Abstract:

The development of highly efficient CO₂ utilization technologies can alleviate the urgent pressure on the environment and energy, playing a vital role in achieving the goal of “carbon peak and neutrality”. Microalgae are an important group of photoautotrophic microorganisms, providing the main source of primary productivity in the biosphere, and also serving as important model organisms for photosynthesis research. In recent years, microalgae have also been considered as promising chassis for photosynthetic biosynthesis, directly converting solar energy and carbon dioxide into various bio-based products. This technological route is called photosynthetic biomanufacturing, which possesses the advantages of simultaneous carbon fixation and clean production. This review focuses on the perspectives of development models and application scenarios, and suggests trends related to the further development of photosynthetic biomanufacturing. Regarding the efforts to harness and utilize photosynthetic carbon flow in microalgae cells, we summarized and compared three widely adopted strategies, including novel species screening, environmental perturbations, and genetic engineering. The research progress, significant breakthrough, and representative application demonstration of development models were systematically summarized. In the future, the combination of promising chassis cells with desired industrial properties, systematic metabolic engineering to remodel the native metabolism, and specific environmental treatments to maximize synthesis capacities could be expected to generate next-generation advanced microalgae cell factories. The optimized microalgae cell factories with desired photosynthesis and biosynthesis properties could be expected to play important roles in the areas of biomedical therapy, biophotovoltaics, and bioastronautics through interdisciplinary technology cooperation and integrations. Microalgal synthetic biology is also expect to focus on solving emerging problems rising from new application scenarios and larger application scales, including the development and optimization of the synthetic biology toolboxes, engineering chassis cells toward more efficient photosynthesis, the development of anti-biocontamination and biosafety strategies for large-scale cultivation. Taken together, this review provides useful and updated information to facilitate the development of photosynthetic biosynthesis route with carbon fixation and clean production, providing certain feasible solutions for the "carbon peak and neutrality".

Key words: microalgae, photosynthetic biomanufacturing, cell factory, synthetic biology, development mode

摘要：

发展CO₂的高效资源化利用技术可同时缓解迫切的环境和能源压力，是实现“双碳”目标的重要途径。微藻是重要的光合固碳微生物，是生物圈初级生产力的主要来源，也是研究光合作用的重要模式体系。近年来，微藻又被视为极具潜力的新型微生物光合平台，具有将太阳能和CO₂直接转化为各种生物基产品的潜力，该生产模式被称为光驱固碳合成技术，可以同时起到固碳减排和绿色合成的效果，是有望助力“双碳”战略目标实现的新型生物制造技术路线。微藻光驱固碳合成技术本质上是通过微藻光合代谢网络重塑实现CO₂的资源化利用，对该方面本文系统总结了“拆盲盒”“挤海绵”“动刀子”3种基本开发模式的研究进展、重要突破和代表性应用示范。而微藻光合代谢网络的深度重塑，又有效扩展了基于微藻光驱固碳合成过程的技术应用场景，在这一方面，本文着重总结微藻生物技术与生物医学、生物光伏、生物航天技术等新型应用场景和技术领域的交叉融合。最后，还针对微藻光驱固碳合成技术在应用中面临的挑战，提出应该重点从合成生物学工具箱开发、高效光合平台开发、规模化培养防污染和防逃逸策略开发等几个环节进行攻关，以加强微藻光驱固碳合成过程的可控制性和可应用性。

关键词: 微藻, 光驱固碳, 细胞工厂, 合成生物学, 开发模式