Background: Glycerol is a major byproduct of the biodiesel industry and can be converted to 1,3-propanediol (1,3-PDO) by microorganisms through a two-step enzymatic reaction. The production of 1,3-PDO from glycerol using microorganisms is accompanied by formation of unwanted byproducts, including lactate and 2,3-butanediol, resulting in a low-conversion yield. Results: Klebsiella pneumoniae was metabolically engineered to produce high-molar yield of 1,3-PDO from glycerol. First, the pathway genes for byproduct formation were deleted in K. pneumoniae. Then, glycerol assimilation pathways were eliminated and mannitol was co-fed to the medium. Finally, transcriptional regulation of the dha operon were genetically modified for enhancing 1,3-propanediol production. The batch fermentation of the engineered strain with co-feeding of a small amount of mannitol yielded 0.76 mol 1,3-PDO from 1 mol glycerol. Conclusions: Klebsiella pneumoniae is useful microorganism for producing 1,3-PDO from glycerol. Implemented engineering in this study successfully improved 1,3-PDO production yield, which is significantly higher than those reported in previous studies.
Bibliographical noteFunding Information:
This study was supported by a grant from the New & Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning (No. 20143030091040); and a grant from the National Research Founda‑ tion of Korea funded by the Korean Government (2012M1A2A2026560 and 2015M3D3A1A01064919).
© 2018 The Author(s).
- 1, 3-PDO
- Glycerol assimilation pathway
- Klebsiella pneumoniae
- dha operon
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology
- Renewable Energy, Sustainability and the Environment
- Management, Monitoring, Policy and Law