Effect Of Oxygen-vectors And Surfactants On Rhodotorula Fermentations And Study On Intracellular Antioxidant Effects Of Lycopene

Lycopene as a biosynthetic intermediate for many carotenoids such as β- carotene, astaxanthin has the strongest antioxidant effect because of its 11 conjugated double bonds and two non-conjugated double bonds of unsaturated hydrocarbons, which is widely used for pigmentation of animal tissues and products, as well as for coloration of foods, drugs, and cosmetics due to its high nutritional and strong pigmenting value. Lycopene was also indicated for prevention of certain types of cancer, heart attack, and age-related macular degeneration.The analysis method of lycopene produced by mated Rhodotorula glutins strain 2.27 was obtained from the laboratory preserved fermentation using HPLC was founded. The conditions of HPLC were as follows. The chromatographic column was Agilent HCC18 column(5μm, 250 mm × 4.6 mm); the eluent were 42% acetonitrile、42% methanol and16% dichloromethane; the flow rate was1.5 m L / min; the detection wavelength was 472 nm; the injection volume was 10μL; the column temperature was 28-30℃.Addition of oxygen- vectors(n- hexane, n-dodecane, hexadecane) to fermentation medium was recognized as a method of enhancing oxygen transfer and promoting lycopene yield by Rhodotorula fermentation. n-dodecane as an oxygen-vector is the best in three kinds of liquid alkane. Experimental results show that, the biomass of Rhodotorula attained 16.49 g/L and the yield of lycopene biosynthetic reached 42.32 mg/L by Adding 4% n-dodecane in the 0h, which was 26.2% and 50.17% higher than the control group respectively.Addition of of non- ionic surfactants(Tween-80, Tween-20 and Triton X-100) to fermentation medium was recognized as to reduce surface tension, improve cell membrane permeability and promoting lycopene yield by Rhodotorula fermentation. Triton X-100 severely inhibited the growth of Rhodotorula.Orthogonal experimental method for joint regulation of surfactant and oxygen carriers were showed, the yield of lycopene reached 66.96 mg / L when addition of 6% n-dodecane, 1% n-hexadecane, 1.5% Tween 20, which was increased 166% than the control group respectively.Lycopene efficiently attenuated AAPH- induced oxidative stress in erythrocytes, inhibited the formation of MDA, and regulated intracellular antioxidant enzyme(GPx, SOD, and CAT)activities and Lycopene effectively attenuated AAPH- induced oxidative stress in erythrocytes and plasma, especially decreased copper- induced diene accumulation and protected plasma from oxidative damage.