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Title: Conversion of ammonia-pretreated switchgrass to biofuel precursors by bacterial-fungal consortia under solid-state and submerged-state cultivation

Authors:
 [1];  [2];  [3];  [4]
  1. Biotechnology Institute, University of Minnesota, Twin Cities Falcon Heights MN USA
  2. Department of Biology, Sacred Heart University, Fairfield CT USA
  3. University of South Carolina School of Law, Columbia SC USA
  4. Department of Biological Sciences, Clemson University, Clemson SC USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1401476
Grant/Contract Number:
FG36-08GO88071
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Applied Microbiology
Additional Journal Information:
Journal Volume: 122; Journal Issue: 4; Related Information: CHORUS Timestamp: 2017-10-20 16:59:10; Journal ID: ISSN 1364-5072
Publisher:
Wiley-Blackwell
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Jain, A., Pelle, H. S., Baughman, W. H., and Henson, J. M. Conversion of ammonia-pretreated switchgrass to biofuel precursors by bacterial-fungal consortia under solid-state and submerged-state cultivation. United Kingdom: N. p., 2017. Web. doi:10.1111/jam.13295.
Jain, A., Pelle, H. S., Baughman, W. H., & Henson, J. M. Conversion of ammonia-pretreated switchgrass to biofuel precursors by bacterial-fungal consortia under solid-state and submerged-state cultivation. United Kingdom. doi:10.1111/jam.13295.
Jain, A., Pelle, H. S., Baughman, W. H., and Henson, J. M. Mon . "Conversion of ammonia-pretreated switchgrass to biofuel precursors by bacterial-fungal consortia under solid-state and submerged-state cultivation". United Kingdom. doi:10.1111/jam.13295.
@article{osti_1401476,
title = {Conversion of ammonia-pretreated switchgrass to biofuel precursors by bacterial-fungal consortia under solid-state and submerged-state cultivation},
author = {Jain, A. and Pelle, H. S. and Baughman, W. H. and Henson, J. M.},
abstractNote = {},
doi = {10.1111/jam.13295},
journal = {Journal of Applied Microbiology},
number = 4,
volume = 122,
place = {United Kingdom},
year = {Mon Feb 27 00:00:00 EST 2017},
month = {Mon Feb 27 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1111/jam.13295

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  • Biological production of chemicals and fuels using microbial transformation of sustainable carbon sources, such as pretreated and saccharified plant biomass, is a multi-step process. Typically, each segment of the workflow is optimized separately, often generating conditions that may not be suitable for integration or consolidation with the upstream or downstream steps. While significant effort has gone into developing solutions to incompatibilities at discrete steps, very few studies report the consolidation of the multi-step workflow into a single pot reactor system. Here we demonstrate a one-pot biofuel production process that uses the ionic liquid 1-ethyl-3-methylimidazolium acetate (C 2C 1Im][OAc] ) formore » pretreatment of switchgrass biomass. [C 2C 1Im][OAc] is highly effective in deconstructing lignocellulose, but nonetheless leaves behind residual reagents that are toxic to standard saccharification enzymes and the microbial production host. We report the discovery of an [C 2C 1Im]-tolerant E. coli strain, where [C 2C 1Im] tolerance is bestowed by a P7Q mutation in the transcriptional regulator encoded by rcdA. We establish that the causal impact of this mutation is the derepression of a hitherto uncharacterized major facilitator family transporter, YbjJ. To develop the strain for a one-pot process we engineered this [C 2C 1Im]-tolerant strain to express a recently reported d-limonene production pathway. We also screened previously reported [C 2C 1Im]-tolerant cellulases to select one that would function with the range of E. coli cultivation conditions and expressed it in the [C 2C 1 Im]-tolerant E. coli strain so as to secrete this [C 2C 1Im]-tolerant cellulase. The final strain digests pretreated biomass, and uses the liberated sugars to produce the bio-jet fuel candidate precursor d-limonene in a one-pot process.« less
  • Industrial-scale biofuel production requires robust enzymatic cocktails to produce fermentable sugars from lignocellulosic biomass. Thermophilic bacterial consortia are a potential source of cellulases and hemicellulases adapted to harsher reaction conditions than commercial fungal enzymes. Compost-derived microbial consortia were adapted to switchgrass at 60 C to develop thermophilic biomass-degrading consortia for detailed studies. Microbial community analysis using small-subunit rRNA gene amplicon pyrosequencing and short-read metagenomic sequencing demonstrated that thermophilic adaptation to switchgrass resulted in low-diversity bacterial consortia with a high abundance of bacteria related to thermophilic paenibacilli, Rhodothermus marinus, and Thermus thermophilus. At lower abundance, thermophilic Chloroflexi and an uncultivated lineagemore » of the Gemmatimonadetes phylum were observed. Supernatants isolated from these consortia had high levels of xylanase and endoglucanase activities. Compared to commercial enzyme preparations, the endoglucanase enzymes had a higher thermotolerance and were more stable in the presence of 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), an ionic liquid used for biomass pretreatment. The supernatants were used to saccharify [C2mim][OAc]-pretreated switchgrass at elevated temperatures (up to 80 C), demonstrating that these consortia are an excellent source of enzymes for the development of enzymatic cocktails tailored to more extreme reaction conditions.« less