营养强化混养条件下提高色绿藻生物量和虾青素产量

Increasing Yields of Biomass and Astaxanthin by Chromochloris zofingiensis under Nutrient-enhanced Mixotrophic Conditions

摘要:

本研究在混养条件下，系统地比较了葡萄糖浓度、氮源种类以及不同碳氮比对色绿藻生物量和虾青素产率的作用规律。目的是在短时间内达到最高生物量同时获得较高含量的虾青素，为建立色绿藻高密度快速扩种和诱导积累虾青素应用技术提供科学依据。研究结果表明：在混养条件下，当葡萄糖浓度一定时，硝酸钠是细胞生长所需的最优氮源，6 d可达到最高生物量浓度9.23 g/L，平均比生长速率为0.24/d，虾青素产量为12.38 mg/L，虾青素占总类胡萝卜素的比例高达46.94%。至于不同碳氮比、葡萄糖浓度对色绿藻生物量和虾青素生产的影响，当葡萄糖浓度为30 g/L、C/N比为34为细胞生长的最优条件，生物量浓度最高为11.28 g/L，平均比生长速率高达0.32/d；虾青素含量显著优于其他组（p < 0.05），虾青素的产量为21.77 mg/L，虾青素占总类胡萝卜素的比例进一步提高到52.71%。本研究结果对于色绿藻高密度快速生长并积累大量虾青素的放大技术开发具有重要的指导意义。

Abstract:

This study systematically compared the effects of different glucose concentrations, nitrogen sources, and C/N ratios on the biomass and astaxanthin accumulation in Chromochloris zofingiensis under mixotrophic conditions. The aims were to obtain the highest biomass along with a relatively high content of astaxanthin in a short period of time, and provide a scientific basis for high-density seed-train expansion of Chromochloris zofingiensis and astaxanthin induction applied technologies. The results revealed that under mixotrophic conditions with a constant glucose concentration, NaNO3 was the most favorable nitrogen source for C. zofingiensis cell growth. The highest biomass concentration of 9.23 g/L was achieved on the sixth day of cultivation, with the average growth rate as 0.24/d, corresponding astaxanthin yield as 12.38 mg/L, and astaxanthin accounting for about 46.94% of total carotenoids in algal cells. As for the effects of different glucose concentrations and C/N ratios on cell growth and astaxanthin accumulation of C. zofingiensis, glucose concentration at 30 g/L and C/N ratio at 34 were found to be the optimal conditions for cell growth, resulting in the highest biomass of 11.28 g/L and average growth rate as 0.32/d, with significantly higher astaxanthin yield (21.77 mg/L, p < 0.05) and percentage of astaxanthin in total carotenoids (increased to 52.71%). The results obtained in this study will provide the guidance for rapid seed culture expansion and large-scale astaxanthin production by Chromochloris zofingiensis.