Journal article
Endogenous carbohydrate esterases of Clostridium thermocellum are identified and disrupted for enhanced isobutyl acetate production from cellulose
Biotechnology and bioengineering, Vol.117(7), pp.2223-2236
07/2020
DOI: 10.1002/bit.27360
PMID: 32333614
Abstract
Medium-chain esters are versatile chemicals with broad applications as flavors, fragrances, solvents, and potential drop-in biofuels. Currently, these esters are largely produced by the conventional chemical process that uses harsh operating conditions and requires high energy input. Alternatively, the microbial conversion route has recently emerged as a promising platform for sustainable and renewable ester production. The ester biosynthesis pathways can utilize either lipases or alcohol acyltransferase (AAT), but the AAT-dependent pathway is more thermodynamically favorable in an aqueous fermentation environment. Even though a cellulolytic thermophile Clostridium thermocellum harboring an AAT-dependent pathway has recently been engineered for direct conversion of lignocellulosic biomass into esters, the production is not efficient. One potential bottleneck is the ester degradation caused by the endogenous carbohydrate esterases (CEs) whose functional roles are poorly understood. The challenge is to identify and disrupt CEs that can alleviate ester degradation while not negatively affecting the efficient and robust capability of C. thermocellum for lignocellulosic biomass deconstruction. In this study, by using bioinformatics, comparative genomics, and enzymatic analysis to screen a library of CEs, we identified and disrupted the two most critical CEs, Clo1313_0613 and Clo1313_0693, that significantly contribute to isobutyl acetate degradation in C. thermocellum. We demonstrated that an engineered esterase-deficient C. thermocellum strain not only reduced ester hydrolysis but also improved isobutyl acetate production while maintaining effective cellulose assimilation.
Details
- Title: Subtitle
- Endogenous carbohydrate esterases of Clostridium thermocellum are identified and disrupted for enhanced isobutyl acetate production from cellulose
- Creators
- Hyeongmin Seo - University of Tennessee at KnoxvillePreston N. Nicely - University of Tennessee at KnoxvilleCong T. Trinh - University of Tennessee at Knoxville
- Resource Type
- Journal article
- Publication Details
- Biotechnology and bioengineering, Vol.117(7), pp.2223-2236
- Publisher
- Wiley
- DOI
- 10.1002/bit.27360
- PMID
- 32333614
- ISSN
- 0006-3592
- eISSN
- 1097-0290
- Number of pages
- 14
- Grant note
- 1553250 / NSF; National Science Foundation (NSF) US National Science Foundation; National Science Foundation (NSF) DE-AC05-00OR22725 / US Department of Energy; United States Department of Energy (DOE)
- Language
- English
- Date published
- 07/2020
- Academic Unit
- Chemical and Biochemical Engineering
- Record Identifier
- 9984696565702771
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