Improving Escherichia coli membrane integrity and fatty acid production by expression tuning of FadL and OmpF
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The function of the Department of Chemical and Biological Engineering has been to prepare students for the study and application of chemistry in industry. This focus has included preparation for employment in various industries as well as the development, design, and operation of equipment and processes within industry.Through the CBE Department, Iowa State University is nationally recognized for its initiatives in bioinformatics, biomaterials, bioproducts, metabolic/tissue engineering, multiphase computational fluid dynamics, advanced polymeric materials and nanostructured materials.
History
The Department of Chemical Engineering was founded in 1913 under the Department of Physics and Illuminating Engineering. From 1915 to 1931 it was jointly administered by the Divisions of Industrial Science and Engineering, and from 1931 onward it has been under the Division/College of Engineering. In 1928 it merged with Mining Engineering, and from 1973–1979 it merged with Nuclear Engineering. It became Chemical and Biological Engineering in 2005.
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1913 - present
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- Department of Chemical Engineering (1913–1928)
- Department of Chemical and Mining Engineering (1928–1957)
- Department of Chemical Engineering (1957–1973, 1979–2005)
- Department of Chemical and Biological Engineering (2005–present)
- College of Engineering(parent college)
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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.