Klebsiella oxytoca is widely used for the biological production of 2,3-butanediol (2,3-BDO), a promising platform chemical with a broad range of applications. Here, to improve cell growth and production of 2,3-BDO under high concentration of xylose (100 g/L), we engineered K. oxytoca using an adaptive laboratory evolution and a biosensor-derived high throughput screening strategy. First, we developed a XylR-dependent xylose biosensor for the detection of intracellular xylose, and K. oxytoca containing the xylose biosensor was used for adaptive laboratory evolution in 100 g/L xylose. Cells were isolated by FACS screening, and the isolated strain (KO8S16) showed much improved cell growth with high xylose consumption rate (1.35 g/L/h) and 2,3-BDO productivity (0.53 g/L/h) compared with the wild-type strain. Through whole genome resequencing, it was revealed that a mutation in OmpR (a response regulator of osmotic stress) allowed to withstand high concentrations of xylose. Finally, fed-batch cultivation was performed by feeding high concentration of xylose, and K. oxytoca successfully produced 2,3-BDO at a concentration as high as 57.5 g/L by consuming 238.13 g/L xylose in 47 h.

中文翻译：

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高浓度木糖生产 2,3-丁二醇的催产克雷伯菌工程

Klebsiella oxytoca广泛用于生物生产 2,3-丁二醇 (2,3-BDO)，这是一种具有广泛应用前景的平台化学品。在这里，为了在高浓度木糖 (100 g/L) 下改善细胞生长和 2,3-BDO 的产生，我们使用适应性实验室进化和生物传感器衍生的高通量筛选策略设计了催产芽孢杆菌。首先，我们开发了一种 XylR 依赖性木糖生物传感器，用于检测细胞内木糖和催产克雷伯菌含有木糖生物传感器的木糖被用于在 100 g/L 木糖中进行适应性实验室进化。通过 FACS 筛选分离细胞，与分离菌株 (KO8S16) 相比，分离菌株 (KO8S16) 表现出明显改善的细胞生长、高木糖消耗率 (1.35 g/L/h) 和 2,3-BDO 生产率 (0.53 g/L/h)。野生型菌株。通过全基因组重测序，发现 OmpR（渗透压力的反应调节剂）中的突变允许耐受高浓度的木糖。最后，通过添加高浓度木糖进行补料分批培养，催产克雷伯菌通过在 47 小时内消耗 238.13 g/L 木糖，成功生产了浓度高达 57.5 g/L 的 2,3-BDO。