Xi Yimei, Xue Song, Cao Xupeng, Chi Zhanyou, Wang Jinghan
Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
School of Bioengineering, Dalian University of Technology, Dalian, 116024, China.
Bioresour Bioprocess. 2021 Oct 21;8(1):104. doi: 10.1186/s40643-021-00457-4.
Accumulation of β-carotene in Dunaliella salina is highly dependent on light exposure intensity and duration, but quantitative analysis on photon numbers received per cell for triggering β-carotene accumulation is not available so far. In this study, experiment results showed that significant β-carotene accumulation occurred after at least 8 h illumination at 400 µmol photons·m·s. To quantify the average number of photons received per cell, correlations of light attenuation with light path, biomass concentration, and β-carotene content were, respectively, established using both Lambert-Beer and Cornet models, and the latter provided better simulation. Using Cornet model, average number of photons received per cell (APRPC) was calculated and proposed as a parameter for β-carotene accumulation, and constant APRPC was maintained by adjusting average irradiance based on cell concentration and carotenoids content changes during the whole induction period. It was found that once APRPC reached 0.7 µmol photons cell, β-carotene accumulation was triggered, and it was saturated at 9.9 µmol photons cell. This study showed that APRPC can be used as an important parameter to precisely simulate and control β-carotene production by D. salina.
盐生杜氏藻中β-胡萝卜素的积累高度依赖于光照强度和持续时间，但目前尚无关于触发β-胡萝卜素积累时每个细胞接收光子数的定量分析。在本研究中，实验结果表明，在400 μmol光子·m⁻²·s⁻¹的光照下至少照射8小时后，β-胡萝卜素出现显著积累。为了量化每个细胞接收的平均光子数，分别使用朗伯-比尔模型和科内特模型建立了光衰减与光程、生物量浓度和β-胡萝卜素含量的相关性，后者提供了更好的模拟效果。使用科内特模型计算了每个细胞接收的平均光子数（APRPC），并将其作为β-胡萝卜素积累的一个参数，在整个诱导期内根据细胞浓度和类胡萝卜素含量的变化调整平均辐照度，以维持APRPC恒定。研究发现，一旦APRPC达到0.7 μmol光子/细胞，就会触发β-胡萝卜素积累，在9.9 μmol光子/细胞时达到饱和。本研究表明，APRPC可作为精确模拟和控制盐生杜氏藻β-胡萝卜素产量的一个重要参数。
