Ethanol-tolerant Arthrobacter simplex is desirable since ethanol facilitates hydrophobic substrates dissolution on an industrial scale. Herein, alterations in compatible solutes were investigated under ethanol stress. The results showed that the amount of trehalose and glycerol increased while that of glutamate and proline decreased. The trehalose protectant role was verified and its concentration was positively related to the degree of cell tolerance. otsA, otsB and treS, three trehalose biosynthesis genes in A. simplex, also enhanced Escherichia coli stress tolerance, but the increased tolerance was dependent on the type and level of the stress. A. simplex strains accumulating trehalose showed a higher productivity in systems containing more ethanol and substrate because of better viability. The underlying mechanisms of trehalose were involved in better cell integrity, higher membrane stability, stronger reactive oxygen species scavenging capacity and higher energy level. Therefore, trehalose was a general protectant and the upregulation of its biosynthesis by genetic modification enhanced cell stress tolerance, consequently promoted productivity.

中文翻译：

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在暴露于乙醇期间，单纯节杆菌中的溶质适应性变化以及海藻糖对抗逆性和生物转化性能的影响。

由于乙醇在工业规模上促进疏水性底物的溶解，因此需要乙醇耐受的单纯节杆菌。在此，研究了乙醇胁迫下相容性溶质的变化。结果表明，海藻糖和甘油的量增加，而谷氨酸和脯氨酸的量减少。证实了海藻糖保护剂的作用，其浓度与细胞耐受程度呈正相关。单纯曲霉中的三个海藻糖生物合成基因otsA，otsB和treS也增强了大肠杆菌的压力耐受性，但增加的耐受性取决于压力的类型和水平。积聚海藻糖的单纯曲霉菌株在含有更多乙醇和底物的系统中显示出更高的生产率，因为其具有更好的生存能力。海藻糖的潜在机制涉及更好的细胞完整性，更高的膜稳定性，更强的活性氧清除能力和更高的能级。因此，海藻糖是一种一般的保护剂，通过基因修饰上调其生物合成可增强细胞的抗逆性，从而提高生产力。