Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, College of Life Sciences, Nankai University, Tianjin, 300071, China.
Key Laboratory of Bioactive Materials for Ministry of Education, College of Life Sciences, Nankai University, Tianjin, 300071, China.
Microb Cell Fact. 2024 Aug 31;23(1):237. doi: 10.1186/s12934-024-02515-w.
Ectoine as an amino acid derivative is widely applied in many fields, such as the food industry, cosmetic manufacturing, biologics, and therapeutic agent. Large-scale production of ectoine is mainly restricted by the cost of fermentation substrates (e.g., carbon sources) and sterilization.
In this study, Halomonas cupida J9 was shown to be capable of synthesizing ectoine using xylose as the sole carbon source. A pathway was proposed in H. cupida J9 that synergistically utilizes both WBG xylose metabolism and EMP glucose metabolism for the synthesis of ectoine. Transcriptome analysis indicated that expression of ectoine biosynthesis module was enhanced under salt stress. Ectoine production by H. cupida J9 was enhanced by improving the expression of ectoine biosynthesis module, increasing the intracellular supply of the precursor oxaloacetate, and utilizing urea as the nitrogen source. The constructed J9U-P8EC achieved a record ectoine production of 4.12 g/L after 60 h of xylose fermentation. Finally, unsterile production of ectoine by J9U-P8EC from either a glucose-xylose mixture or corn straw hydrolysate was demonstrated, with an output of 8.55 g/L and 1.30 g/L of ectoine, respectively.
This study created a promising H. cupida J9-based cell factory for low-cost production of ectoine. Our results highlight the potential of J9U-P8EC to utilize lignocellulose-rich agriculture waste for open production of ectoine.
作为一种氨基酸衍生物，海藻糖广泛应用于食品工业、化妆品制造、生物制品和治疗剂等领域。海藻糖的大规模生产主要受到发酵基质（如碳源）和灭菌成本的限制。
本研究表明，盐单胞菌 J9 能够利用木糖作为唯一碳源合成海藻糖。在 H. cupida J9 中提出了一条协同利用 WBG 木糖代谢和 EMP 葡萄糖代谢合成海藻糖的途径。转录组分析表明，在盐胁迫下，海藻糖生物合成模块的表达增强。通过增强海藻糖生物合成模块的表达、增加前体草酰乙酸的细胞内供应以及利用尿素作为氮源，提高了 H. cupida J9 中海藻糖的产量。构建的 J9U-P8EC 在木糖发酵 60 小时后实现了 4.12 g/L 的海藻糖产量记录。最后，展示了 J9U-P8EC 未经灭菌从葡萄糖-木糖混合物或玉米秸秆水解物中生产海藻糖的能力，分别获得了 8.55 g/L 和 1.30 g/L 的海藻糖产量。
本研究构建了一种有前景的基于盐单胞菌 J9 的细胞工厂，用于低成本生产海藻糖。我们的结果强调了 J9U-P8EC 利用富含木质纤维素的农业废弃物进行开放生产海藻糖的潜力。
