Boto Santiago T, Gerges Kareem, Bardl Bettina, Rosenbaum Miriam A
Bio Pilot Plant Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute Jena Germany.
Faculty of Biological Sciences Friedrich Schiller University Jena Germany.
Eng Life Sci. 2025 Jan 23;25(1):e202400076. doi: 10.1002/elsc.202400076. eCollection 2025 Jan.
Sustainable chemical production from C gaseous substrates, such as syngas or CO/H, can be achieved through gas fermentation. In gas fermentation, acetogenic bacteria are able to utilize oxidized inorganic carbon sources as the sole carbon source and electron acceptor, while reduced inorganic species are used as the electron donor. , a model acetogen, is only capable of reducing CO to acetate and ethanol, with H as electron donor. In order to expand the product profile of this bacterium, five alcohol acetyltransferases (AATs) from yeast were heterologously expressed in to evaluate its potential to produce ethyl acetate. When growing on CO and H, up to 7.38 ± 0.43 mg/L of ethyl acetate were produced. Using fructose as the main carbon and energy source, up to 23.15 ± 1.28 mg/L of ethyl acetate were produced. Ethanol and fumarate supplementation were able to boost ethyl acetate titers (up to 37.51 ± 9.44 mg/L). Hence, ethyl acetate production was enabled in at low titers, which could be explained by the high energetic cost of operation of AATs, and their shown promiscuity. However, we also show that this opens the door to more complex esterification reactions of higher added value biomolecules.
通过气体发酵可以实现从气态碳底物（如合成气或CO/H₂）进行可持续的化学品生产。在气体发酵中，产乙酸细菌能够利用氧化态无机碳源作为唯一碳源和电子受体，而还原态无机物质用作电子供体。例如，模式产乙酸菌只能以H₂作为电子供体将CO还原为乙酸和乙醇。为了扩展这种细菌的产物谱，来自酵母的五种醇乙酰基转移酶（AATs）在该菌中进行了异源表达，以评估其生产乙酸乙酯的潜力。当以CO和H₂为底物生长时，乙酸乙酯的产量高达7.38±0.43mg/L。以果糖作为主要碳源和能源时，乙酸乙酯产量高达23.15±1.28mg/L。添加乙醇和富马酸盐能够提高乙酸乙酯的滴度（高达37.51±9.44mg/L）。因此，该菌能够以低滴度生产乙酸乙酯，这可以通过AATs运行的高能量成本及其表现出的混杂性来解释。然而，我们也表明，这为更高附加值生物分子的更复杂酯化反应打开了大门。
