Format

Send to

Choose Destination

See 1 citation found by title matching your search:

Metab Eng. 2016 Jan;33:28-40. doi: 10.1016/j.ymben.2015.10.010. Epub 2015 Nov 10.

Modular and selective biosynthesis of gasoline-range alkanes.

Author information

1
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
2
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Synthetic Biology Engineering Research Center (SynBERC), Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

Abstract

Typical renewable liquid fuel alternatives to gasoline are not entirely compatible with current infrastructure. We have engineered Escherichia coli to selectively produce alkanes found in gasoline (propane, butane, pentane, heptane, and nonane) from renewable substrates such as glucose or glycerol. Our modular pathway framework achieves carbon-chain extension by two different mechanisms. A fatty acid synthesis route is used to generate longer chains heptane and nonane, while a more energy efficient alternative, reverse-β-oxidation, is used for synthesis of propane, butane, and pentane. We demonstrate that both upstream (thiolase) and intermediate (thioesterase) reactions can act as control points for chain-length specificity. Specific free fatty acids are subsequently converted to alkanes using a broad-specificity carboxylic acid reductase and a cyanobacterial aldehyde decarbonylase (AD). The selectivity obtained by different module pairings provides a foundation for tuning alkane product distribution for desired fuel properties. Alternate ADs that have greater activity on shorter substrates improve observed alkane titer. However, even in an engineered host strain that significantly reduces endogenous conversion of aldehyde intermediates to alcohol byproducts, AD activity is observed to be limiting for all chain lengths. Given these insights, we discuss guiding principles for pathway selection and potential opportunities for pathway improvement.

KEYWORDS:

Alkanes; Biofuel; E. coli; Gasoline; Metabolic engineering; Synthetic biology

PMID:
26556131
DOI:
10.1016/j.ymben.2015.10.010
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center