两阶段氮源补料策略促进微拟球藻EPA高效积累

为促进微拟球藻EPA高效积累,本研究探索了光照强度和氮源种类对微拟球藻生理生化及EPA相对含量的影响;根据光照和氮源实验结果设计两阶段氮源补料策略,并优化了氮源补料时间。结果表明:光强从1 000 lux增加至9 000 lux,微拟球藻比生长速率从0.25 d~(-1)增加至0.54 d-1,油脂含量从11.4%增加至20.2%,而EPA相对含量从25.5%降低至13.1%;培养10 d后乙酸铵组生物量和油脂含量最高,分别为0.41 g·L~(-1)和14.3%,硝酸钠组EPA相对含量最高,为27.1%;两阶段硝酸钠加乙酸铵培养模式,最佳乙酸铵补料时间为第11 d,培养20 d最终生物量及EPA相对含量分别为0.68 g·L~(-1)和24.3%。采用两阶段氮源补料策略能促进微拟球藻高效积累EPA。

Efficient accumulation of EPA from N.oculata by two stage feeding of nitrogen

To improve the relative EPA content of fatty acid products from N.oculata,the effects of light intensity and the types of nitrogen source on the growth,biochemical composition and the relative contents of EPA were studied.Based on the experimental results of light intensity and nitrogen,the two stages of nitrogen source feeding experiments were designed and the timing of nitrogen feeding was optimized.The results showed that the specific growth rate increased from 0.25 d-1 to 0.54 d-1,the oil content increased from 11.4％ to 20.2％ while the EPA content decreased from 25.5％ to 13.1％ when the light intensity increased from 1 000 lux to 9 000 lux;ammonium acetate was found to be the best for the growth and oil of N.oculata,and its biomass could reach 0.41 g · L-1 and oil content was 14.3％,the EPA content of the nitrate group was highest,which reached 27.1％;By optimizing the timing of feeding of ammonium acetate,the biomass and relative EPA content of N.oculata reached 0.68 g · L-1 and 24.3 ％ respectively,which were higher than those of the control group by 15.3％ and 7.5％,and the optimum feeding time of ammonium acetate was the llth day.