Research On Extraction, Purification,Characterization And Biological Activity Of Carotenoids In Deinococcus Radioyugnans

Deinococcus is a genus of bacteria that can adapt to extreme environment. This genus does not produce spores, not be motive. Most of the bacteria are red to orange-red pigmented. Temperature between30℃to37℃is available for such genus to be cultured. It has strong resistance to radiation and it can also endure high temperature, desiccation, low temperature, oxidizing agents and other extreme stresses. Unique tolerance mechanisms of this genus have not been fully understood. Our previous studies showed that the carotenoids in Deinococcus radiodurans (DR) are involved in the mechanism of bacterial to oxidative stress.Carotenoids usually refer to C40hydrocarbons and their oxidized derivatives commonly found in photosynthetic bacteria, algae, plants and some non-photosynthetic bacteria. About10%of the carotenoids are precursors of vitamin A. On the other hand, carotenoids also can scavenge free radicals, enhance immunity and prevent against cancer and tumors. Microbial fermentation synthesis has become a major means of the natural carotenoids production. DR, as a prokaryotic microorganism, possesses simple production process, short fermentation time, easy extraction and high carotenoid yield. All of these advantages provide a new strain resource for microbiological biosythesis of natural carotenoids and provide a experimental basis for carotenoids industrialized production from DR. Other strains in Deinococcus, such as Deinococcus radiopugnans (DRP), shows the same property of anti-radiation, antioxidation. The bacteria are red pigmented indicating they can produce carotenoids. Since little research on carotenoids in DRP has been carried out, we have extracted carotenoids from DRP and studied on the extraction, purification, characterization and biological activity.1. We extracted carotenoids from DRP and analysised its composition compared with DR by high performance liquid chromatography (HPLC) under several different conditions. We found that the major carotenoids in such two strains seemed similar while some components appeared different. We would focus on such different points. Comparison of carotenoids production from these two strains showed that under laboratory conditions carotenoids production in DRP was about four times to as that in DR, DRP provides a better resource for microbiological assay fermentantion and provide the basis for the promotion of the use of carotenoids as well. 2. We purified the carotenoids through silica gel column and thin layer chromatography. From such experiments we found the purification efficiency of the main product in DRP was up to4%, while it was up to25%in DR. Therefore, DRP carotenoids purification by silica gel column was relatively low and there’s need for other means to improve the efficiency of the purification of the DRP products.3. We also studied the antioxidant capacity of both crude and pure carotenoids in DRP and DR. The vitro and vivo activity assays had been carried out. The results show that DRP had effective scavenging activity of reactive oxygen radicals. We found that carotenoid antioxidant activity of two strains had some differences. Fenton method and chemiluminescence analysies showed that carotenoids of DRP have stronger hydroxyl radical and superoxide radical scavenging ability. The cellular level experiments showed that purified carotenoids from DRP had strong inhibition of cell damage caused by hydrogen peroxide. When its concentration reached2.5μg/ml, purified caroteniods from DRP had relatively stronger inhibition on induced cell damage.