Enhanced Butanol Production Obtained by Reinforcing the Direct Butanol-Forming Route in Clostridium acetobutylicum

Butanol is an important industrial solvent and advanced biofuel that can be produced by biphasic fermentation by Clostridium acetobutylicum. It has been known that acetate and butyrate first formed during the acidogenic phase are reassimilated to form acetone-butanol-ethanol (cold channel). Butanol...

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Main Authors:	Jang, Yu-Sin, Lee, Jin Young, Lee, Joungmin, Park, Jin Hwan, Im, Jung Ae, Eom, Moon-Ho, Lee, Julia, Lee, Sang-Hyun, Song, Hyohak, Cho, Jung-Hee, Seung, Do Young, Lee, Sang Yup
Format:	Online
Language:	English
Published:	American Society of Microbiology 2012
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3482502/

id	pubmed-3482502
recordtype	oai_dc
spelling	pubmed-34825022012-10-28 Enhanced Butanol Production Obtained by Reinforcing the Direct Butanol-Forming Route in Clostridium acetobutylicum Jang, Yu-Sin Lee, Jin Young Lee, Joungmin Park, Jin Hwan Im, Jung Ae Eom, Moon-Ho Lee, Julia Lee, Sang-Hyun Song, Hyohak Cho, Jung-Hee Seung, Do Young Lee, Sang Yup Research Article Butanol is an important industrial solvent and advanced biofuel that can be produced by biphasic fermentation by Clostridium acetobutylicum. It has been known that acetate and butyrate first formed during the acidogenic phase are reassimilated to form acetone-butanol-ethanol (cold channel). Butanol can also be formed directly from acetyl-coenzyme A (CoA) through butyryl-CoA (hot channel). However, little is known about the relative contributions of the two butanol-forming pathways. Here we report that the direct butanol-forming pathway is a better channel to optimize for butanol production through metabolic flux and mass balance analyses. Butanol production through the hot channel was maximized by simultaneous disruption of the pta and buk genes, encoding phosphotransacetylase and butyrate kinase, while the adhE1D485G gene, encoding a mutated aldehyde/alcohol dehydrogenase, was overexpressed. The ratio of butanol produced through the hot channel to that produced through the cold channel increased from 2.0 in the wild type to 18.8 in the engineered BEKW(pPthlAAD**) strain. By reinforcing the direct butanol-forming flux in C. acetobutylicum, 18.9 g/liter of butanol was produced, with a yield of 0.71 mol butanol/mol glucose by batch fermentation, levels which are 160% and 245% higher than those obtained with the wild type. By fed-batch culture of this engineered strain with in situ recovery, 585.3 g of butanol was produced from 1,861.9 g of glucose, with the yield of 0.76 mol butanol/mol glucose and productivity of 1.32 g/liter/h. Studies of two butanol-forming routes and their effects on butanol production in C. acetobutylicum described here will serve as a basis for further metabolic engineering of clostridia aimed toward developing a superior butanol producer. American Society of Microbiology 2012-10-23 /pmc/articles/PMC3482502/ /pubmed/23093384 http://dx.doi.org/10.1128/mBio.00314-12 Text en Copyright © 2012 Jang et al. http://creativecommons.org/licenses/by-nc-sa/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License (http://creativecommons.org/licenses/by-nc-sa/3.0/) , which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original author and source are credited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Jang, Yu-Sin Lee, Jin Young Lee, Joungmin Park, Jin Hwan Im, Jung Ae Eom, Moon-Ho Lee, Julia Lee, Sang-Hyun Song, Hyohak Cho, Jung-Hee Seung, Do Young Lee, Sang Yup
spellingShingle	Jang, Yu-Sin Lee, Jin Young Lee, Joungmin Park, Jin Hwan Im, Jung Ae Eom, Moon-Ho Lee, Julia Lee, Sang-Hyun Song, Hyohak Cho, Jung-Hee Seung, Do Young Lee, Sang Yup Enhanced Butanol Production Obtained by Reinforcing the Direct Butanol-Forming Route in Clostridium acetobutylicum
author_facet	Jang, Yu-Sin Lee, Jin Young Lee, Joungmin Park, Jin Hwan Im, Jung Ae Eom, Moon-Ho Lee, Julia Lee, Sang-Hyun Song, Hyohak Cho, Jung-Hee Seung, Do Young Lee, Sang Yup
author_sort	Jang, Yu-Sin
title	Enhanced Butanol Production Obtained by Reinforcing the Direct Butanol-Forming Route in Clostridium acetobutylicum
title_short	Enhanced Butanol Production Obtained by Reinforcing the Direct Butanol-Forming Route in Clostridium acetobutylicum
title_full	Enhanced Butanol Production Obtained by Reinforcing the Direct Butanol-Forming Route in Clostridium acetobutylicum
title_fullStr	Enhanced Butanol Production Obtained by Reinforcing the Direct Butanol-Forming Route in Clostridium acetobutylicum
title_full_unstemmed	Enhanced Butanol Production Obtained by Reinforcing the Direct Butanol-Forming Route in Clostridium acetobutylicum
title_sort	enhanced butanol production obtained by reinforcing the direct butanol-forming route in clostridium acetobutylicum
description	Butanol is an important industrial solvent and advanced biofuel that can be produced by biphasic fermentation by Clostridium acetobutylicum. It has been known that acetate and butyrate first formed during the acidogenic phase are reassimilated to form acetone-butanol-ethanol (cold channel). Butanol can also be formed directly from acetyl-coenzyme A (CoA) through butyryl-CoA (hot channel). However, little is known about the relative contributions of the two butanol-forming pathways. Here we report that the direct butanol-forming pathway is a better channel to optimize for butanol production through metabolic flux and mass balance analyses. Butanol production through the hot channel was maximized by simultaneous disruption of the pta and buk genes, encoding phosphotransacetylase and butyrate kinase, while the adhE1D485G gene, encoding a mutated aldehyde/alcohol dehydrogenase, was overexpressed. The ratio of butanol produced through the hot channel to that produced through the cold channel increased from 2.0 in the wild type to 18.8 in the engineered BEKW(pPthlAAD**) strain. By reinforcing the direct butanol-forming flux in C. acetobutylicum, 18.9 g/liter of butanol was produced, with a yield of 0.71 mol butanol/mol glucose by batch fermentation, levels which are 160% and 245% higher than those obtained with the wild type. By fed-batch culture of this engineered strain with in situ recovery, 585.3 g of butanol was produced from 1,861.9 g of glucose, with the yield of 0.76 mol butanol/mol glucose and productivity of 1.32 g/liter/h. Studies of two butanol-forming routes and their effects on butanol production in C. acetobutylicum described here will serve as a basis for further metabolic engineering of clostridia aimed toward developing a superior butanol producer.
publisher	American Society of Microbiology
publishDate	2012
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3482502/
_version_	1611919329205420032

Enhanced Butanol Production Obtained by Reinforcing the Direct Butanol-Forming Route in Clostridium acetobutylicum

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