SusChEM: Biological Auto-Enhancement of CO2 Absorption for Improved Cyanobacterial Growth and Biofuel Production

光养微生物利用阳光制造化学物质作为营养，它们有潜力成为“微生物化学工厂”，直接从大气中的二氧化碳中制造可持续燃料和化学物质，利用阳光和水作为能源。这种方法的一个技术挑战是含有微生物的水溶液对二氧化碳的吸收能力差。在其他转换二氧化碳的工业过程中，使用烷醇胺溶剂，如单乙醇胺（MEA），可用于提高CO2在水中的溶解度，从而提高其从气流中吸收的速度和效率。该项目旨在设计一种蓝藻生物模型，通过光合作用直接产生MEA。在产生的MEA存在的情况下，二氧化碳吸收到生物体培养基中的速度和效率将显著提高，因此，细胞生长和生物燃料生产的速度也将提高。此外，研究、教育和推广的多方面方法也将包括在内。该项目将作为几个高中和本科生研究项目的基础，包括富尔顿本科生研究计划（FURI）、生命科学本科生研究学院（SOLUR）和科学与工程经验（SCENE）项目，以招募女性和代表性不足的少数民族学生。将设计一种新的代谢途径，使聚囊藻sp. PCC 6803的内源性前体能够合成MEA。这将通过解除对天然前体生物合成途径的调节，然后引入和优化异源途径步骤的表达来实现。在水培养液中，CO2将与产生的MEA发生反应，然后通过一系列后续反应，最终生成碳酸氢盐。碳酸氢盐的细胞同化将促进产生的MEA的进一步再生，从而使其再次与额外的CO2分子反应。为了促进多边环境环境的生物再生，该项目将包括加强碳酸氢盐吸收的战略。最后，增强的CO2吸收将支持微生物更高的生长速率，增加的生长将支持更高的MEA生产速率，更高的MEA可用性将支持进一步改善的CO2吸收，最终产生自催化效应。这些策略将在野生型聚囊菌和先前设计的月桂酸生产菌株中进行研究，从而探索MEA生物合成对这种重要脂肪酸生物燃料前体生产的影响。

Phototrophic microorganisms, which use sunlight to make chemicals for their nutrition, possess potential as "microbial chemical factories" to make sustainable fuels and chemicals directly from atmospheric CO2, using sunlight and water for energy. One technical challenge to this approach is poor CO2 absorption into the aqueous solution containing the microbes. In other industrial processes that convert CO2, use of alkanolamine solvents such as monoethanolamine (MEA), can be used to enhance aqueous CO2 solubility and, in turn, the rate and efficiency of its absorption from gas streams. This project seeks to engineer a model cyanobacterium organism to produce MEA directly via photosynthesis. In the presence of produced MEA, the rate and efficiency of CO2 absorption into the organism's culture medium will be significantly enhanced and, as a result, so too will be rates of cell growth and biofuel production. In addition, a multi-faceted approach to research, education, and outreach will also be included. This project will serve as the basis for several high school and undergraduate student research projects involving the Fulton Undergraduate Research Initiative (FURI), School of Life Sciences Undergraduate Research (SOLUR), and the SCience and ENgineering Experience (SCENE) programs to recruit women and under-represented minority students. A novel metabolic pathway will be engineered to enable MEA biosynthesis from endogenous precursors in Synechocystis sp. PCC 6803. This will be achieved by deregulating a native precursor biosynthesis pathway, followed by the introduction and optimized expression of the heterologous pathway steps. Within the aqueous culture, CO2 will react with produced MEA and then, through a series of subsequent reactions, will ultimately be rendered as bicarbonate. Cellular assimilation of bicarbonate will promote further regeneration of produced MEA, thereby returning it to react again with additional CO2 molecules. To facilitate the biological regeneration of MEA, the project will include strategies to enhance bicarbonate uptake. In the end, enhanced CO2 absorption will support higher growth rates of the microbes, increased growth will support higher rates of MEA production, greater MEA availability will support further improved CO2 absorption, ultimately resulting in an auto-catalytic effect. These strategies will be investigated in both wild-type Synechocystis as well as a previously-engineered laurate-producing strain, thereby allowing the effects of MEA biosynthesis on the production of this important fatty acid biofuel precursor to be explored.