α-ketoglutarate (AKG) is a valuable dicarboxylic acid with multiple applications in the food, pharmaceutical, and chemical industries. Its chemical synthesis is associated with toxic by-products, low specificity, and high energy input. To create a more environmentally friendly and sustainable alternative, a microbial production process for AKG was developed. Four potential producer strains were generated by metabolic engineering of Corynebacteriumglutamicum and characterized on defined glucose/sucrose media as well as molasses, a side stream from sugar beet processing. While strain C.glutamicum PO6-iolT1Δgdh ΔgltB mscCG’ ΔodhA was not able to grow on defined media it outperformed all predecessor variants on molasses. Successful scale-up into a fed-batch bioreactor process with molasses yielded 96.2g AKG with a conversion yield of 0.64gg−1. Finally, downstream processing by liquid–liquid extraction with ethyl acetate enabled product purification with an extraction efficiency of 87 % and an AKG purity of > 93 %.

中文翻译：

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从糖蜜到含有工程谷氨酸棒状杆菌的纯化 α-酮戊二酸


α-酮戊二酸 （AKG） 是一种有价值的二羧酸，在食品、制药和化学工业中具有多种应用。其化学合成与有毒副产物、低特异性和高能量输入有关。为了创造更环保和可持续的替代方案，AKG 开发了一种微生物生产工艺。通过谷氨酸棒状杆菌的代谢工程产生四种潜在的生产菌株，并在确定的葡萄糖/蔗糖培养基以及糖蜜（甜菜加工的副流）上进行表征。虽然菌株 C.glutamicum PO6-iolT1Δgdh ΔgltB mscCG' ΔodhA 无法在确定的培养基上生长，但它在糖蜜上的表现优于所有前身变体。成功放大到含糖蜜的补料分批生物反应器工艺中，可产生 96.2g AKG，转化率为 0.64gg-1。最后，通过乙酸乙酯液-液萃取进行下游处理，实现了提取效率为 87 % 的产品纯化，AKG 纯度为 > 93 %。