Campus Units

Chemical and Biological Engineering

Document Type

Article

Research Focus Area

Biorenewables

Publication Version

Published Version

Publication Date

2-28-2017

Journal or Book Title

Microbial Cell Factories

Volume

16

Issue

1

First Page

38

DOI

10.1186/s12934-017-0650-8

Abstract

Background

Construction of microbial biocatalysts for the production of biorenewables at economically viable yields and titers is frequently hampered by product toxicity. Membrane damage is often deemed as the principal mechanism of this toxicity, particularly in regards to decreased membrane integrity. Previous studies have attempted to engineer the membrane with the goal of increasing membrane integrity. However, most of these works focused on engineering of phospholipids and efforts to identify membrane proteins that can be targeted to improve fatty acid production have been unsuccessful.

Results

Here we show that deletion of outer membrane protein ompF significantly increased membrane integrity, fatty acid tolerance and fatty acid production, possibly due to prevention of re-entry of short chain fatty acids. In contrast, deletion of fadL resulted in significantly decreased membrane integrity and fatty acid production. Consistently, increased expression of fadL remarkably increased membrane integrity and fatty acid tolerance while also increasing the final fatty acid titer. This 34% increase in the final fatty acid titer was possibly due to increased membrane lipid biosynthesis. Tuning of fadL expression showed that there is a positive relationship between fadL abundance and fatty acid production. Combinatorial deletion of ompFand increased expression of fadL were found to have an additive role in increasing membrane integrity, and was associated with a 53% increase the fatty acid titer, to 2.3 g/L.

Conclusions

These results emphasize the importance of membrane proteins for maintaining membrane integrity and production of biorenewables, such as fatty acids, which expands the targets for membrane engineering.

Comments

This article is published as Tan, Zaigao, William Black, Jong Moon Yoon, Jacqueline V. Shanks, and Laura R. Jarboe. "Improving Escherichia coli membrane integrity and fatty acid production by expression tuning of FadL and OmpF." Microbial cell factories 16, no. 1 (2017): 38. 10.1186/s12934-017-0650-8. Posted with permission.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Copyright Owner

The Authors

Language

en

File Format

application/pdf

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