Research On Metabolic Regulation And Antioxidant Activity Of Lycopene By Neurospora Crassa

Lycopene is an acyclic carotene component by 11 conjugated double bonds of unsaturated hydrocarbons. It is an important terpenoid pigment of carotenoids and belongs to a precursor of β-carotene metabolism synthesis. Lycopene has unique long-chain structure which makes it have strong antioxidant capacity; It could be used to regulate tumor cell proliferation, prevent and inhibit the malignant tumor. The important value in food and medical fields, lycopene is known as the "plant gold", and our country has approved it as a food coloring and nutritional supplements.1. In order to study microbial fermentation production of lycopene by Neurospora crassa, through Box-Behnken design to optimize the fermentation conditions, by means of the grinding method combined ultrasonication to break cells and with ethyl acetate-acetone(2:1, V/V)mixed organic solvent to extract pigment, high performance liquid chromatography(HPLC) analysis was carried out on the product, the conditions of liquid phase is acetonitrile-dichloromethane(55:45, V/V)as mobile phase and detection at 472 nm to separate lycopene significantly. The optimal shake flask fermentation production process is: temperature 30℃, 6.5% inoculation quantity, 100 r/min oscillate and cultivate 110 h. It could obtain lycopene up to 10.10 mg/L finally.2. By means of analysising the microbial synthesis pathway of lycopene, the fermentation agent is added in the culture medium for metabolic regulation, determinate the lycopene contents of mycelia and ascospore respectively, the accumulation of lycopene could increase by adding a certain amount of metabolic regulation content during microbial metabolites synthesis. Experiments show that, ergosterol biosynthesis inhibitor fluconazole with the concentration of 2.0 mg/L was added to the medium at 40 h that making the optimal consequence in mycelia 57.31 μg per gram of dry cells, which was 81.3% higher than that of the control; The results suggested that the best time to add the inhibitor was at 48 h while the content could be achieved 168.75 μg per gram of dry ascospore, which was 58.82% higher than that of the control; While adding the nocotine with the concentration of 25 m L/L at 48 h could make the optimal consequence to 328.51 μg/g, 2.38 times of initial lycopene yield 137.86 μg/g.3. Research the cell disruption by means of grinding and ultrasonic crushing method, and by using organic solvent as extraction agent, design in different condition of extraction temperature, time, ratio of solvent through the orthogonal experiment design method to explore the extraction effect, determine the optimal requirement: grinding-ultrasonic to broken bacteria, organic solvent ethyl acetate-acetone(1:1, V/V) ratio of mixed as extraction agent, 65 ℃ under the condition of leaching time 2.5 h, lycopene extraction from Neurospora crassa fermentation product is the best extraction result.4. The effect on the capacity of lycopene in vitro antioxidant compared with VE and Vc. In the range of experimental concentration, the half clearance SC50 of lycopene extraction were 32.6, 110.05, 42.7 μg/ml on Lipid peroxidation、DPPH? radical and O2-? radical, respectively; While the half clearance SC50 of VE is 78.1、210 and 1500 μg/ml, respectively; The half clearance SC50 of Vc is 5100、80 and 119 μg/ml. The lycopene extraction has lower ?OH scavenging activities and reducing power than Vc and VE. In conclusion, lycopene extracttion fermented by Neurospora crassa has rather greater radical scavenging ability and a certain reducing power.