Yang Bo, Liu Jin, Ma Xiaonian, Guo Bingbing, Liu Bin, Wu Tao, Jiang Yue, Chen Feng
Institute for Food and Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China.
BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China.
Biotechnol Biofuels. 2017 Oct 5;10:229. doi: 10.1186/s13068-017-0916-8. eCollection 2017.
Photosynthetic microalgae are emerging as potential biomass feedstock for sustainable production of biofuels and value-added bioproducts. CO biomitigation through these organisms is considered as an eco-friendly and promising alternative to the existing carbon sequestration methods. Nonetheless, the inherent relatively low photosynthetic capacity of microalgae has hampered the practical use of this strategy for CO biomitigation applications.
Here, we demonstrate the feasibility of improving photosynthetic capacity by the genetic manipulation of the Calvin cycle in the typical green microalga . Firstly, we fused a plastid transit peptide to upstream of the enhanced green fluorescent protein (EGFP) and confirmed its expression in the chloroplast of . Then we introduced the cyanobacterial fructose 1,6-bisphosphate aldolase, guided by the plastid transit peptide, into chloroplast, leading to enhanced photosynthetic capacity (~ 1.2-fold) and cell growth. Molecular and physiochemical analyses suggested a possible role for aldolase overexpression in promoting the regeneration of ribulose 1,5-bisphosphate in the Calvin cycle and energy transfer in photosystems.
Our work represents a proof-of-concept effort to enhance photosynthetic capacity by the engineering of the Calvin cycle in green microalgae. Our work also provides insights into targeted genetic engineering toward algal trait improvement for CO biomitigation uses.
光合微藻正成为可持续生产生物燃料和增值生物产品的潜在生物质原料。通过这些生物体进行二氧化碳减排被认为是一种比现有碳封存方法更环保且有前景的替代方案。然而，微藻固有的相对较低的光合能力阻碍了该策略在二氧化碳减排应用中的实际应用。
在此，我们证明了通过对典型绿藻卡尔文循环进行基因操作来提高光合能力的可行性。首先，我们将质体转运肽融合到增强型绿色荧光蛋白（EGFP）的上游，并证实其在叶绿体中的表达。然后，我们在质体转运肽的引导下，将蓝藻果糖1,6-二磷酸醛缩酶导入叶绿体，导致光合能力增强（约1.2倍）和细胞生长。分子和理化分析表明醛缩酶过表达在促进卡尔文循环中核酮糖1,5-二磷酸再生和光系统中能量转移方面可能发挥作用。
我们的工作代表了通过对绿藻卡尔文循环进行工程改造来提高光合能力的概念验证。我们的工作还为针对藻类性状改良以用于二氧化碳减排的靶向基因工程提供了见解。
