Center for Systems Biology and Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, 101 Reykjavík, Iceland.
Biomedical Center and Department of Anatomy, Faulty of Medicine, University of Iceland, 101 Reykjavík, Iceland.
Mar Drugs. 2018 Aug 4;16(8):272. doi: 10.3390/md16080272.
Diatoms are a major group of unicellular algae that are rich in lipids and carotenoids. However, sustained research efforts are needed to improve the strain performance for high product yields towards commercialization. In this study, we generated a number of mutants of the model diatom , a cosmopolitan species that has also been found in Nordic region, using the chemical mutagens ethyl methanesulfonate (EMS) and -methyl-'-nitro--nitrosoguanidine (NTG). We found that both chlorophyll and neutral lipids had a significant correlation with carotenoid content and these correlations were better during exponential growth than in the stationary growth phase. Then, we studied common metabolic pathways and analyzed correlated enzymatic reactions between fucoxanthin synthesis and pigmentation or lipid metabolism through a genome-scale metabolic model. The integration of the computational results with liquid chromatography-mass spectrometry data revealed key compounds underlying the correlative metabolic pathways. Approximately 1000 strains were screened using fluorescence-based high-throughput method and five mutants selected had 33% or higher total carotenoids than the wild type, in which four strains remained stable in the long term and the top mutant exhibited an increase of 69.3% in fucoxanthin content compared to the wild type. The platform described in this study may be applied to the screening of other high performing diatom strains for industrial applications.
硅藻是一种富含脂类和类胡萝卜素的单细胞藻类，然而，需要持续的研究努力来提高菌株的性能，以实现高产品产量，从而实现商业化。在这项研究中，我们使用化学诱变剂乙基甲磺酸（EMS）和 N-甲基-N-硝基-N-亚硝基胍（NTG）对模式硅藻进行了大量突变体的生成，模式硅藻是一种世界性的物种，也在北欧地区被发现。我们发现叶绿素和中性脂质与类胡萝卜素含量有显著的相关性，这些相关性在指数生长期比在静止生长期更好。然后，我们通过基因组规模的代谢模型研究了常见的代谢途径，并分析了岩藻黄素合成与色素沉着或脂质代谢之间的相关酶反应。通过将计算结果与液相色谱-质谱数据相结合，揭示了相关代谢途径的关键化合物。我们使用基于荧光的高通量方法筛选了大约 1000 株菌株，并选择了 5 株突变株的总类胡萝卜素比野生型高出 33%，其中 4 株在长期内保持稳定，而最佳突变株的岩藻黄素含量比野生型增加了 69.3%。本研究中描述的平台可应用于筛选其他具有工业应用潜力的高性能硅藻菌株。
