碳氮源和盐度对异养黄丝藻脂肪酸产量的影响

Effects of Carbon and Nitrogen Sources and Salinity on Fatty Acid Production of Tribonema sp.

[目的]以分离获得的一株黄丝藻ENN172(Tribonemasp.)为材料,优化异养培养工艺,提高脂肪酸产量。[方法]研究黄丝藻ENN172在1g/L初始接种浓度黑暗培养时,不同葡萄糖浓度、不同氮源NaNO3、酵母提取物、蛋白胨、尿素以及NaCl浓度对细胞生物量和脂肪酸含量的影响。[结果]葡萄糖20g/L时生物量最高但脂肪酸含量最低,随浓度增加,生长速率下降,脂肪酸含量增加,综合比较,30g/L时脂肪酸产量最高。蛋白胨1g/L培养10d时,生物量达到对照组的2.3倍,脂肪酸产量是对照的2.1倍。添加2g/L酵母提取物培养10d时,生物量达到对照的1.7倍,脂肪酸产量是对照组的1.6倍。蛋白胨和酵母提取物对ENN172生物量及脂肪酸产量均有促进作用,添加硝酸钠和尿素对脂肪酸产量无显著促进。NaCl10g/L时在第6天脂肪酸含量达到最大27.03%(与初始相比提高3.4倍),添加NaCl可促进脂肪酸积累但不利于生物量增加。[结论]通过优化脂肪酸生产条件,葡萄糖30g/L为低氮条件最佳诱导浓度,蛋白胨和酵母提取物可以作为脂肪酸生产优选氮源,在诱导期添加NaCl利于提高脂肪酸含量。综上结果,黄丝藻作为新型能源微藻具有一定异养生产脂肪酸的能力,深入优化培养条件仍有上升空间,有望成为微藻产业化养殖的潜力藻株。

[Objective] A strain of Tribonema sp. was used as a material to optimize the heterotrophic culture process and increase the yield of fatty acids.[Method] The effect of the concentration of glucose, different nitrogen sources including sodium nitrate, yeast extract, peptone, urea and sodium chloride on coded as ENN172 in this research was examined. The initial culture concentration was kept at1 g/L for all experiments.[Result]The highest biomass production and the lowest fatty acid content was obtained with the glucose concentration at20 g/L. The biomass production decreased and fatty acid content increased with the increasing of glucose concentration, with the fatty acid content reaching the highest at 30 g/L of glucose.The addition of1 g/L peptone and2 g/L yeast extract increased the biomass significantly, with the biomass reaching2.3 and1.7 times, respectively, compared to that of the control in10 days. However, there was no effect identified by introducing sodium nitrate and urea to the culture.The lipid content peaked at27.03%(3.4 times)of the dried biomass in 6 days with sodium chloride concentration at10g/L while the biomass production was suppressed as expected.[Conclusion] Overall, the optimized condition for lipid production is by keeping glucose at 30 g/L and nitrogen at a very low condition (1.5 g/L of NaNO 3). In addition, peptone and yeast extract can be used as a nitrogen source, and sodium chloride was an effective way to generate high lipid concentration biomass when needed. In conclusion, this particular Tribonema strain is capable of producing lipid with heterotrophic culture, which has the potential to be used as a commercial strain.