the production of prodigiosins, the medium components and the culture conditions were optimized. After signal factor assay, glyceol, peptone and initial pH was chosen to study by response surface method. Regression equation was established to calculate the optimal fermentation conditions (glycerin0.93%, peptonel.4%, initial pH8.8). After optimization, the prodigiosins yield was13times as much as base medium.(3) To maximize the intracellular prodigiosins, the extraction efficiency was compared in different crushing methods. Under the shaking flask condition,the biomass was not high enough to be worked in high-speed homogenizer, the prodigiosins extraction was proceed in trituration and60%ethanol in pH2. While higher biomass obtained in jar fermentation, ferment broth was extracted by ethyl acetate after high-speed homogenizer treatment.(4) As a natural pigment, the study on property of prodigiosins was obvious important. The assays about metal ions indicated that Fe, Zn, Na, K improved the pigment yield, while Cu, Ca reduced it. Prodigiosins has an excellent thermostabilization, but was sensitive to sunlight and ultraviolet light and high concentrations of reducing agent.(5) Prodigiosins produced by Sm-128was eventually divided into three components through thin layer chromatography (TLC) and column chromatography (LTC). The component b1was confirmed to be prodigiosins by UV and H-NMR. The molecular structure component b2which contained benzene ring structure has not been determined.