Novak Katharina, Kutscha Regina, Pflügl Stefan
Research Area Biochemical Engineering, Environmental and Bioscience Engineering, Institute for Chemical, Technische Universität Wien, Gumpendorfer Straße 1a, 1060 Vienna, Austria.
Biotechnol Biofuels. 2020 Oct 22;13:177. doi: 10.1186/s13068-020-01816-7. eCollection 2020.
Acetate is an abundant carbon source and its use as an alternative feedstock has great potential for the production of fuel and platform chemicals. Acetoin and 2,3-butanediol represent two of these potential platform chemicals.
The aim of this study was to produce 2,3-butanediol and acetoin from acetate in W. The key strategies to achieve this goal were: strain engineering, in detail the deletion of mixed-acid fermentation pathways W Δ Δ Δ Δ 445_Ediss and the development of a new defined medium containing five amino acids and seven vitamins. Stepwise reduction of the media additives further revealed that diol production from acetate is mediated by the availability of aspartate. Other amino acids or TCA cycle intermediates did not enable growth on acetate. Cultivation under controlled conditions in batch and pulsed fed-batch experiments showed that aspartate was consumed before acetate, indicating that co-utilization is not a prerequisite for diol production. The addition of aspartate gave cultures a start-kick and was not required for feeding. Pulsed fed-batches resulted in the production of 1.43 g l from aspartate and acetate and 1.16 g l diols (2,3-butanediol and acetoin) from acetate alone. The yield reached 0.09 g diols per acetate, which accounts for 26% of the theoretical maximum.
This study for the first time showed acetoin and 2,3-butanediol production from acetate as well as the use of chemically defined medium for product formation from acetate in . Hereby, we provide a solid base for process intensification and the investigation of other potential products.
乙酸盐是一种丰富的碳源，将其用作替代原料在燃料和平台化学品生产方面具有巨大潜力。3-羟基丁酮和2,3-丁二醇是其中两种潜在的平台化学品。
本研究的目的是利用W菌从乙酸盐生产2,3-丁二醇和3-羟基丁酮。实现这一目标的关键策略包括：菌株工程改造，具体为删除混合酸发酵途径WΔΔΔΔ445_Ediss，以及开发一种含有五种氨基酸和七种维生素的新型限定培养基。逐步减少培养基添加剂进一步表明，乙酸盐生成二醇的过程由天冬氨酸的可用性介导。其他氨基酸或三羧酸循环中间体无法使菌株在乙酸盐上生长。在分批和脉冲补料分批实验的受控条件下培养表明，天冬氨酸在乙酸盐之前被消耗，这表明共利用不是二醇生产的先决条件。添加天冬氨酸能使培养物快速启动，且补料时不需要添加。脉冲补料分批培养从天冬氨酸和乙酸盐中生产出1.43 g/l，仅从乙酸盐中生产出1.16 g/l二醇（2,3-丁二醇和3-羟基丁酮）。产量达到每克乙酸盐0.09 g二醇，占理论最大值的26%。
本研究首次展示了从乙酸盐生产3-羟基丁酮和2,3-丁二醇，以及使用化学成分限定的培养基从乙酸盐中生成产物。据此，我们为工艺强化和其他潜在产物的研究提供了坚实基础。
