Wang Bo, Babele Piyoosh K, Crockett Miles N, Abraham Joshua P, Weidenbach Sara, Pfleger Brian F, Young Jamey D
Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235, USA; Department of Bioproducts and Biosystems Engineering, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St. Paul, MN, 55108, USA; Biotechnology Institute, University of Minnesota, St. Paul, MN, 55108, USA.
Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
Metab Eng. 2025 Nov;92:136-147. doi: 10.1016/j.ymben.2025.07.015. Epub 2025 Aug 5.
Cyanobacteria are capable of fixing CO using sunlight as the sole energy source and are promising microbial platforms for sustainable bioproduction of fuels, commodity chemicals, food and pharmaceuticals. L-lysine is an essential amino acid to humans and animals and is a precursor to synthesis of building blocks for nylon and polyesters. Its industrial production is currently solely based upon fermenting sugars by heterotrophic microorganisms such as Corynebacterium and Escherichia coli. Engineering cyanobacteria to effectively redirect photosynthetically fixed carbon towards lysine biosynthesis would provide a carbon-negative route of lysine production. In this study, to address the bottlenecks of lysine biosynthesis in the cyanobacterium Synechococcus sp. PCC 7002 (also called Picosynechococcus sp. PCC 7002), we combined targeted metabolomics and synthetic biology approaches to progressively identify and mitigate the major rate-limiting steps, ultimately increasing lysine productivity by about 77 % compared to the parental strain. The best engineered lysine-producing Synechococcus strain was able to produce up to 2.92 mM lysine within 5 days, with flux partitioning towards lysine peaking at 23 % of total fixed carbon under phototrophic conditions. The strategies demonstrated in this study can be used to guide rational metabolic engineering to identify and overcome pathway bottlenecks that limit flux to other renewable bioproducts in cyanobacteria.
蓝藻能够利用阳光作为唯一能源固定二氧化碳，是可持续生物生产燃料、商品化学品、食品和药品的有前景的微生物平台。L-赖氨酸是人和动物必需的氨基酸，是合成尼龙和聚酯构建单元的前体。其工业生产目前完全基于利用诸如棒状杆菌和大肠杆菌等异养微生物发酵糖类。对蓝藻进行工程改造，使其有效地将光合固定碳重新导向赖氨酸生物合成，将提供一条碳负性的赖氨酸生产途径。在本研究中，为了解决蓝藻聚球藻属PCC 7002（也称为微小聚球藻属PCC 7002）中赖氨酸生物合成的瓶颈问题，我们结合了靶向代谢组学和合成生物学方法，逐步识别并缓解主要的限速步骤，最终与亲本菌株相比，赖氨酸生产力提高了约77%。最佳的工程化产赖氨酸聚球藻菌株能够在5天内产生高达2.92 mM的赖氨酸，在光合条件下，流向赖氨酸的通量分配在总固定碳的23%时达到峰值。本研究中展示的策略可用于指导合理的代谢工程，以识别和克服限制蓝藻中其他可再生生物产品通量的途径瓶颈。
