Membrane engineering via trans unsaturated fatty acids production improves Escherichia coli robustness and production of biorenewables

Date
2016-05
Authors
Tan, Zaigao
Yoon, Jong Moon
Nielsen, David R.
Shanks, Jacqueline
Jarboe, Laura
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Altmetrics
Authors
Research Projects
Organizational Units
Microbiology
Organizational Unit
Journal Issue
Series
Department
Chemical and Biological EngineeringBioinformatics and Computational BiologyMicrobiology
Abstract
Constructing microbial biocatalysts that produce biorenewables at economically viable yields and titers is often hampered by product toxicity. For production of short chain fatty acids, membrane damage is considered the primary mechanism of toxicity, particularly in regards to membrane integrity. Previous engineering efforts in Escherichia coli to increase membrane integrity, with the goal of increasing fatty acid tolerance and production, have had mixed results. Herein, a novel approach was used to reconstruct the E. coli membrane by enabling production of a novel membrane component. Specifically, trans unsaturated fatty acids (TUFA) were produced and incorporated into the membrane of E. coli MG1655 by expression of cis-trans isomerase (Cti) from Pseudomonas aeruginosa. While the engineered strain was found to have no increase in membrane integrity, a significant decrease in membrane fluidity was observed, meaning that membrane polarization and rigidity were increased by TUFA incorporation. As a result, tolerance to exogenously added octanoic acid and production of octanoic acid were both increased relative to the wild-type strain. This membrane engineering strategy to improve octanoic acid tolerance was found to require fine-tuning of TUFA abundance. Besides improving tolerance and production of carboxylic acids, TUFA production also enabled increased tolerance in E. coli to other bio-products, e.g. alcohols, organic acids, aromatic compounds, a variety of adverse industrial conditions, e.g. low pH, high temperature, and also elevated styrene production, another versatile bio-chemical product. TUFA permitted enhanced growth due to alleviation of bio–product toxicity, demonstrating the general effectiveness of this membrane engineering strategy towards improving strain robustness.
Comments
This is a manuscript of an article published as Tan, Zaigao, Jong Moon Yoon, David R. Nielsen, Jacqueline V. Shanks, and Laura R. Jarboe. "Membrane engineering via trans unsaturated fatty acids production improves Escherichia coli robustness and production of biorenewables." Metabolic Engineering 35 (2016): 105-113. DOI: 10.1016/j.ymben.2016.02.004. Copyright 2016 International Metabolic Engineering Society. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0). Posted with permission.
Description
Keywords
Trans unsaturated fatty acids (TUFA), Tolerance, Membrane fluidity, Membrane integrity, Carboxylic acids production
Citation
DOI
Collections