Improved bioproduction of 1-octanol using engineered Synechocystis sp. PCC 6803
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
1-Octanol has gained interest as a chemical precursor for both high and low value commodities including fuel, solvents, surfactants, and fragrances. By harnessing the power from sunlight and CO2 as carbon source, cyanobacteria has recently been engineered for renewable production of 1-octanol. The productivity, however, remained low. In the present work, we report efforts to further improve the 1-octanol productivity. Different N-terminal truncations were evaluated on three thioesterases from different plant species, resulting in several candidate thioesterases with improved activity and selectivity toward octanoyl-ACP. The structure/function trials suggest that current knowledge and/or state-of-the art computational tools are insufficient to determine the most appropriate cleavage site for thioesterases in Synechocystis. Additionally, by tuning the inducer concentration and light intensity, we further improved the 1-octanol productivity, reaching up to 35% (w/w) carbon partitioning and a titer of 526 ± 5 mg/L 1-octanol in 12 days. Long-term cultivation experiments demonstrated that the improved strain can be stably maintained for at least 30 days and/or over ten times serial dilution. Surprisingly, the improved strain was genetically stable in contrast to earlier strains having lower productivity (and hence a reduced chance of reaching toxic product concentrations). Altogether, improved enzymes and environmental conditions (e.g., inducer concentration and light intensity) substantially increased the 1-octanol productivity. When cultured under continuous conditions, the bioproduction system reached an accumulative titer of >3.5 g/L 1-octanol over close to 180 days.
Date Issued
2021-06-18
Date Acceptance
2021-05-01
Citation
ACS Synthetic Biology, 2021, 10 (6), pp.1417-1428
ISSN
2161-5063
Publisher
American Chemical Society
Start Page
1417
End Page
1428
Journal / Book Title
ACS Synthetic Biology
Volume
10
Issue
6
Copyright Statement
Copyright © 2021 American Chemical Society.
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/34003632
Subjects
Biochemical Research Methods
Biochemistry & Molecular Biology
biofuels
BIOFUELS
BIOMASS PRODUCTION
BIOSYNTHESIS
CARBON-DIOXIDE
cyanobacteria
CYANOBACTERIA
fatty alcohols
FATTY-ACIDS PRODUCTION
fragrance
free fatty acids
FUELS
Life Sciences & Biomedicine
LIGHT-INTENSITY
metabolic engineering
MICROBIAL-PRODUCTION
Science & Technology
thioesterase
THIOESTERASES
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2021-05-18