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Grewal J, Khare SK, Drewniak L, Pranaw K. Recent perspectives on microbial and ionic liquid interactions with implications for biorefineries. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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2
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Sørensen PE, Baig S, Stegger M, Ingmer H, Garmyn A, Butaye P. Spontaneous Phage Resistance in Avian Pathogenic Escherichia coli. Front Microbiol 2021; 12:782757. [PMID: 34966369 PMCID: PMC8711792 DOI: 10.3389/fmicb.2021.782757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/23/2021] [Indexed: 01/19/2023] Open
Abstract
Avian pathogenic Escherichia coli (APEC) is one of the most important bacterial pathogens affecting poultry worldwide. The emergence of multidrug-resistant pathogens has renewed the interest in the therapeutic use of bacteriophages (phages). However, a major concern for the successful implementation of phage therapy is the emergence of phage-resistant mutants. The understanding of the phage-host interactions, as well as underlying mechanisms of resistance, have shown to be essential for the development of a successful phage therapy. Here, we demonstrate that the strictly lytic Escherichia phage vB_EcoM-P10 rapidly selected for resistance in the APEC ST95 O1 strain AM621. Whole-genome sequence analysis of 109 spontaneous phage-resistant mutant strains revealed 41 mutants with single-nucleotide polymorphisms (SNPs) in their core genome. In 32 of these, a single SNP was detected while two SNPs were identified in a total of nine strains. In total, 34 unique SNPs were detected. In 42 strains, including 18 strains with SNP(s), gene losses spanning 17 different genes were detected. Affected by genetic changes were genes known to be involved in phage resistance (outer membrane protein A, lipopolysaccharide-, O- antigen-, or cell wall-related genes) as well as genes not previously linked to phage resistance, including two hypothetical genes. In several strains, we did not detect any genetic changes. Infecting phages were not able to overcome the phage resistance in host strains. However, interestingly the initial infection was shown to have a great fitness cost for several mutant strains, with up to ∼65% decrease in overall growth. In conclusion, this study provides valuable insights into the phage-host interaction and phage resistance in APEC. Although acquired resistance to phages is frequently observed in pathogenic E. coli, it may be associated with loss of fitness, which could be exploited in phage therapy.
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Affiliation(s)
- Patricia E. Sørensen
- Department of Pathobiology, Pharmacology and Zoological Medicine, Ghent University, Merelbeke, Belgium
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis
| | - Sharmin Baig
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Marc Stegger
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - An Garmyn
- Department of Pathobiology, Pharmacology and Zoological Medicine, Ghent University, Merelbeke, Belgium
| | - Patrick Butaye
- Department of Pathobiology, Pharmacology and Zoological Medicine, Ghent University, Merelbeke, Belgium
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis
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3
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Liang G, Zhou P, Lu J, Liu H, Qi Y, Gao C, Guo L, Hu G, Chen X, Liu L. Dynamic regulation of membrane integrity to enhance l-malate stress tolerance in Candida glabrata. Biotechnol Bioeng 2021; 118:4347-4359. [PMID: 34302701 DOI: 10.1002/bit.27903] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/29/2021] [Accepted: 07/12/2021] [Indexed: 01/05/2023]
Abstract
Microbial cell factories provide a sustainable and economical way to produce chemicals from renewable feedstocks. However, the accumulation of targeted chemicals can reduce the robustness of the industrial strains and affect the production performance. Here, the physiological functions of Mediator tail subunit CgMed16 at l-malate stress were investigated. Deletion of CgMed16 decreased the survival, biomass, and half-maximal inhibitory concentration (IC50 ) by 40.4%, 34.0%, and 30.6%, respectively, at 25 g/L l-malate stress. Transcriptome analysis showed that this growth defect was attributable to changes in the expression of genes involved in lipid metabolism. In addition, tolerance transcription factors CgUSV1 and CgYAP3 were found to interact with CgMed16 to regulate sterol biosynthesis and glycerophospholipid metabolism, respectively, ultimately endowing strains with excellent membrane integrity to resist l-malate stress. Furthermore, a dynamic tolerance system (DTS) was constructed based on CgUSV1, CgYAP3, and an l-malate-driven promoter Pcgr-10 to improve the robustness and productive capacity of Candida glabrata. As a result, the biomass, survival, and membrane integrity of C. glabrata 012 (with DTS) increased by 22.6%, 31.3%, and 53.8%, respectively, compared with those of strain 011 (without DTS). Therefore, at shake-flask scale, strain 012 accumulated 35.5 g/L l-malate, and the titer and productivity of l-malate increased by 32.5% and 32.1%, respectively, compared with those of strain 011. This study provides a novel strategy for the rational design and construction of DTS for dynamically enhancing the robustness of industrial strains.
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Affiliation(s)
- Guangjie Liang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Pei Zhou
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Jiaxin Lu
- School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Hui Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Yanli Qi
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Liang Guo
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Guipeng Hu
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China.,School of Pharmaceutical Science, Jiangnan University, Wuxi, Jiangsu, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.,School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, China
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4
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Biodegradation of aromatic pollutants meets synthetic biology. Synth Syst Biotechnol 2021; 6:153-162. [PMID: 34278013 PMCID: PMC8260767 DOI: 10.1016/j.synbio.2021.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 05/24/2021] [Accepted: 06/03/2021] [Indexed: 02/02/2023] Open
Abstract
Ubiquitously distributed microorganisms are natural decomposers of environmental pollutants. However, because of continuous generation of novel recalcitrant pollutants due to human activities, it is difficult, if not impossible, for microbes to acquire novel degradation mechanisms through natural evolution. Synthetic biology provides tools to engineer, transform or even re-synthesize an organism purposefully, accelerating transition from unable to able, inefficient to efficient degradation of given pollutants, and therefore, providing new solutions for environmental bioremediation. In this review, we described the pipeline to build chassis cells for the treatment of aromatic pollutants, and presented a proposal to design microbes with emphasis on the strategies applied to modify the target organism at different level. Finally, we discussed challenges and opportunities for future research in this field.
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Horsing around: Escherichia coli ST1250 of equine origin harbouring epidemic IncHI1/ST9 plasmid with bla CTX-M-1 and an operon for short-chain fructooligosaccharides metabolism. Antimicrob Agents Chemother 2021; 65:AAC.02556-20. [PMID: 33619063 PMCID: PMC8092906 DOI: 10.1128/aac.02556-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The relatedness of the equine-associated Escherichia coli ST1250 and its single- and double-locus variants (ST1250-SLV/DLV), obtained from horses in Europe, was studied by comparative genome analysis. A total of 54 isolates of E. coli ST1250 and ST1250-SLV/DLV from healthy and hospitalized horses across Europe [Czech Republic (n=23), the Netherlands (n=18), Germany (n=9), Denmark (n=3) and France (n=1)] from 2008-2017 were subjected to whole-genome sequencing. An additional 25 draft genome assemblies of E. coli ST1250 and ST1250-SLV/DLV were obtained from the public databases. The isolates were compared for genomic features, virulence genes, clade structure and plasmid content. The complete nucleotide sequences of eight IncHI1/ST9 and one IncHI1/ST2 plasmids were obtained using long-read sequencing by PacBio or MinION. In the collection of 79 isolates, only 10 were phylogenetically close (<8 SNP). The majority of isolates belonged to phylogroup B1 (73/79, 92.4%) and carried bla CTX-M-1 (58/79, 73.4%). The plasmid content of the isolates was dominated by IncHI1 of ST9 (56/62, 90.3%) and ST2 (6/62, 9.7%), while 84.5% (49/58) bla CTX-M-1 genes were associated with presence of IncHI1 replicon of ST9 and 6.9% (4/58) with IncHI1 replicon of ST2 within the corresponding isolates. The operon for the utilization of short chain fructooligosaccharides (fos operon) was present in 55 (55/79, 69.6%) isolates, and all of these carried IncHI1/ST9 plasmids. The eight complete IncHI1/ST9 plasmid sequences showed the presence of bla CTX-M-1 and the fos operon within the same molecule. Sequences of IncHI1/ST9 plasmids were highly conserved (>98% similarity) regardless of country of origin and varied only in the structure and integration site of MDR region. E. coli ST1250 and ST1250-SLV/DLV are phylogenetically-diverse strains associated with horses. A strong linkage of E. coli ST1250 with epidemic multi-drug resistance plasmid lineage IncHI1/ST9 carrying bla CTX-M-1 and the fos operon was identified.
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Greene JR, Merrett KL, Heyert AJ, Simmons LF, Migliori CM, Vogt KC, Castro RS, Phillips PD, Baker JL, Lindberg GE, Fox DT, Del Sesto RE, Koppisch AT. Scope and efficacy of the broad-spectrum topical antiseptic choline geranate. PLoS One 2019; 14:e0222211. [PMID: 31527873 PMCID: PMC6748422 DOI: 10.1371/journal.pone.0222211] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/23/2019] [Indexed: 11/18/2022] Open
Abstract
Choline geranate (also described as Choline And GEranic acid, or CAGE) has been developed as a novel biocompatible antiseptic material capable of penetrating skin and aiding the transdermal delivery of co-administered antibiotics. The antibacterial properties of CAGE were analyzed against 24 and 72 hour old biofilms of 11 clinically isolated ESKAPE pathogens (defined as Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter sp, respectively), including multidrug resistant (MDR) isolates. CAGE was observed to eradicate in vitro biofilms at concentrations as low as 3.56 mM (0.156% v:v) in as little as 2 hours, which represents both an improved potency and rate of biofilm eradication relative to that reported for most common standard-of-care topical antiseptics in current use. In vitro time-kill studies on 24 hour old Staphylococcus aureus biofilms indicate that CAGE exerts its antibacterial effect upon contact and a 0.1% v:v solution reduced biofilm viability by over three orders of magnitude (a 3log10 reduction) in 15 minutes. Furthermore, disruption of the protective layer of exopolymeric substances in mature biofilms of Staphylococcus aureus by CAGE (0.1% v:v) was observed in 120 minutes. Insight into the mechanism of action of CAGE was provided with molecular modeling studies alongside in vitro antibiofilm assays. The geranate ion and geranic acid components of CAGE are predicted to act in concert to integrate into bacterial membranes, affect membrane thinning and perturb membrane homeostasis. Taken together, our results show that CAGE demonstrates all properties required of an effective topical antiseptic and the data also provides insight into how its observed antibiofilm properties may manifest.
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Affiliation(s)
- Joshua R. Greene
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Kahla L. Merrett
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Alexanndra J. Heyert
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Lucas F. Simmons
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Camille M. Migliori
- Department of Chemistry, Dixie State University, St. George, UT, United States of America
| | - Kristen C. Vogt
- Department of Chemistry, The College of New Jersey, Ewing, NJ, United States of America
| | - Rebeca S. Castro
- Department of Chemistry, The College of New Jersey, Ewing, NJ, United States of America
| | - Paul D. Phillips
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Joseph L. Baker
- Department of Chemistry, The College of New Jersey, Ewing, NJ, United States of America
| | - Gerrick E. Lindberg
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
- Center for Materials Interfaces in Research and Application, Northern Arizona University, Flagstaff, AZ, United States of America
| | - David T. Fox
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, United States of America
| | - Rico E. Del Sesto
- Department of Chemistry, Dixie State University, St. George, UT, United States of America
| | - Andrew T. Koppisch
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
- Center for Materials Interfaces in Research and Application, Northern Arizona University, Flagstaff, AZ, United States of America
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Eng T, Demling P, Herbert RA, Chen Y, Benites V, Martin J, Lipzen A, Baidoo EEK, Blank LM, Petzold CJ, Mukhopadhyay A. Restoration of biofuel production levels and increased tolerance under ionic liquid stress is enabled by a mutation in the essential Escherichia coli gene cydC. Microb Cell Fact 2018; 17:159. [PMID: 30296937 PMCID: PMC6174563 DOI: 10.1186/s12934-018-1006-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 09/26/2018] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Microbial production of chemicals from renewable carbon sources enables a sustainable route to many bioproducts. Sugar streams, such as those derived from biomass pretreated with ionic liquids (IL), provide efficiently derived and cost-competitive starting materials. A limitation to this approach is that residual ILs in the pretreated sugar source can be inhibitory to microbial growth and impair expression of the desired biosynthetic pathway. RESULTS We utilized laboratory evolution to select Escherichia coli strains capable of robust growth in the presence of the IL, 1-ethyl-3-methyl-imidizolium acetate ([EMIM]OAc). Whole genome sequencing of the evolved strain identified a point mutation in an essential gene, cydC, which confers tolerance to two different classes of ILs at concentrations that are otherwise growth inhibitory. This mutation, cydC-D86G, fully restores the specific production of the bio-jet fuel candidate D-limonene, as well as the biogasoline and platform chemical isopentenol, in growth medium containing ILs. Similar amino acids at this position in cydC, such as cydC-D86V, also confer tolerance to [EMIM]OAc. We show that this [EMIM]OAc tolerance phenotype of cydC-D86G strains is independent of its wild-type function in activating the cytochrome bd-I respiratory complex. Using shotgun proteomics, we characterized the underlying differential cellular responses altered in this mutant. While wild-type E. coli cannot produce detectable amounts of either product in the presence of ILs at levels expected to be residual in sugars from pretreated biomass, the engineered cydC-D86G strains produce over 200 mg/L D-limonene and 350 mg/L isopentenol, which are among the highest reported titers in the presence of [EMIM]OAc. CONCLUSIONS The optimized strains in this study produce high titers of two candidate biofuels and bioproducts under IL stress. Both sets of production strains surpass production titers from other IL tolerant mutants in the literature. Our application of laboratory evolution identified a gain of function mutation in an essential gene, which is unusual in comparison to other published IL tolerant mutants.
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Affiliation(s)
- Thomas Eng
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608 USA
| | - Philipp Demling
- Institute of Applied Microbiology - iAMB, Aachen Biology and Biotechnology - ABBt, RWTH Aachen University, 52074 Aachen, Germany
| | - Robin A. Herbert
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608 USA
| | - Yan Chen
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608 USA
| | - Veronica Benites
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608 USA
| | - Joel Martin
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Walnut Creek, 94598 USA
| | - Anna Lipzen
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Walnut Creek, 94598 USA
| | - Edward E. K. Baidoo
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608 USA
| | - Lars M. Blank
- Institute of Applied Microbiology - iAMB, Aachen Biology and Biotechnology - ABBt, RWTH Aachen University, 52074 Aachen, Germany
| | - Christopher J. Petzold
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608 USA
| | - Aindrila Mukhopadhyay
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608 USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
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8
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Wang S, Sun X, Yuan Q. Strategies for enhancing microbial tolerance to inhibitors for biofuel production: A review. BIORESOURCE TECHNOLOGY 2018; 258:302-309. [PMID: 29567023 DOI: 10.1016/j.biortech.2018.03.064] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/07/2018] [Accepted: 03/09/2018] [Indexed: 05/05/2023]
Abstract
Using lignocellulosic biomass for the production of renewable biofuel provides a sustainable and promising solution to the crisis of energy and environment. However, the processes of biomass pretreatment and biofuel fermentation bring a variety of inhibitors to microbial strains. These inhibitors repress microbial growth, decrease biofuel yields and increase fermentation costs. The production of biofuels from renewable lignocellulosic biomass relies on the development of tolerant and robust microbial strains. In recent years, the advancement of tolerance engineering and evolutionary engineering provides powerful platform for obtaining host strains with desired tolerance for further metabolic engineering of biofuel pathways. In this review, we summarized the inhibitors derived from biomass pretreatment and biofuel fermentation, the mechanisms of inhibitor toxicity, and the strategies for enhancing microbial tolerance.
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Affiliation(s)
- Shizeng Wang
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, PR China
| | - Xinxiao Sun
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, PR China
| | - Qipeng Yuan
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, PR China.
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Egorova KS, Ananikov VP. Ionic liquids in whole-cell biocatalysis: a compromise between toxicity and efficiency. Biophys Rev 2018; 10:881-900. [PMID: 29313188 PMCID: PMC5988618 DOI: 10.1007/s12551-017-0389-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/13/2017] [Indexed: 12/11/2022] Open
Abstract
Comparison of chemical catalysis by metal complexes, enzymatic catalysis and whole-cell biocatalysis shows well-addressed advantages of the latter approach. However, a critical limitation in the practical applications originates from the high sensitivity of microorganisms to the toxic effects of organic solvents. In the present review, we consider toxic solvent properties of ionic liquid/water systems towards the development of efficient applications in practical organic transformations.
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Affiliation(s)
- Ksenia S Egorova
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, Moscow, 119991, Russia
| | - Valentine P Ananikov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, Moscow, 119991, Russia.
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10
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Kluyveromyces marxianus, an Attractive Yeast for Ethanolic Fermentation in the Presence of Imidazolium Ionic Liquids. Int J Mol Sci 2018; 19:ijms19030887. [PMID: 29547579 PMCID: PMC5877748 DOI: 10.3390/ijms19030887] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/11/2018] [Accepted: 03/14/2018] [Indexed: 11/25/2022] Open
Abstract
Imidazolium ionic liquids (ILs) are promising solvents for lignocellulosic biomass (LCB) pretreatment and allow the achievement of higher ethanolic yields after enzymatic hydrolysis and ethanolic fermentation. However, residual ILs entrapped in pretreated biomass are often toxic for fermentative microorganisms, but interaction mechanisms between ILs and cells are still unknown. Here we studied the effects of 1-ethyl-3-methylimidazolium acetate [Emim][OAc] and 1-ethyl-3-methylimidazolium methylphosphonate [Emim][MeO(H)PO2] on Kluyveromyces marxianus, a thermotolerant ethanologenic yeast. Morphological impacts induced by ILs on K. marxianus were characterized by Scanning Electron Microscopy analysis and showed wrinkled, softened, and holed shapes. In Yeast-Malt-Dextrose (YMD) medium, K. marxianus tolerated IL additions up to 2% for [Emim][OAc] and 6% for [Emim][MeO(H)PO2]. Below these thresholds, some IL concentrations enhanced ethanolic yields up to +34% by switching the metabolic status from respiratory to fermentative. Finally, K. marxianus fermentation was applied on several substrates pretreated with [Emim][OAc] or [Emim][MeO(H)PO2] and enzymatically hydrolyzed: a model long fiber cellulose and two industrial LCBs, softwood (spruce) and hardwood (oak) sawdusts. The maximum ethanolic yields obtained were 1.8 to 3.9 times higher when substrates were pretreated with imidazolium ILs. Therefore K. marxianus is an interesting fermentative yeast in a second-generation bioethanol process implying IL pretreatment.
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11
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Dossani ZY, Reider Apel A, Szmidt-Middleton H, Hillson NJ, Deutsch S, Keasling JD, Mukhopadhyay A. A combinatorial approach to synthetic transcription factor-promoter combinations for yeast strain engineering. Yeast 2017; 35:273-280. [PMID: 29084380 PMCID: PMC5873372 DOI: 10.1002/yea.3292] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 09/08/2017] [Accepted: 10/19/2017] [Indexed: 12/28/2022] Open
Abstract
Despite the need for inducible promoters in strain development efforts, the majority of engineering in Saccharomyces cerevisiae continues to rely on a few constitutively active or inducible promoters. Building on advances that use the modular nature of both transcription factors and promoter regions, we have built a library of hybrid promoters that are regulated by a synthetic transcription factor. The hybrid promoters consist of native S. cerevisiae promoters, in which the operator regions have been replaced with sequences that are recognized by the bacterial LexA DNA binding protein. Correspondingly, the synthetic transcription factor (TF) consists of the DNA binding domain of the LexA protein, fused with the human estrogen binding domain and the viral activator domain, VP16. The resulting system with a bacterial DNA binding domain avoids the transcription of native S. cerevisiae genes, and the hybrid promoters can be induced using estradiol, a compound with no detectable impact on S. cerevisiae physiology. Using combinations of one, two or three operator sequence repeats and a set of native S. cerevisiae promoters, we obtained a series of hybrid promoters that can be induced to different levels, using the same synthetic TF and a given estradiol. This set of promoters, in combination with our synthetic TF, has the potential to regulate numerous genes or pathways simultaneously, to multiple desired levels, in a single strain.
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Affiliation(s)
- Zain Y Dossani
- DOE Joint Bioenergy Institute, Emeryville, California, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Amanda Reider Apel
- DOE Joint Bioenergy Institute, Emeryville, California, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Heather Szmidt-Middleton
- DOE Joint Bioenergy Institute, Emeryville, California, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Nathan J Hillson
- DOE Joint Bioenergy Institute, Emeryville, California, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA.,DOE Joint Genome Institute, Walnut Creek, California, USA.,DOE Agile BioFoundry, Emeryville, California, USA
| | - Samuel Deutsch
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA.,DOE Joint Genome Institute, Walnut Creek, California, USA.,DOE Agile BioFoundry, Emeryville, California, USA
| | - Jay D Keasling
- DOE Joint Bioenergy Institute, Emeryville, California, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA.,Department of Chemical and Biomolecular Engineering and Department of Bioengineering, University of California, Berkeley, CA, USA.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220 Kemitorvet, 2800Kgs, Lyngby, Denmark
| | - Aindrila Mukhopadhyay
- DOE Joint Bioenergy Institute, Emeryville, California, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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12
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Mohamed ET, Wang S, Lennen RM, Herrgård MJ, Simmons BA, Singer SW, Feist AM. Generation of a platform strain for ionic liquid tolerance using adaptive laboratory evolution. Microb Cell Fact 2017; 16:204. [PMID: 29145855 PMCID: PMC5691611 DOI: 10.1186/s12934-017-0819-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/09/2017] [Indexed: 11/13/2022] Open
Abstract
Background There is a need to replace petroleum-derived with sustainable feedstocks for chemical production. Certain biomass feedstocks can meet this need as abundant, diverse, and renewable resources. Specific ionic liquids (ILs) can play a role in this process as promising candidates for chemical pretreatment and deconstruction of plant-based biomass feedstocks as they efficiently release carbohydrates which can be fermented. However, the most efficient pretreatment ILs are highly toxic to biological systems, such as microbial fermentations, and hinder subsequent bioprocessing of fermentative sugars obtained from IL-treated biomass. Methods To generate strains capable of tolerating residual ILs present in treated feedstocks, a tolerance adaptive laboratory evolution (TALE) approach was developed and utilized to improve growth of two different Escherichia coli strains, DH1 and K-12 MG1655, in the presence of two different ionic liquids, 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) and 1-butyl-3-methylimidazolium chloride ([C4C1Im]Cl). For multiple parallel replicate populations of E. coli, cells were repeatedly passed to select for improved fitness over the course of approximately 40 days. Clonal isolates were screened and the best performing isolates were subjected to whole genome sequencing. Results The most prevalent mutations in tolerant clones occurred in transport processes related to the functions of mdtJI, a multidrug efflux pump, and yhdP, an uncharacterized transporter. Additional mutations were enriched in processes such as transcriptional regulation and nucleotide biosynthesis. Finally, the best-performing strains were compared to previously characterized tolerant strains and showed superior performance in tolerance of different IL and media combinations (i.e., cross tolerance) with robust growth at 8.5% (w/v) and detectable growth up to 11.9% (w/v) [C2C1Im][OAc]. Conclusion The generated strains thus represent the best performing platform strains available for bioproduction utilizing IL-treated renewable substrates, and the TALE method was highly successful in overcoming the general issue of substrate toxicity and has great promise for use in tolerance engineering. Electronic supplementary material The online version of this article (10.1186/s12934-017-0819-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elsayed T Mohamed
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800, Kgs. Lyngby, Denmark
| | - Shizeng Wang
- Joint Bioenergy Institute, Emeryville, CA, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China
| | - Rebecca M Lennen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800, Kgs. Lyngby, Denmark
| | - Markus J Herrgård
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800, Kgs. Lyngby, Denmark
| | - Blake A Simmons
- Joint Bioenergy Institute, Emeryville, CA, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Steven W Singer
- Joint Bioenergy Institute, Emeryville, CA, USA.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Adam M Feist
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800, Kgs. Lyngby, Denmark. .,Department of Bioengineering, University of California, 9500 Gilman Drive La Jolla, San Diego, CA, 92093, USA.
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13
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Egorova KS, Gordeev EG, Ananikov VP. Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine. Chem Rev 2017; 117:7132-7189. [PMID: 28125212 DOI: 10.1021/acs.chemrev.6b00562] [Citation(s) in RCA: 911] [Impact Index Per Article: 130.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in the form of ionic liquid species. The main aim of this Review is to attract a broad audience of chemical, biological, and medical scientists to study advantages of ionic liquid pharmaceutics. Overall, the discussed data highlight the importance of the research direction defined as "Ioliomics", studies of ions in liquids in modern chemistry, biology, and medicine.
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Affiliation(s)
- Ksenia S Egorova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , Leninsky prospect 47, Moscow 119991, Russia
| | - Evgeniy G Gordeev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , Leninsky prospect 47, Moscow 119991, Russia
| | - Valentine P Ananikov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , Leninsky prospect 47, Moscow 119991, Russia.,Department of Chemistry, Saint Petersburg State University , Stary Petergof 198504, Russia
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14
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Seppälä S, Solomon KV, Gilmore SP, Henske JK, O'Malley MA. Mapping the membrane proteome of anaerobic gut fungi identifies a wealth of carbohydrate binding proteins and transporters. Microb Cell Fact 2016; 15:212. [PMID: 27998268 PMCID: PMC5168858 DOI: 10.1186/s12934-016-0611-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 12/02/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Engineered cell factories that convert biomass into value-added compounds are emerging as a timely alternative to petroleum-based industries. Although often overlooked, integral membrane proteins such as solute transporters are pivotal for engineering efficient microbial chassis. Anaerobic gut fungi, adapted to degrade raw plant biomass in the intestines of herbivores, are a potential source of valuable transporters for biotechnology, yet very little is known about the membrane constituents of these non-conventional organisms. Here, we mined the transcriptome of three recently isolated strains of anaerobic fungi to identify membrane proteins responsible for sensing and transporting biomass hydrolysates within a competitive and rather extreme environment. RESULTS Using sequence analyses and homology, we identified membrane protein-coding sequences from assembled transcriptomes from three strains of anaerobic gut fungi: Neocallimastix californiae, Anaeromyces robustus, and Piromyces finnis. We identified nearly 2000 transporter components: about half of these are involved in the general secretory pathway and intracellular sorting of proteins; the rest are predicted to be small-solute transporters. Unexpectedly, we found a number of putative sugar binding proteins that are associated with prokaryotic uptake systems; and approximately 100 class C G-protein coupled receptors (GPCRs) with non-canonical putative sugar binding domains. CONCLUSIONS We report the first comprehensive characterization of the membrane protein machinery of biotechnologically relevant anaerobic gut fungi. Apart from identifying conserved machinery for protein sorting and secretion, we identify a large number of putative solute transporters that are of interest for biotechnological applications. Notably, our data suggests that the fungi display a plethora of carbohydrate binding domains at their surface, perhaps as a means to sense and sequester some of the sugars that their biomass degrading, extracellular enzymes produce.
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Affiliation(s)
- Susanna Seppälä
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet Bygning 220, 2800, Kgs. Lyngby, Denmark.,Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Kevin V Solomon
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA.,Agricultural and Biological Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Sean P Gilmore
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - John K Henske
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA
| | - Michelle A O'Malley
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA.
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15
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Yu C, Simmons BA, Singer SW, Thelen MP, VanderGheynst JS. Ionic liquid-tolerant microorganisms and microbial communities for lignocellulose conversion to bioproducts. Appl Microbiol Biotechnol 2016; 100:10237-10249. [PMID: 27838839 DOI: 10.1007/s00253-016-7955-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 10/19/2016] [Accepted: 10/21/2016] [Indexed: 11/26/2022]
Abstract
Chemical and physical pretreatment of biomass is a critical step in the conversion of lignocellulose to biofuels and bioproducts. Ionic liquid (IL) pretreatment has attracted significant attention due to the unique ability of certain ILs to solubilize some or all components of the plant cell wall. However, these ILs inhibit not only the enzyme activities but also the growth and productivity of microorganisms used in downstream hydrolysis and fermentation processes. While pretreated biomass can be washed to remove residual IL and reduce inhibition, extensive washing is costly and not feasible in large-scale processes. IL-tolerant microorganisms and microbial communities have been discovered from environmental samples and studies begun to elucidate mechanisms of IL tolerance. The discovery of IL tolerance in environmental microbial communities and individual microbes has lead to the proposal of molecular mechanisms of resistance. In this article, we review recent progress on discovering IL-tolerant microorganisms, identifying metabolic pathways and mechanisms of tolerance, and engineering microorganisms for IL tolerance. Research in these areas will yield new approaches to overcome inhibition in lignocellulosic biomass bioconversion processes and increase opportunities for the use of ILs in biomass pretreatment.
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Affiliation(s)
- Chaowei Yu
- Department of Biological and Agricultural Engineering, University of California, One Shields Ave., Davis, CA, 95616, USA
| | - Blake A Simmons
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Steven W Singer
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Michael P Thelen
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Biosciences Division, Lawrence Livermore National Laboratory, Livermore, CA, 94551, USA
| | - Jean S VanderGheynst
- Department of Biological and Agricultural Engineering, University of California, One Shields Ave., Davis, CA, 95616, USA.
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.
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16
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Gupta VK, Kubicek CP, Berrin JG, Wilson DW, Couturier M, Berlin A, Filho EXF, Ezeji T. Fungal Enzymes for Bio-Products from Sustainable and Waste Biomass. Trends Biochem Sci 2016; 41:633-645. [PMID: 27211037 DOI: 10.1016/j.tibs.2016.04.006] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 04/13/2016] [Accepted: 04/22/2016] [Indexed: 12/19/2022]
Abstract
Lignocellulose, the most abundant renewable carbon source on earth, is the logical candidate to replace fossil carbon as the major biofuel raw material. Nevertheless, the technologies needed to convert lignocellulose into soluble products that can then be utilized by the chemical or fuel industries face several challenges. Enzymatic hydrolysis is of major importance, and we review the progress made in fungal enzyme technology over the past few years with major emphasis on (i) the enzymes needed for the conversion of polysaccharides (cellulose and hemicellulose) into soluble products, (ii) the potential uses of lignin degradation products, and (iii) current progress and bottlenecks for the use of the soluble lignocellulose derivatives in emerging biorefineries.
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Affiliation(s)
- Vijai K Gupta
- Molecular Glycobiotechnology Group, Discipline of Biochemistry, National University of Ireland Galway, Galway City, Ireland.
| | - Christian P Kubicek
- Biotechnology and Microbiology, Institute of Chemical Engineering, Technische Universität Wien, Gumpendorferstrasse, 1060 Wien, Austria
| | - Jean-Guy Berrin
- Institut National de la Recherche Agronomique (INRA), Unité Mixte de Recherche (UMR) 1163-Biodiversité et Biotechnologie Fongiques, Avenue de Luminy, 13288 Marseille, France; Aix Marseille Université, UMR1163 Biodiversité et Biotechnologie Fongiques, Avenue de Luminy, 13288 Marseille, France
| | - David W Wilson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Marie Couturier
- Institut National de la Recherche Agronomique (INRA), Unité Mixte de Recherche (UMR) 1163-Biodiversité et Biotechnologie Fongiques, Avenue de Luminy, 13288 Marseille, France; Aix Marseille Université, UMR1163 Biodiversité et Biotechnologie Fongiques, Avenue de Luminy, 13288 Marseille, France
| | - Alex Berlin
- Novozymes, Inc., 1445 Drew Ave, Davis CA 95618 USA
| | - Edivaldo X F Filho
- Laboratory of Enzymology, Department of Cell Biology, University of Brasilia, Asa Norte, 70910-900 Brasilia, DF Brazil
| | - Thaddeus Ezeji
- Biotechnology and Fermentation Group, Department of Animal Sciences, Ohio State University and Ohio Agricultural Research and Development Center (OARDC), Madison Avenue, Wooster, OH 44691, USA
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17
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Bandiera L, Furini S, Giordano E. Phenotypic Variability in Synthetic Biology Applications: Dealing with Noise in Microbial Gene Expression. Front Microbiol 2016; 7:479. [PMID: 27092132 PMCID: PMC4824758 DOI: 10.3389/fmicb.2016.00479] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/22/2016] [Indexed: 01/08/2023] Open
Abstract
The stochasticity due to the infrequent collisions among low copy-number molecules within the crowded cellular compartment is a feature of living systems. Single cell variability in gene expression within an isogenic population (i.e., biological noise) is usually described as the sum of two independent components: intrinsic and extrinsic stochasticity. Intrinsic stochasticity arises from the random occurrence of events inherent to the gene expression process (e.g., the burst-like synthesis of mRNA and protein molecules). Extrinsic fluctuations reflect the state of the biological system and its interaction with the intra and extracellular environments (e.g., concentration of available polymerases, ribosomes, metabolites, and micro-environmental conditions). A better understanding of cellular noise would help synthetic biologists design gene circuits with well-defined functional properties. In silico modeling has already revealed several aspects of the network topology’s impact on noise properties; this information could drive the selection of biological parts and the design of reliably engineered pathways. Importantly, while optimizing artificial gene circuitry for industrial applications, synthetic biology could also elucidate the natural mechanisms underlying natural phenotypic variability. In this review, we briefly summarize the functional roles of noise in unicellular organisms and address their relevance to synthetic network design. We will also consider how noise might influence the selection of network topologies supporting reliable functions, and how the variability of cellular events might be exploited when designing innovative biotechnology applications.
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Affiliation(s)
- Lucia Bandiera
- Laboratory of Cellular and Molecular Engineering "S. Cavalcanti", Department of Electrical, Electronic and Information Engineering "G. Marconi", University of Bologna Cesena, Italy
| | - Simone Furini
- Department of Medical Biotechnologies, University of Siena Siena, Italy
| | - Emanuele Giordano
- Laboratory of Cellular and Molecular Engineering "S. Cavalcanti", Department of Electrical, Electronic and Information Engineering "G. Marconi", University of BolognaCesena, Italy; BioEngLab, Health Science and Technology, Interdepartmental Center for Industrial Research, University of BolognaCesena, Italy; Advanced Research Center on Electronic Systems, University of BolognaCesena, Italy
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18
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Chubukov V, Mukhopadhyay A, Petzold CJ, Keasling JD, Martín HG. Synthetic and systems biology for microbial production of commodity chemicals. NPJ Syst Biol Appl 2016; 2:16009. [PMID: 28725470 PMCID: PMC5516863 DOI: 10.1038/npjsba.2016.9] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/01/2016] [Accepted: 02/05/2016] [Indexed: 01/08/2023] Open
Abstract
The combination of synthetic and systems biology is a powerful framework to study fundamental questions in biology and produce chemicals of immediate practical application such as biofuels, polymers, or therapeutics. However, we cannot yet engineer biological systems as easily and precisely as we engineer physical systems. In this review, we describe the path from the choice of target molecule to scaling production up to commercial volumes. We present and explain some of the current challenges and gaps in our knowledge that must be overcome in order to bring our bioengineering capabilities to the level of other engineering disciplines. Challenges start at molecule selection, where a difficult balance between economic potential and biological feasibility must be struck. Pathway design and construction have recently been revolutionized by next-generation sequencing and exponentially improving DNA synthesis capabilities. Although pathway optimization can be significantly aided by enzyme expression characterization through proteomics, choosing optimal relative protein expression levels for maximum production is still the subject of heuristic, non-systematic approaches. Toxic metabolic intermediates and proteins can significantly affect production, and dynamic pathway regulation emerges as a powerful but yet immature tool to prevent it. Host engineering arises as a much needed complement to pathway engineering for high bioproduct yields; and systems biology approaches such as stoichiometric modeling or growth coupling strategies are required. A final, and often underestimated, challenge is the successful scale up of processes to commercial volumes. Sustained efforts in improving reproducibility and predictability are needed for further development of bioengineering.
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Affiliation(s)
- Victor Chubukov
- Joint BioEnergy Institute, Emeryville, CA, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Aindrila Mukhopadhyay
- Joint BioEnergy Institute, Emeryville, CA, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Christopher J Petzold
- Joint BioEnergy Institute, Emeryville, CA, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jay D Keasling
- Joint BioEnergy Institute, Emeryville, CA, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Chemical & Biomolecular Engineering, University of California, Berkeley, CA, USA
- Department of Bioengineering, University of California, Berkeley, CA, USA
| | - Héctor García Martín
- Joint BioEnergy Institute, Emeryville, CA, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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19
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Lindle JM, Dunlop MJ. Performing selections under dynamic conditions for synthetic biology applications. Integr Biol (Camb) 2016; 8:556-63. [PMID: 26758547 DOI: 10.1039/c5ib00286a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
As the design of synthetic circuits and metabolic networks becomes more complex it is often difficult to know a priori which parameters and design choices will result in a desired phenotype. To counter this, rational design can be complemented by library-based approaches where diversity is introduced and then coupled with screening or selection methods. Here, we used a model of competitive growth to show that selection can rapidly identify library variants with near-optimal phenotypes. Many synthetic biology applications require phenotypes that balance multiple objectives, such as responding to more than one chemical signal. In addition, desired traits may be time-dependent, for example changing with the growth phase. By applying dynamic inputs to the selection, we show that it is possible to select for traits that satisfy multiple goals. Furthermore, we demonstrate that the underlying diversity in a library is heavily influenced by the initial circuit design. Overall, our findings argue that rational synthetic circuit design, coupled with diversity generation and dynamic selection are powerful tools for many synthetic biology applications.
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Affiliation(s)
- Jessica M Lindle
- School of Engineering, University of Vermont, Burlington, VT 05405, USA.
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20
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Ghanem OB, Mutalib MIA, El-Harbawi M, Gonfa G, Kait CF, Alitheen NBM, Leveque JM. Effect of imidazolium-based ionic liquids on bacterial growth inhibition investigated via experimental and QSAR modelling studies. JOURNAL OF HAZARDOUS MATERIALS 2015; 297:198-206. [PMID: 25965417 DOI: 10.1016/j.jhazmat.2015.04.082] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 06/04/2023]
Abstract
Tuning the characteristics of solvents to fit industrial requirements has currently become a major interest in both academic and industrial communities, notably in the field of room temperature ionic liquids (RTILs), which are considered one of the most promising green alternatives to molecular organic solvents. In this work, several sets of imidazolium-based ionic liquids were synthesized, and their toxicities were assessed towards four human pathogens bacteria to investigate how tunability can affect this characteristic. Additionally, the toxicity of particular RTILs bearing an amino acid anion was introduced in this work. EC50 values (50% effective concentration) were established, and significant variations were observed; although all studied ILs displayed an imidazolium moiety, the toxicity values were found to vary between 0.05 mM for the most toxic to 85.57 mM for the least toxic. Linear quantitative structure activity relationship models were then developed using the charge density distribution (σ-profiles) as molecular descriptors, which can yield accuracies as high as 95%.
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Affiliation(s)
- Ouahid Ben Ghanem
- Faculty of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia.
| | - M I Abdul Mutalib
- Faculty of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia
| | - Mohanad El-Harbawi
- Chemical Engineering Department, King Saud University, Riyadh 11421, Saudi Arabia
| | - Girma Gonfa
- Faculty of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia
| | - Chong Fai Kait
- Fundamental & Applied Sciences Department, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Tronoh, Perak, Malaysia
| | - Noorjahan Banu Mohamed Alitheen
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Jean-Marc Leveque
- Fundamental & Applied Sciences Department, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Tronoh, Perak, Malaysia.
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21
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Turner WJ, Dunlop MJ. Trade-Offs in Improving Biofuel Tolerance Using Combinations of Efflux Pumps. ACS Synth Biol 2015; 4:1056-63. [PMID: 25496359 DOI: 10.1021/sb500307w] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Microbes can be engineered to produce next-generation biofuels; however, the accumulation of toxic biofuels can limit yields. Previous studies have shown that efflux pumps can increase biofuel tolerance and improve production. Here, we asked whether expressing multiple pumps in combination could further increase biofuel tolerance. Pump overexpression inhibits cell growth, suggesting a trade-off between biofuel and pump toxicity. With multiple pumps, it is unclear how the fitness landscape is impacted. To address this, we measured tolerance of Escherichia coli to the biojet fuel precursor α-pinene in one-pump and two-pump strains. To support our experiments, we developed a mathematical model describing toxicity due to biofuel and overexpression of pumps. We found that data from one-pump strains can accurately predict the performance of two-pump strains. This result suggests that it may be possible to dramatically reduce the number of experiments required for characterizing the effects of combined biofuel tolerance mechanisms.
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Affiliation(s)
- William J. Turner
- School
of Engineering, University of Vermont, Burlington, Vermont 05405, United States
| | - Mary J. Dunlop
- School
of Engineering, University of Vermont, Burlington, Vermont 05405, United States
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22
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Biofuels and bio-based chemicals from lignocellulose: metabolic engineering strategies in strain development. Biotechnol Lett 2015; 38:213-21. [PMID: 26466596 DOI: 10.1007/s10529-015-1976-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/07/2015] [Indexed: 12/22/2022]
Abstract
Interest in developing a sustainable technology for fuels and chemicals has unleashed tremendous creativity in metabolic engineering for strain development over the last few years. This is driven by the exceptionally recalcitrant substrate, lignocellulose, and the necessity to keep the costs down for commodity products. Traditional methods of gene expression and evolutionary engineering are more effectively used with the help of synthetic biology and -omics techniques. Compared to the last biomass research peak during the 1980s oil crisis, a more diverse range of microorganisms are being engineered for a greater variety of products, reflecting the broad applicability and effectiveness of today's gene technology. We review here several prominent and successful metabolic engineering strategies with emphasis on the following four areas: xylose catabolism, inhibitor tolerance, synthetic microbial consortium, and cellulosic oligomer assimilation.
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23
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Petzold CJ, Chan LJG, Nhan M, Adams PD. Analytics for Metabolic Engineering. Front Bioeng Biotechnol 2015; 3:135. [PMID: 26442249 PMCID: PMC4561385 DOI: 10.3389/fbioe.2015.00135] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 08/24/2015] [Indexed: 12/20/2022] Open
Abstract
Realizing the promise of metabolic engineering has been slowed by challenges related to moving beyond proof-of-concept examples to robust and economically viable systems. Key to advancing metabolic engineering beyond trial-and-error research is access to parts with well-defined performance metrics that can be readily applied in vastly different contexts with predictable effects. As the field now stands, research depends greatly on analytical tools that assay target molecules, transcripts, proteins, and metabolites across different hosts and pathways. Screening technologies yield specific information for many thousands of strain variants, while deep omics analysis provides a systems-level view of the cell factory. Efforts focused on a combination of these analyses yield quantitative information of dynamic processes between parts and the host chassis that drive the next engineering steps. Overall, the data generated from these types of assays aid better decision-making at the design and strain construction stages to speed progress in metabolic engineering research.
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Affiliation(s)
- Christopher J Petzold
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National Laboratory , Berkeley, CA , USA
| | - Leanne Jade G Chan
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National Laboratory , Berkeley, CA , USA
| | - Melissa Nhan
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National Laboratory , Berkeley, CA , USA
| | - Paul D Adams
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National Laboratory , Berkeley, CA , USA ; Department of Bioengineering, University of California Berkeley , Berkeley, CA , USA
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24
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Mukhopadhyay A. Tolerance engineering in bacteria for the production of advanced biofuels and chemicals. Trends Microbiol 2015; 23:498-508. [DOI: 10.1016/j.tim.2015.04.008] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/17/2015] [Accepted: 04/23/2015] [Indexed: 02/06/2023]
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25
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Mingardon F, Clement C, Hirano K, Nhan M, Luning EG, Chanal A, Mukhopadhyay A. Improving olefin tolerance and production in E. coli using native and evolved AcrB. Biotechnol Bioeng 2015; 112:879-88. [PMID: 25450012 PMCID: PMC4406151 DOI: 10.1002/bit.25511] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 11/16/2014] [Accepted: 11/25/2014] [Indexed: 01/10/2023]
Abstract
Microorganisms can be engineered for the production of chemicals utilized in the polymer industry. However many such target compounds inhibit microbial growth and might correspondingly limit production levels. Here, we focus on compounds that are precursors to bioplastics, specifically styrene and representative alpha-olefins; 1-hexene, 1-octene, and 1-nonene. We evaluated the role of the Escherichia coli efflux pump, AcrAB-TolC, in enhancing tolerance towards these olefin compounds. AcrAB-TolC is involved in the tolerance towards all four compounds in E. coli. Both styrene and 1-hexene are highly toxic to E. coli. Styrene is a model plastics precursor with an established route for production in E. coli (McKenna and Nielsen, 2011). Though our data indicates that AcrAB-TolC is important for its optimal production, we observed a strong negative selection against the production of styrene in E. coli. Thus we used 1-hexene as a model compound to implement a directed evolution strategy to further improve the tolerance phenotype towards this alpha-olefin. We focused on optimization of AcrB, the inner membrane domain known to be responsible for substrate binding, and found several mutations (A279T, Q584R, F617L, L822P, F927S, and F1033Y) that resulted in improved tolerance. Several of these mutations could also be combined in a synergistic manner. Our study shows efflux pumps to be an important mechanism in host engineering for olefins, and one that can be further improved using strategies such as directed evolution, to increase tolerance and potentially production. Biotechnol. Bioeng. 2015;112: 879–888. © 2015 The Authors. Biotechnology and Bioengineering Published by John Wiley & Periodicals, Inc.
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