scholarly journals Engineering Escherichia coli to synthesize free fatty acids

2012 ◽  
Vol 30 (12) ◽  
pp. 659-667 ◽  
Author(s):  
Rebecca M. Lennen ◽  
Brian F. Pfleger
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Free Fatty Acids

scholarly journals Genome-scale target identification in Escherichia coli for high-titer production of free fatty acids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lixia Fang ◽  
Jie Fan ◽  
Shulei Luo ◽  
Yaru Chen ◽  
Congya Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Free Fatty Acids ◽  
Stress Responses ◽  
Metabolic Networks ◽  
Target Identification ◽  
High Titer ◽  
Cell Factory ◽  
Microbial Cell Factory ◽  
Ffa Metabolism

AbstractTo construct a superior microbial cell factory for chemical synthesis, a major challenge is to fully exploit cellular potential by identifying and engineering beneficial gene targets in sophisticated metabolic networks. Here, we take advantage of CRISPR interference (CRISPRi) and omics analyses to systematically identify beneficial genes that can be engineered to promote free fatty acids (FFAs) production in Escherichia coli. CRISPRi-mediated genetic perturbation enables the identification of 30 beneficial genes from 108 targets related to FFA metabolism. Then, omics analyses of the FFAs-overproducing strains and a control strain enable the identification of another 26 beneficial genes that are seemingly irrelevant to FFA metabolism. Combinatorial perturbation of four beneficial genes involving cellular stress responses results in a recombinant strain ihfAL−-aidB+-ryfAM−-gadAH−, producing 30.0 g L−1 FFAs in fed-batch fermentation, the maximum titer in E. coli reported to date. Our findings are of help in rewiring cellular metabolism and interwoven intracellular processes to facilitate high-titer production of biochemicals.

scholarly journals Genome-wide targets identification by CRISPRi-Omics for high-titer production of free fatty acids in Escherichia coli

2020 ◽  
Author(s):  
Lixia Fang ◽  
Jie Fan ◽  
Congya Wang ◽  
Yingxiu Cao ◽  
Hao Song
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Free Fatty Acids ◽  
Metabolic Networks ◽  
High Titer ◽  
Cell Structure ◽  
Cell Factory ◽  
Microbial Cell Factory ◽  
Cell Potential ◽  
E Coli

AbstractTo construct a superior microbial cell factory for chemical synthesis, a major challenge is to fully exploit cell potential via identifying and engineering beneficial gene targets in the sophisticated metabolic networks. Here, we develop an approach that integrates CRISPR interference (CRISPRi) to readily modulate genes expression and omics analyses to identify potential targets in multiple cellular processes, enabling systematical discovery of beneficial chromosomal gene targets that can be engineered to optimize free fatty acids (FFAs) production in Escherichia coli. We identify 56 beneficial genes via synergistic CRISPRi-Omics strategy, including 46 novel targets functioning in cell structure and division, and signaling transduction that efficiently facilitate FFAs production. Upon repressing ihfA and overexpressing aidB and tesA’ in E. coli, the recombinant strain LihfA-OaidB results in a FFAs titer of 21.6 g L-1 in fed-batch fermentation, which, to our best knowledge, is the maximum FFAs titer by the recombinant E. coli reported to date.

Production of free fatty acids from switchgrass using recombinant Escherichia coli

2017 ◽  
Vol 34 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Jung-Eun Lee ◽  
Praveen V. Vadlani ◽  
Yadhu N. Guragain ◽  
Ka-Yiu San ◽  
Doo-Hong Min
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Free Fatty Acids ◽  
Recombinant Escherichia Coli

scholarly journals Membrane Stresses Induced by Overproduction of Free Fatty Acids in Escherichia coli

2011 ◽  
Vol 77 (22) ◽  
pp. 8114-8128 ◽  
Author(s):  
Rebecca M. Lennen ◽  
Max A. Kruziki ◽  
Kritika Kumar ◽  
Robert A. Zinkel ◽  
Kristin E. Burnum ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Unsaturated Fatty Acid ◽  
High Energy ◽  
High Energy Density ◽  
Content Type ◽  
E Coli ◽  
Expression Of Genes

ABSTRACTMicrobially produced fatty acids are potential precursors to high-energy-density biofuels, including alkanes and alkyl ethyl esters, by either catalytic conversion of free fatty acids (FFAs) or enzymatic conversion of acyl-acyl carrier protein or acyl-coenzyme A intermediates. Metabolic engineering efforts aimed at overproducing FFAs inEscherichia colihave achieved less than 30% of the maximum theoretical yield on the supplied carbon source. In this work, the viability, morphology, transcript levels, and protein levels of a strain ofE. colithat overproduces medium-chain-length FFAs was compared to an engineered control strain. By early stationary phase, an 85% reduction in viable cell counts and exacerbated loss of inner membrane integrity were observed in the FFA-overproducing strain. These effects were enhanced in strains endogenously producing FFAs compared to strains exposed to exogenously fed FFAs. Under two sets of cultivation conditions, long-chain unsaturated fatty acid content greatly increased, and the expression of genes and proteins required for unsaturated fatty acid biosynthesis were significantly decreased. Membrane stresses were further implicated by increased expression of genes and proteins of the phage shock response, the MarA/Rob/SoxS regulon, and thenuoandcyooperons of aerobic respiration. Gene deletion studies confirmed the importance of the phage shock proteins and Rob for maintaining cell viability; however, little to no change in FFA titer was observed after 24 h of cultivation. The results of this study serve as a baseline for future targeted attempts to improve FFA yields and titers inE. coli.

Tumor necrosis factor is a mediator of phospholipase release during bacteremia in baboons

1993 ◽  
Vol 264 (6) ◽  
pp. H2119-H2123 ◽  
Author(s):  
H. Redl ◽  
G. Schlag ◽  
A. Schiesser ◽  
J. Davies
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Tumor Necrosis Factor ◽  
Free Fatty Acids ◽  
Tumor Necrosis ◽  
Phospholipase A ◽  
Primate Model ◽  
Important Mediator ◽  
Colony Forming Units ◽  
Necrosis Factor

Phospholipase A (PLA) activity is elevated in plasma after polytrauma and in sepsis. During both situations, tumor necrosis factor (TNF) and free fatty acids (FFAs) are also increased. To determine whether there is a relationship between the changes in PLA and in TNF that occur during sepsis, we used a primate model of bacteremia. Live Escherichia coli (5 x 10(8) colony-forming units/kg) was injected into anesthetized baboons (n = 10). Four of these animals were pretreated with an anti-TNF antibody (anti-TNF Ab, 15 mg/kg). After the administration of bacteria (2 h), the plasma TNF was 10.2 +/- 3.2 ng/ml. PLA and FFA reached their maximum values of 191 +/- 14 U/l and 1.5 +/- 0.3 mM at 10 and 24 h after the injection of bacteria, respectively. In the animals treated with anti-TNF Ab, plasma TNF was undetectable; the highest values recorded for PLA and FFA were 71 +/- 23 U/l and 0.7 +/- 0.3 mM, respectively. Thus TNF appears to be an important mediator of PLA release during sepsis.

Engineering Escherichia coli to convert acetic acid to free fatty acids

2013 ◽  
Vol 76 ◽  
pp. 60-69 ◽  
Author(s):  
Yi Xiao ◽  
Zhenhua Ruan ◽  
Zhiguo Liu ◽  
Stephen G. Wu ◽  
Arul M. Varman ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Acetic Acid ◽  
Free Fatty Acids
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