Optimization And Application Of Fermentation Technology For Producing Lycopene By Blakeslea Trispora

In recent years,with the continuous exploration of the physiological functions of lycopene,its application scope has been expanding and the market demand has been increasing.Chemical synthesis of lycopene is cheap,but there are potential safety hazards.The cost of extracting lycopene from plants is very high,so it is difficult to increase the yield greatly.Microbial fermentation has become a research and development hotspot because of its advantages of high safety,short production cycle and no seasonal restriction.In this study,the cyclase blockers for lycopene production by Blakeslea trispora were screened,and the fermentation conditions of lycopene were optimized,which laid a foundation for further study on the stability of lycopene in beverages.The main research results are as follows:1.To study the effects of 4 lycopene cyclase blockers,2-amino-6-methylpyridine,2,6-dimethylpyridine,2-methylimidazole,2-isopropyl imidazole,on the yield of lycopene.By comparing the effects of four blocking agents on the yield of lycopene,it was found that2-amino-6-methylpyridine as blocking agent had the highest yield.The single factor and orthogonal optimization experiments were carried out on the amount,time and fermentation time of 2-amino-6-methylpyridine best conditions were as follows: the amount of 2-amino-6-methylpyridine was 0.4 g/L,the time of addition was 42 h,the fermentation time was 144 h,and the optimized biomass was 38.85 g/L,lycopene content was 12.83 mg/g,lycopene yield was 498.59 mg/L,and lycopene purity was 90.11%.2.The effects of fermentation medium and fermentation conditions on lycopene production were studied.Through single factor experiment and response surface methodology,the composition of culture medium and fermentation conditions were optimized.It was found that there was a significant interaction between inoculation amount and liquid loading.Inoculation amount had the most significant effect on lycopene yield,followed by liquid loading,while inoculation rate was not significant.The optimum technological conditions were as follows: corn flour 20 g/L,soybean flour 25 g/L,potassium dihydrogen phosphate 0.6 g/L,magnesium sulfate 0.9 g/L,corn oil 12 g/L,initial p H of fermentation broth 6.5,inoculation amount 4.31%,liquid volume 40.36 m L/250 m L,inoculation ratio of positive and negative bacteria 1: 14.84.Here,from the fermentation kinetics curve of Blakeslea trispora,it can be seen that the strain is in the stage of rapid growth within 0 ? 2 days;The yield of lycopene increases rapidly within 2-6 days.After 6days,biomass and lycopene production decreased.3.The stability of lycopene to light was studied.The results showed that lycopene in fruit juice drinks and carbonated drinks faded rapidly within 18 days after being stored in outdoor natural light,and the fading rate was related to pigment concentration.Lycopene quickly fades in fruit juice drinks after being placed under indoor light for 18 days,while the preservation rate in carbonated drinks exceeds 64%.After 18 days of indoor storage away from light,the preservation rate of lycopene in carbonated drinks and fruit juice drinks was over 97% and 60% respectively.Studies on the thermal stability of lycopene showed that the lycopene was not lost after being stored for 6 h at 5-25 ?,and the preservation rate of lycopene and pigment reached over 82% and 56% after being stored for 6 h at 45-65?.The results showed that lycopene had higher thermal stability.