Modulating membrane composition alters free fatty acid tolerance in Escherichia coli.
Modulating membrane composition alters free fatty acid tolerance in Escherichia coli.
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DOI：
10.1371/journal.pone.0054031
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Pfleger BF
中科院分区：
文献类型：
--
作者：
Lennen RM;Pfleger BF
微生物合成游离脂肪酸（FFA）是将可再生糖转化为先进生物燃料和油脂化学品的一种有前途的策略。不幸的是，FFA生产负面影响膜完整性和细胞活力在大肠杆菌，FFA生产的主要宿主中进行了研究。这些负面影响对FFA生产提供了选择性压力，这可能导致工业规模的遗传不稳定性。在先前的工作中，工程E。含有加州伞形藻酰基-酰基载体蛋白（ACP）硫酯酶表达质粒的大肠杆菌菌株显示在细胞膜中具有高度升高的不饱和脂肪酸水平。假设膜含量的变化是与FFA产生相关的负面生理效应的一个根本原因。本研究将不饱和脂肪酸生物合成调控因子与大肠杆菌中不饱和脂肪酸生物合成调控因子之间的关系进行了初步探讨。coli、FabR、硫酯酶表达和不饱和膜含量。通过用主要靶向中链长度、不饱和酰基-ACP的第二硫酯酶（来自Geobacillus sp.Y412MC10）调节酰基-ACP池来实施用于恢复正常膜饱和水平和增加对内源性FFA产生的耐受性的策略。该策略成功地恢复了膜含量，提高了FFA生产E.大肠杆菌，同时保持FFA滴度。然而，恢复健身并没有增加FFA的生产力，表明存在额外的代谢或监管障碍。
Microbial synthesis of free fatty acids (FFA) is a promising strategy for converting renewable sugars to advanced biofuels and oleochemicals. Unfortunately, FFA production negatively impacts membrane integrity and cell viability in Escherichia coli, the dominant host in which FFA production has been studied. These negative effects provide a selective pressure against FFA production that could lead to genetic instability at industrial scale. In prior work, an engineered E. coli strain harboring an expression plasmid for the Umbellularia californica acyl-acyl carrier protein (ACP) thioesterase was shown to have highly elevated levels of unsaturated fatty acids in the cell membrane. The change in membrane content was hypothesized to be one underlying cause of the negative physiological effects associated with FFA production. In this work, a connection between the regulator of unsaturated fatty acid biosynthesis in E. coli, FabR, thioesterase expression, and unsaturated membrane content was established. A strategy for restoring normal membrane saturation levels and increasing tolerance towards endogenous production of FFAs was implemented by modulating acyl-ACP pools with a second thioesterase (from Geobacillus sp. Y412MC10) that primarily targets medium chain length, unsaturated acyl-ACPs. The strategy succeeded in restoring membrane content and improving viability in FFA producing E. coli while maintaining FFA titers. However, the restored fitness did not increase FFA productivity, indicating the existence of additional metabolic or regulatory barriers.
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影响因子：
8.4
作者：
Agnew, Daniel E.;Stevermer, Amanda K.;Youngquist, J. Tyler;Pfleger, Brian F.
通讯作者：
Pfleger, Brian F.
影响因子：
8.4
作者：
Lu, Xuefeng;Vora, Harmit;Khosla, Chaitan
通讯作者：
Khosla, Chaitan
影响因子：
3.5
作者：
CHEREPANOV, PP;WACKERNAGEL, W
通讯作者：
WACKERNAGEL, W
影响因子：
2.8
作者：
Khlebnikov, A;Datsenko, KA;Keasling, JD
通讯作者：
Keasling, JD
影响因子：
11.6
作者：
JONES, A;DAVIES, HM;VOELKER, TA
通讯作者：
VOELKER, TA