State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, Hubei, People's Republic of China.
Bioprocessing Technology Institute (BTI), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
Appl Environ Microbiol. 2023 Feb 28;89(2):e0156822. doi: 10.1128/aem.01568-22. Epub 2023 Feb 8.
The compound 2-phenylethanol (2-PE) is a bulk flavor and fragrance with a rose-like aroma that can be produced by microbial cell factories, but its cellular toxicity inhibits cellular growth and limits strain performance. Specifically, the microbe Bacillus licheniformis has shown a strong tolerance to 2-PE. Understanding these tolerance mechanisms is crucial for achieving the hyperproduction of 2-PE. In this report, the mechanisms of B. licheniformis DW2 resistance to 2-PE were studied by multi-omics technology coupled with physiological and molecular biological approaches. 2-PE induced reactive oxygen species formation and affected nucleic acid, ribosome, and cell wall synthesis. To manage 2-PE stress, the antioxidant and global stress response systems were activated; the repair system of proteins and homeostasis of the ion and osmotic were initiated. Furthermore, the tricarboxylic acid cycle and NADPH synthesis pathways were upregulated; correspondingly, scanning electron microscopy revealed that cell morphology was changed. These results provide deeper insights into the adaptive mechanisms of B. licheniformis to 2-PE and highlight the potential targets for genetic manipulation to enhance 2-PE resistance. The ability to tolerate organic solvents is essential for bacteria producing these chemicals with high titer, yield, and productivity. As exemplified by 2-PE, bioproduction of 2-PE represents a promising alternative to chemical synthesis and plant extraction approaches, but its toxicity hinders successful large-scale microbial production. Here, a multi-omics approach is employed to systematically study the mechanisms of B. licheniformis DW2 resistance to 2-PE. As a 2-PE-tolerant strain, B. licheniformis displays multifactorial mechanisms of 2-PE tolerance, including activating global stress response and repair systems, increasing NADPH supply, changing cell morphology and membrane composition, and remodeling metabolic pathways. The current work yields novel insights into the mechanisms of B. licheniformis resistance to 2-PE. This knowledge can also be used as a clue for improving bacterial performances to achieve industrial-scale production of 2-PE and potentially applied to the production of other relevant organic solvents, such as tyrosol and hydroxytyrosol.
化合物 2-苯乙醇（2-PE）是一种具有玫瑰香气的大宗风味和香料，可通过微生物细胞工厂生产，但它的细胞毒性会抑制细胞生长并限制菌株性能。具体来说，地衣芽孢杆菌对 2-PE 表现出很强的耐受性。了解这些耐受机制对于实现 2-PE 的超生产至关重要。在本报告中，通过多组学技术结合生理和分子生物学方法研究了地衣芽孢杆菌 DW2 对 2-PE 的抗性机制。2-PE 诱导活性氧的形成，并影响核酸、核糖体和细胞壁的合成。为了应对 2-PE 应激，激活了抗氧化和全局应激反应系统；启动了蛋白质修复系统和离子及渗透压的内稳态。此外，上调了三羧酸循环和 NADPH 合成途径；相应地，扫描电子显微镜显示细胞形态发生了变化。这些结果深入了解了地衣芽孢杆菌对 2-PE 的适应机制，并突出了遗传操作的潜在目标，以增强 2-PE 抗性。能够耐受有机溶剂对于高浓度、高产量和高生产效率生产这些化学品的细菌至关重要。以 2-PE 为例，2-PE 的生物生产代表了一种有前途的替代化学合成和植物提取方法的选择，但它的毒性阻碍了成功的大规模微生物生产。在这里，采用多组学方法系统研究了地衣芽孢杆菌 DW2 对 2-PE 的抗性机制。作为一种 2-PE 耐受菌株，地衣芽孢杆菌显示出多种 2-PE 耐受机制，包括激活全局应激反应和修复系统、增加 NADPH 供应、改变细胞形态和膜组成以及重塑代谢途径。本研究为地衣芽孢杆菌抵抗 2-PE 的机制提供了新的见解。这些知识也可以作为提高细菌性能以实现 2-PE 工业规模生产的线索，并可能应用于生产其他相关有机溶剂，如酪醇和羟基酪醇。
