Department of Biotechnology, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.
Department of Chemical Engineering for Energy Resources, East China University of Science and Technology, Shanghai, China.
Biotechnol Bioeng. 2022 Dec;119(12):3509-3525. doi: 10.1002/bit.28222. Epub 2022 Sep 19.
The halophilic bacterium Halomonas elongata DSM 2581 generally adapts well to high level of salinity by biosynthesizing ectoine, which functions as an important compatible solute protecting the cell against external salinity environment. Halophilic bacteria have specific metabolic activities under high-salt conditions and are gradually applied in various industries. The present study focuses on investigating the physiological and metabolic mechanism of H. elongata DSM 2581 driven by the external salinity environment. The physiological metabolic dynamics under salt stress were investigated to evaluate the effect of NaCl stress on the metabolism of H. elongata. The obtained results demonstrated that ectoine biosynthesis transited from a nongrowth-related process to a growth-related process when the NaCl concentration varied from 1% to 13% (w/v). The maximum biomass (X = 41.37 g/L), and highest ectoine production (P = 12.91 g/L) were achieved under 8% NaCl. Moreover, the maximum biomass (X ) and the maximum specific growth rates (μ ) showed a first rising and then declining trend with the increased NaCl stress. Furthermore, the transcriptome analysis of H. elongata under different NaCl concentrations demonstrated that both 8% and 13% NaCl conditions resulted in increased expressions of genes involved in the pentose phosphate pathway, Entner-Doudoroff pathway, flagellar assembly pathway, and ectoine metabolism, but negatively affected the tricarboxylic acid cycle and fatty acid metabolism. At last, the proposed possible adaptation mechanism under the optimum NaCl concentration in H. elongata was described.
嗜盐菌 Halomonas elongata DSM 2581 通常通过生物合成作为重要相容溶质的 e ct oine 来很好地适应高盐度，以保护细胞免受外部盐环境的影响。嗜盐菌在高盐条件下具有特定的代谢活性，并且正在逐渐应用于各个行业。本研究主要关注受外部盐环境驱动的 H. elongata DSM 2581 的生理和代谢机制。研究了盐胁迫下的生理代谢动态，以评估 NaCl 胁迫对 H. elongata 代谢的影响。结果表明，当 NaCl 浓度从 1%（w/v）变化到 13%（w/v）时，e ct oine 生物合成从非生长相关过程转变为生长相关过程。在 8%NaCl 下，获得了最大生物量（X = 41.37 g/L）和最高的 e ct oine 产量（P = 12.91 g/L）。此外，最大生物量（X ）和最大比生长速率（μ ）随 NaCl 胁迫的增加呈先上升后下降的趋势。此外，不同 NaCl 浓度下 H. elongata 的转录组分析表明，8%和 13%NaCl 条件均导致戊糖磷酸途径、Entner-Doudoroff 途径、鞭毛组装途径和 e ct oine 代谢相关基因的表达增加，但对三羧酸循环和脂肪酸代谢产生负面影响。最后，描述了 H. elongata 在最佳 NaCl 浓度下可能的适应机制。
