Abstract:

The addition of plant growth regulators is a currently promising strategy to promote DHA accumulation in Schizochytrium sp. and increase its yield. The addition of a single plant growth regulator has been reported to promote the accumulation of DHA in Schizochytrium sp., but the synergistic promotion of DHA accumulation in Schizochytrium sp. by the addition of two plant growth regulators at the same time has rarely been reported. In this study, two plant growth regulators, diethyl aminoethyl hexanoate (DA-6) and 2,4-dichlorophenoxyacetic acid (2,4-D) were used to synergistically induce the accumulation of DHA in Schizochytrium sp., increasing the content and yield of DHA. The synergistic concentration of DA-6 and 2,4-D was optimized using DHA as an indicator. The results showed that when 0.05mg/L DA-6 combinating with 0.5mg/L 2,4-D was used, the biomass and oil contents did not significantly increase, compared to supplemented DA-6 group and control group without plant growth regulator. But the DHA content and yield increased significantly and reached the highest values, which were 58.32% and 5.17g/L, respectively. Compared to supplemented DA-6 group, DHA content and yield increased by 0.17 times and 0.23 times, respectively; compared to control group without plant growth regulator, DHA content and yield increased by 0.48 times and 0.48 times, respectively. The results of this work indicated that synthetic plant growth regulators with appropriate concentration could synergically induce DHA accumulation in Schizochytrium sp. to increase DHA production, which provided a new idea and strategy for large-scale industrial production of DHA.

Key words: diethyl aminoethyl hexanoate, 2,4-dichlorophenoxyacetic acid, Schizochytrium sp., plant growth regulator, docosahexaenoic acid

摘要：

目前添加植物生长调节剂是一种促进裂殖壶菌中二十二碳六烯酸（DHA）积累以及提高其产量很有潜力的策略。添加单一植物生长调节剂促进裂殖壶菌DHA积累已有报道，但同时添加两种植物生长调节剂协同促进裂殖壶菌中DHA积累鲜见报道。本工作采用合成植物生长调节剂胺鲜酯（DA-6）和2,4-二氯苯氧乙酸（2,4-D）协同诱导裂殖壶菌积累DHA，提高DHA含量和产量，以DHA为指标优化了DA-6和2,4-D的最佳协同浓度。结果表明：0.05mg/L DA-6和0.5mg/L 2,4-D协同处理裂殖壶菌，裂殖壶菌生物量和油脂含量没显著增加，但DHA含量和产量显著增加，分别达到58.32%和5.17g/L，相比于单独添加DA-6分别增加17%和23%，相比于未添加植物生长调节剂的空白对照组分别增加了48%和48%。本研究表明适宜浓度的合成植物生长调节剂可协同诱导裂殖壶菌中DHA的积累，提高DHA产量，为大规模工业化生产DHA提供新的思路和策略。

关键词: 胺鲜酯, 2,4-二氯苯氧乙酸, 裂殖壶菌, 植物生长调节剂, 二十二碳六烯酸