多次补氮和增强蓝光促进三角褐指藻积累岩藻黄素

Promoting fucoxanthin accumulation in Phaeodactylum tricornutum by multiple nitrogen supplementation and blue light enhancement

摘要:

本研究旨在优化多次补氮和增强蓝光模式，以促进光发酵三角褐指藻(Phaeodactylum tricornutum)积累岩藻黄素。结果表明，在摇瓶中将含有胰蛋白胨和尿素的混合氮源(1:1，N mol/N mol；总氮浓度为0.02 mol/L)分6次加入培养系统是最佳的多次补氮模式；在5 L发酵罐中实施两阶段调光模式培养，在第二阶段增强蓝光(R:G:B=67.1:16.7:16.3)后，细胞密度、生物量生产率以及岩藻黄素的含量、产量和生产率分别达到1.12×10⁸ cells/mL、330 mg/(d·L)、19.62 mg/g、69.71 mg/L和6.97 mg/(d·L)。与红蓝光(R:G:B=70.9:18.3:10.9)下分6次补氮的一阶段培养相比，岩藻黄素含量显著提高了7.68% (P<0.05)，但生产率无显著差异(P>0.05)；与红蓝光(R:G:B=70.9:18.3:10.9)下一次性加入氮源的一阶段培养相比，岩藻黄素含量和生产率显著提高了45.98%和48.30% (P<0.05)。因此，本研究开发的多次补氮和增强蓝光的两阶段培养模式，有效促进了岩藻黄素积累、提高了氮源利用效率，为三角褐指藻光发酵生产岩藻黄素提供了新技术支撑。

Abstract:

The aim of this study was to promote fucoxanthin accumulation in Phaeodactylum tricornutum by photo-fermentation through optimizing the mode of multiple nitrogen supplementation and blue light enhancement. The results showed that the mixed nitrogen source (tryptone:urea=1:1, N mol/N mol; total nitrogen concentration at 0.02 mol/L) added to the culture system by six times was the best mode in shake flasks. Two-phase culture with light adjustment was then carried out in 5 L photo-fermenter with an enhanced blue light (R:G:B=67.1:16.7:16.3) in the second phase, leading to improved cell density (1.12×10⁸ cells/mL), biomass productivity (330 mg/(d·L)), fucoxanthin content (19.62 mg/g), titer (69.71 mg/L) and productivity (6.97 mg/(d·L)). Compared with one-phase culture under red/blue (R:G:B=70.9:18.3:10.9) light and six-times nitrogen supplementation, the fucoxanthin content was significantly increased by 7.68% (P<0.05) but the productivity did not change significantly (P>0.05). Compared with one-phase culture under red/blue (R:G:B=70.9:18.3:10.9) light and one-time nitrogen supplementation, the content and productivity of fucoxanthin were significantly increased by 45.98% and 48.30% (P<0.05), respectively. This study developed a two-phase culture mode with multiple nitrogen supplementation and blue light enhancement, which effectively promoted the accumulation of fucoxanthin and improved the efficiency of nitrogen source utilization, thus providing a new approach for fucoxanthin accumulation in P. tricornutum by photo-fermentation.