Studies On The High Yield EPA Of The Mutant Strain Of The Mortierella Alpine

Eicosapentaenoic acid(EPA),which belongs to the Omega-3 polyunsaturated fatty acids,and has important effects on human nutrition,development and health,it is the body’s own synthesis but indispensable and important nutrients.EPA is currently mainly from fish oil,but due to various factors of the environment,the source of EPA is very limited,making the use of microbial fermentation production of EPA research become a hot topic.This study I preserved mutant strain Mortierella alpina 200012201-12-2-2(hereinafter referred 12-2-2)as the starting fungi,firstly I conducted a study of its variable temperature that induced the yield of EPA and then optimized its best medium components and conditions of EPA ’s production.Finally I explored its feeding mode.The results are as follows:Firstly,to research the effects of temperature on the mutant strain Mortierella alpina 12-2-2 growth,metabolism,oil accumulation and EPA,ARA synthesis.Based on this,I selected the mode induced by the temperature variation effect on culturing mutant strain Mortierella alpina 12-2-2 to produce EPA,and designed four different variable temperature regulation strategies,and ultimately determined the best way of temperature changing: the Mortierella alpina is cultured 2d at 28 ℃,then cultured 3d when the temperature dropped to 20 ℃ and finally dropped the temperature to 12 ℃.Mortierella alpina oil production could reach 8.62 g / L,EPA yield up 158.39 mg / L,the highest content of EPA is incubated under conditions 2.68 times,at the same time,used this temperature variation mode,we can make ARA production reached 2.67 g / L.Secondly,through single factor experiment to find out the best carbon source,nitrogen source and other nutrients of EPA,and then through the Plackett-Burman experiment to find out the significant factors affecting the yield of EPA,and finally through the Plackett-Burman experiment to found out the optimum culture base composition: glucose dosage 89.64 g/L,yeast extract 12.71 g/L,precursor 2.01% and other ingredients.Under these conditions,the yield of EPA is 200.82 mg/L,which is improved by 27.09% than before optimizationThirdly,the single factor experiment was designed to optimize the influencing factors of EPA production,and the response surface optimization was carried out on the three factors,the results showed that the optimal culture conditions were as follows: inoculation amount 11%,initial pH6.5,culture time 12 d,EPA maximum yield was 255.9 mg/L,and the yield of EPA(202.142)increased by 26.59% than that before optimization.Fourthly,to discuss the disposable feeding process and residual glucose feedback feeding process mutant strain Mortierella alpina 12-2-2,the results showed: the best time of the disposable feeding process to feed glucose supplement was at 3d,the optimum concentration of sugar was 40 g/L;in the meantime,the best time of residual glucose feedback feeding process to feed glucose supplement was at 2d and 4d,the supplement concentration was 20 g/L.Compared with the no feeding process,the biomass of disposable feeding process and residual glucose feedback feeding process increased slightly,EPA,oil production increased significantly,increased by 10.57% and 35.08%.However,compared with disposable feeding process,the fermentation period shorte one day.