Xie Yaru, Chen Lei, Sun Tao, Zhang Yanan, Li Ting, Song Xinyu, Zhang Weiwen
Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, China.
Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China.
Adv Exp Med Biol. 2018;1080:27-53. doi: 10.1007/978-981-13-0854-3_2.
Cyanobacteria are autotrophic prokaryotes that can perform oxygenic photosynthesis. The conversion of light and carbon dioxide into green fuels and chemicals has drawn considerable interest, and several dozen products have been successfully synthesized in genetically engineered cyanobacteria. However, during cultivation, cyanobacterial cells are typically exposed to various stresses from the environment, such as acid, salt and metal stresses, as well as from the end products they synthesize, such as ethanol, butanol, and 3-hydroxypropionic acid (3-HP). These stresses hinder the accumulation of biomass and the production of chemicals or biofuels in cyanobacteria. Thus, improving the ability of cyanobacterial cells to resist stress can potentially enhance the robustness of the cyanobacterial chassis and the final yield of the target products. Toward this goal, research has been performed to explore the mechanisms by which cyanobacteria respond to various environmental perturbations and product toxicity. Among these mechanisms, transporters are membrane proteins involved in the transportation of ions, small molecules, or macromolecules across the membrane, and they have been reported to be involved in the response to common stresses in many organisms. Thus, engineering transporter-encoding genes may be a promising solution to increase the resistance of the cells against biotic and abiotic stresses. This chapter focuses on recent progress on the use of transporters related to stress responses in the model cyanobacterium Synechocystis sp. PCC 6803 and presents an updated review of their functions in stress regulation and their potential application in future chassis modifications.
蓝藻是能够进行产氧光合作用的自养原核生物。将光和二氧化碳转化为绿色燃料和化学品已引起了广泛关注，并且已经在基因工程蓝藻中成功合成了几十种产品。然而，在培养过程中，蓝藻细胞通常会受到来自环境的各种胁迫，如酸、盐和金属胁迫，以及它们合成的终产物的胁迫，如乙醇、丁醇和3-羟基丙酸（3-HP）。这些胁迫阻碍了蓝藻中生物量的积累以及化学品或生物燃料的生产。因此，提高蓝藻细胞抵抗胁迫的能力可能会增强蓝藻底盘的稳健性和目标产品的最终产量。为了实现这一目标，已经开展了研究以探索蓝藻对各种环境扰动和产品毒性的响应机制。在这些机制中，转运蛋白是参与离子、小分子或大分子跨膜运输的膜蛋白，据报道它们参与了许多生物体对常见胁迫的响应。因此，对编码转运蛋白的基因进行工程改造可能是提高细胞对生物和非生物胁迫抗性的一种有前景的解决方案。本章重点介绍了模式蓝藻集胞藻PCC 6803中与胁迫响应相关的转运蛋白的使用的最新进展，并对它们在胁迫调节中的功能及其在未来底盘改造中的潜在应用进行了更新综述。
