Salt stress improves thermotolerance and high-temperature bioethanol production of multi-stress-tolerant Pichia kudriavzevii by stimulating intracellular metabolism and inhibiting oxidative damage.
Salt stress improves thermotolerance and high-temperature bioethanol production of multi-stress-tolerant Pichia kudriavzevii by stimulating intracellular metabolism and inhibiting oxidative damage.
复制标题
盐胁迫通过刺激细胞内代谢和抑制氧化损伤来提高耐多重胁迫毕赤酵母的耐热性和高温生物乙醇产量
DOI：
10.1186/s13068-021-02071-0
复制
发表时间：
2021-11-25
影响因子：
6.3
通讯作者：
Li L
中科院分区：
文献类型：
--
作者：
Li C;Liu Q;Wang Y;Yang X;Chen S;Zhao Y;Wu Y;Li L
背景
高温生物乙醇生产受益于酵母耐热性。盐胁迫能诱导库氏毕赤酵母对热胁迫产生明显的交叉保护作用，有助于提高其耐热性和生物乙醇发酵能力。然而，交叉保护的基本机制仍然知之甚少。
结果
从生物量、细胞形态和产乙醇能力等方面观察，盐胁迫对库氏原盖菇的耐热性和高温产乙醇能力具有明显的交叉保护作用。在45 °C下，300 mmol/L NaCl处理使库氏毕赤酵母的生物量和乙醇产量分别提高了2.6倍和3.9倍。代谢网络图显示，盐胁迫明显提高了碳水化合物代谢的关键酶和中间产物，促进了生物乙醇、ATP、氨基酸、核苷酸和不饱和脂肪酸的合成以及随后的细胞内代谢。海藻糖、甘油、热休克蛋白和麦角固醇的增加有助于维持细胞组分的正常功能。热胁迫诱导了严重的氧化应激，随着培养温度从30 ° C升高到45 °C，ROS阳性细胞率和死亡细胞率分别从0.5%和2.4%上升到28.2%和69.2%。盐胁迫明显抑制了热诱导的活性氧爆发、氧化损伤和细胞死亡，尤其是在300 mmol/L NaCl胁迫下，细胞死亡率仅为20.3%。GSH和GST的大量合成是抑制氧化损伤的主要原因，300 mmol/LNaCl处理后GSH和GST的合成分别增加了4.8倍和76.1倍。乙醇产量的提高不仅是由于耐温性的提高，而且是由于盐胁迫导致乙醇脱氢酶的上调和乙醛脱氢酶的下调。
结论
研究结果首次揭示了盐胁迫提高库氏毕赤酵母耐热性和高温生物乙醇产量的机制，为构建高温生物乙醇生产基因工程酵母提供了重要信息。
图形摘要
Background
High-temperature bioethanol production benefits from yeast thermotolerance. Salt stress could induce obvious cross-protection against heat stress of Pichia kudriavzevii, contributing to the improvement of its thermotolerance and bioethanol fermentation. However, the underlying mechanisms of the cross-protection remain poorly understood.
Results
Salt stress showed obvious cross-protection for thermotolerance and high-temperature ethanol production of P. kudriavzevii observed by biomass, cell morphology and bioethanol production capacity. The biomass and ethanol production of P. kudriavzevii at 45 °C were, respectively, improved by 2.6 and 3.9 times by 300 mmol/L NaCl. Metabolic network map showed that salt stress obviously improved the key enzymes and intermediates in carbohydrate metabolism, contributing to the synthesis of bioethanol, ATP, amino acids, nucleotides, and unsaturated fatty acids, as well as subsequent intracellular metabolisms. The increasing trehalose, glycerol, HSPs, and ergosterol helped maintain the normal function of cell components. Heat stress induced serious oxidative stress that the ROS-positive cell rate and dead cell rate, respectively, rose from 0.5% and 2.4% to 28.2% and 69.2%, with the incubation temperature increasing from 30 to 45 °C. The heat-induced ROS outburst, oxidative damage, and cell death were obviously inhibited by salt stress, especially the dead cell rate which fell to only 20.3% at 300 mmol/L NaCl. The inhibiting oxidative damage mainly resulted from the abundant synthesis of GSH and GST, which, respectively, increased by 4.8 and 76.1 times after addition of 300 mmol/L NaCl. The improved bioethanol production was not only due to the improved thermotolerance, but resulted from the up-regulated alcohol dehydrogenases and down-regulated aldehyde dehydrogenases by salt stress.
Conclusion
The results provide a first insight into the mechanisms of the improved thermotolerance and high-temperature bioethanol production of P. kudriavzevii by salt stress, and provide important information to construct genetic engineering yeasts for high-temperature bioethanol production.
Graphical Abstract
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影响因子：
6.3
作者：
Romero-Frasca E;Velasquez-Orta SB;Escobar-Sánchez V;Tinoco-Valencia R;Orta Ledesma MT
通讯作者：
Orta Ledesma MT
影响因子：
11.4
作者：
Dhaliwal, Sandeep Singh;Oberoi, Harinder Singh;Uppal, Satinder Kaur
通讯作者：
Uppal, Satinder Kaur
影响因子：
11.2
作者：
Caspeta, Luis;Caro-Bermudez, Mario A.;Martinez, Alfredo
通讯作者：
Martinez, Alfredo
影响因子：
5.4
作者：
Dempfle, David;Krocher, Oliver;Studer, Michael Hans-Peter
通讯作者：
Studer, Michael Hans-Peter
影响因子：
6.4
作者：
Caspeta L;Nielsen J
通讯作者：
Nielsen J