Laboratory of Algal, Systems, and Synthetic Biology, Division of Science and Math, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, UAE.
Center for Genomics and Systems Biology, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, UAE.
Sci Adv. 2017 Sep 1;3(9):e1603096. doi: 10.1126/sciadv.1603096. eCollection 2017 Sep.
Diatoms, considered as one of the most diverse and largest groups of algae, can provide the means to reach a sustainable production of petrochemical substitutes and bioactive compounds. However, a prerequisite to achieving this goal is to increase the solar-to-biomass conversion efficiency of photosynthesis, which generally remains less than 5% for most photosynthetic organisms. We have developed and implemented a rapid and effective approach, herein referred to as intracellular spectral recompositioning (ISR) of light, which, through absorption of excess blue light and its intracellular emission in the green spectral band, can improve light utilization. We demonstrate that ISR can be used chemogenically, by using lipophilic fluorophores, or biogenically, through the expression of an enhanced green fluorescent protein (eGFP) in the model diatom . Engineered cells expressing eGFP achieved 28% higher efficiency in photosynthesis than the parental strain, along with an increased effective quantum yield and reduced nonphotochemical quenching (NPQ) induction levels under high-light conditions. Further, pond simulator experiments demonstrated that eGFP transformants could outperform their wild-type parental strain by 50% in biomass production rate under simulated outdoor sunlight conditions. Transcriptome analysis identified up-regulation of major photosynthesis genes in the engineered strain in comparison with the wild type, along with down-regulation of NPQ genes involved in light stress response. Our findings provide a proof of concept for a strategy of developing more efficient photosynthetic cell factories to produce algae-based biofuels and bioactive products.
硅藻被认为是最多样化和最大的藻类群体之一，它为可持续生产石油化工替代品和生物活性化合物提供了途径。然而，实现这一目标的前提是提高光合作用的太阳能到生物质转换效率，而对于大多数光合生物来说，这一效率通常仍低于 5%。我们已经开发并实施了一种快速有效的方法，即细胞内光谱重组（ISR），通过吸收过量的蓝光并在绿光光谱带内进行细胞内发射，可以提高光的利用效率。我们证明，ISR 可以通过使用亲脂性荧光染料进行化学合成，也可以通过在模式硅藻中表达增强型绿色荧光蛋白（eGFP）进行生物合成。表达 eGFP 的工程细胞在光合作用中的效率比亲本菌株提高了 28%，同时在高光条件下有效量子产率提高，非光化学猝灭（NPQ）诱导水平降低。此外，池塘模拟器实验表明，在模拟户外阳光条件下，eGFP 转化体的生物量生产速率比野生型亲本菌株高出 50%。与野生型相比，工程菌株中的主要光合作用基因上调，而与光胁迫反应相关的 NPQ 基因下调。我们的研究结果为开发更高效的光合作用细胞工厂以生产基于藻类的生物燃料和生物活性产品提供了一个概念验证。
