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Title: Guanidine Riboswitch-Regulated Efflux Transporters Protect Bacteria against Ionic Liquid Toxicity

Journal Article · · Journal of Bacteriology
 [1];  [2]; ORCiD logo [3];  [4];  [4]; ORCiD logo [1]
  1. Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
+ Show Author Affiliations

Plant cell walls contain a renewable, nearly limitless supply of sugar that could be used to support microbial production of commodity chemicals and biofuels. Imidazolium ionic liquid (IIL) solvents are among the best reagents for gaining access to the sugars in this otherwise recalcitrant biomass. However, the sugars from IIL-treated biomass are inevitably contaminated with residual IILs that inhibit growth in bacteria and yeast, blocking biochemical production by these organisms. IIL toxicity is, therefore, a critical roadblock in many industrial biosynthetic pathways. Although several IIL-tolerant (IILT) bacterial and yeast isolates have been identified in nature, few genetic mechanisms have been identified. In this study, we identified two IILT Bacillus isolates as well as a spontaneous IILT Escherichia coli lab strain that are tolerant to high levels of two widely used IILs. We demonstrate that all three IILT strains contain one or more pumps of the small multidrug resistance (SMR) family, and two of these strains contain mutations that affect an adjacent regulatory guanidine riboswitch. Furthermore, we show that the regulation of E. coli sugE by the guanidine II riboswitch can be exploited to promote IIL tolerance by the simple addition of guanidine to the medium. Our results demonstrate the critical role that transporter genes play in IIL tolerance in their native bacterial hosts. The study presented here is another step in engineering IIL tolerance into industrial strains toward overcoming this key gap in biofuels and industrial biochemical production processes.

Research Organization:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
AC52-07NA27344
OSTI ID:
1544473
Report Number(s):
LLNL-JRNL-767148; 957444
Journal Information:
Journal of Bacteriology, Vol. 201, Issue 13; ISSN 0021-9193
Publisher:
American Society for MicrobiologyCopyright Statement
Country of Publication:
United States
Language:
English

References (49)

Designing tailored microbial and enzymatic response in ionic liquids for lignocellulosic biorefineries journal April 2018
Comparison of enzymatic reactivity of corn stover solids prepared by dilute acid, AFEX™, and ionic liquid pretreatments journal January 2014
Visualization of biomass solubilization and cellulose regeneration during ionic liquid pretreatment of switchgrass journal September 2009
Comparison of dilute acid and ionic liquid pretreatment of switchgrass: Biomass recalcitrance, delignification and enzymatic saccharification journal July 2010
Lignin Depletion Enhances the Digestibility of Cellulose in Cultured Xylem Cells journal July 2013
Biomass deconstruction to sugars journal August 2011
Efficient biomass pretreatment using ionic liquids derived from lignin and hemicellulose journal August 2014
Emergence of resistance to antibacterial agents: the role of quaternary ammonium compounds—a critical review journal May 2012
Complete genome sequence of “Enterobacter lignolyticus” SCF1 journal September 2011
Global transcriptome response to ionic liquid by a tropical rain forest soil bacterium, Enterobacter lignolyticus journal May 2012
Isolation and Characterisation of 1-Alkyl-3-Methylimidazolium Chloride Ionic Liquid-Tolerant and Biodegrading Marine Bacteria journal April 2013
Draft Genome Sequence of the Ionic Liquid-Tolerant Bacterium Bacillus amyloliquefaciens CMW1 journal September 2014
Bacillus coagulans tolerance to 1-ethyl-3-methylimidazolium-based ionic liquids in aqueous and solid-state thermophilic culture journal January 2014
Enrichment, isolation and characterization of fungi tolerant to 1-ethyl-3-methylimidazolium acetate: Ionic liquid-tolerant fungi journal February 2011
Yeast tolerance to the ionic liquid 1-ethyl-3-methylimidazolium acetate journal November 2014
Natural Variation in the Multidrug Efflux Pump SGE1 Underlies Ionic Liquid Tolerance in Yeast journal July 2018
An auto-inducible mechanism for ionic liquid resistance in microbial biofuel production journal March 2014
The Saccharomyces cerevisiae SGE1 gene product: a novel drug-resistance protein within the major facilitator superfamily journal January 1994
Generation of a platform strain for ionic liquid tolerance using adaptive laboratory evolution journal November 2017
Restoration of biofuel production levels and increased tolerance under ionic liquid stress is enabled by a mutation in the essential Escherichia coli gene cydC journal October 2018
Metabolism of Free Guanidine in Bacteria Is Regulated by a Widespread Riboswitch Class journal January 2017
Biochemical Validation of a Second Guanidine Riboswitch Class in Bacteria journal January 2017
Overexpression of the Escherichia coli sugE Gene Confers Resistance to a Narrow Range of Quaternary Ammonium Compounds journal May 2002
Construction of cloning vectors for Bacillus thuringiensis journal December 1991
New RNA motifs suggest an expanded scope for riboswitches in bacterial genetic control journal April 2004
Challenges of ligand identification for riboswitch candidates journal January 2011
Identification of 22 candidate structured RNAs in bacteria using the CMfinder comparative genomics pipeline journal July 2007
Structural basis for guanidine sensing by the ykkC family of riboswitches journal January 2017
Suite of novel vectors for ectopic insertion of GFP, CFP and IYFP transcriptional fusions in single copy at the amyE and bglS loci in Bacillus subtilis journal November 2010
Discovery of two novel β-glucosidases from an Amazon soil metagenomic library journal December 2013
EmrE, an Escherichia coli 12-kDa Multidrug Transporter, Exchanges Toxic Cations and H + and Is Soluble in Organic Solvents journal March 1995
The Structure of the Guanidine-II Riboswitch journal June 2017
Structural basis for ligand binding to the guanidine-II riboswitch journal June 2017
The methyl viologen-resistance-encoding gene smvA of Salmonella typhimurium journal October 1994
Recombinant Bacillus subtilis That Grows on Untreated Plant Biomass journal November 2012
Developing Bacillus spp. as a cell factory for production of microbial enzymes and industrially important biochemicals in the context of systems and synthetic biology journal June 2013
One-step production of biocommodities from lignocellulosic biomass by recombinant cellulolytic Bacillus subtilis: Opportunities and challenges journal August 2010
Small multidrug resistance proteins: A multidrug transporter family that continues to grow journal September 2008
Guanidinium export is the primal function of SMR family transporters journal March 2018
Presence of disinfectant resistance genes in Escherichia coli isolated from retail meats in the USA journal June 2014
Distribution of a transposon-like element carrying blaCMY-2 among Salmonella and other Enterobacteriaceae journal January 2006
CMY-2 β-lactamase-carrying community-acquired urinary tract Escherichia coli: genetic correlation with Salmonella enterica serotypes Choleraesuis and Typhimurium journal April 2007
Glycoside Hydrolase Activities of Thermophilic Bacterial Consortia Adapted to Switchgrass journal July 2011
BglBrick vectors and datasheets: A synthetic biology platform for gene expression journal January 2011
Full expression of the cryIIIA toxin gene of Bacillus thuringiensis requires a distant upstream DNA sequence affecting transcription. journal May 1993
Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants the Keio collection journal February 2006
One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products journal May 2000
Identification and Characterization of a Novel FosA7 Member from Fosfomycin-Resistant Escherichia coli Clinical Isolates from Canadian Hospitals journal December 2020
Restoration of biofuel production levels and increased tolerance under ionic liquid stress is enabled by a mutation in the essential Escherichia coli gene cydC text January 2018

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Improving ionic liquid tolerance in Saccharomyces cerevisiae through heterologous expression and directed evolution of an ILT1 homolog from Yarrowia lipolytica journal August 2019

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