1
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Mika T, Kalnins M, Spalvins K. The use of droplet-based microfluidic technologies for accelerated selection of Yarrowia lipolytica and Phaffia rhodozyma yeast mutants. Biol Methods Protoc 2024; 9:bpae049. [PMID: 39114747 PMCID: PMC11303513 DOI: 10.1093/biomethods/bpae049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Revised: 06/24/2024] [Accepted: 07/09/2024] [Indexed: 08/10/2024] Open
Abstract
Microorganisms are widely used for the industrial production of various valuable products, such as pharmaceuticals, food and beverages, biofuels, enzymes, amino acids, vaccines, etc. Research is constantly carried out to improve their properties, mainly to increase their productivity and efficiency and reduce the cost of the processes. The selection of microorganisms with improved qualities takes a lot of time and resources (both human and material); therefore, this process itself needs optimization. In the last two decades, microfluidics technology appeared in bioengineering, which allows for manipulating small particles (from tens of microns to nanometre scale) in the flow of liquid in microchannels. The technology is based on small-volume objects (microdroplets from nano to femtolitres), which are manipulated using a microchip. The chip is made of an optically transparent inert to liquid medium material and contains a series of channels of small size (<1 mm) of certain geometry. Based on the physical and chemical properties of microparticles (like size, weight, optical density, dielectric constant, etc.), they are separated using microsensors. The idea of accelerated selection of microorganisms is the application of microfluidic technologies to separate mutants with improved qualities after mutagenesis. This article discusses the possible application and practical implementation of microfluidic separation of mutants, including yeasts like Yarrowia lipolytica and Phaffia rhodozyma after chemical mutagenesis will be discussed.
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Affiliation(s)
- Taras Mika
- Institute of Energy Systems and Environment, Riga Technical University, 12 – K1 Āzene street, Riga, LV-1048, Latvia
| | - Martins Kalnins
- Institute of Energy Systems and Environment, Riga Technical University, 12 – K1 Āzene street, Riga, LV-1048, Latvia
| | - Kriss Spalvins
- Institute of Energy Systems and Environment, Riga Technical University, 12 – K1 Āzene street, Riga, LV-1048, Latvia
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2
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Gan L, Huang X, He Z, He T. Exopolysaccharide production by salt-tolerant bacteria: Recent advances, current challenges, and future prospects. Int J Biol Macromol 2024; 264:130731. [PMID: 38471615 DOI: 10.1016/j.ijbiomac.2024.130731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/27/2024] [Accepted: 03/06/2024] [Indexed: 03/14/2024]
Abstract
Natural biopolymers derived from exopolysaccharides (EPSs) are considered eco-friendly and sustainable alternatives to available traditional synthetic counterparts. Salt-tolerant bacteria inhabiting harsh ecological niches have evolved a number of unique adaptation strategies allowing them to maintain cellular integrity and assuring their long-term survival; among these, producing EPSs can be adopted as an effective strategy to thrive under high-salt conditions. A great diversity of EPSs from salt-tolerant bacteria have attracted widespread attention recently. Because of factors such as their unique structural, physicochemical, and functional characteristics, EPSs are commercially valuable for the global market and their application potential in various sectors is promising. However, large-scale production and industrial development of these biopolymers are hindered by their low yields and high costs. Consequently, the research progress and future prospects of salt-tolerant bacterial EPSs must be systematically reviewed to further promote their application and commercialization. In this review, the structure and properties of EPSs produced by a variety of salt-tolerant bacterial strains isolated from different sources are summarized. Further, feasible strategies for solving production bottlenecks are discussed, which provides a scientific basis and direct reference for more scientific and rational EPS development.
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Affiliation(s)
- Longzhan Gan
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences, Guizhou University, Guiyang 550025, Guizhou Province, China.
| | - Xin Huang
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences, Guizhou University, Guiyang 550025, Guizhou Province, China
| | - Zhicheng He
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences, Guizhou University, Guiyang 550025, Guizhou Province, China
| | - Tengxia He
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences, Guizhou University, Guiyang 550025, Guizhou Province, China.
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3
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Pourmasoumi F, Hengoju S, Beck K, Stephan P, Klopfleisch L, Hoernke M, Rosenbaum MA, Kries H. Analysing Megasynthetase Mutants at High Throughput Using Droplet Microfluidics. Chembiochem 2023; 24:e202300680. [PMID: 37804133 DOI: 10.1002/cbic.202300680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 10/05/2023] [Indexed: 10/08/2023]
Abstract
Nonribosomal peptide synthetases (NRPSs) are giant enzymatic assembly lines that deliver many pharmaceutically valuable natural products, including antibiotics. As the search for new antibiotics motivates attempts to redesign nonribosomal metabolic pathways, more robust and rapid sorting and screening platforms are needed. Here, we establish a microfluidic platform that reliably detects production of the model nonribosomal peptide gramicidin S. The detection is based on calcein-filled sensor liposomes yielding increased fluorescence upon permeabilization. From a library of NRPS mutants, the sorting platform enriches the gramicidin S producer 14.5-fold, decreases internal stop codons 250-fold, and generates enrichment factors correlating with enzyme activity. Screening for NRPS activity with a reliable non-binary sensor will enable more sophisticated structure-activity studies and new engineering applications in the future.
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Affiliation(s)
- Farzaneh Pourmasoumi
- Junior Research Group Biosynthetic Design of Natural Products, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Sundar Hengoju
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Katharina Beck
- Faculty of Chemistry and Pharmacy, Albert-Ludwigs-Universität, Hermann-Herder-Str. 9, 79104, Freiburg i. Br., Germany
| | - Philipp Stephan
- Junior Research Group Biosynthetic Design of Natural Products, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Lukas Klopfleisch
- Junior Research Group Biosynthetic Design of Natural Products, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
| | - Maria Hoernke
- Faculty of Chemistry and Pharmacy, Albert-Ludwigs-Universität, Hermann-Herder-Str. 9, 79104, Freiburg i. Br., Germany
- Faculty of Chemistry, Martin-Luther-Universität, Von-Danckelmann-Platz 4, 06108, Halle (S.), Germany
| | - Miriam A Rosenbaum
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
- Faculty of Biological Sciences, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Hajo Kries
- Junior Research Group Biosynthetic Design of Natural Products, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745, Jena, Germany
- Department of Chemistry, University of Bayreuth, Universitätsstrasse 30, 95440, Bayreuth, Germany
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4
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Osgerby A, Overton TW. Approaches for high-throughput quantification of periplasmic recombinant proteins. N Biotechnol 2023; 77:149-160. [PMID: 37708933 DOI: 10.1016/j.nbt.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 09/01/2023] [Accepted: 09/11/2023] [Indexed: 09/16/2023]
Abstract
The Gram-negative periplasm is a convenient location for the accumulation of many recombinant proteins including biopharmaceutical products. It is the site of disulphide bond formation, required by some proteins (such as antibody fragments) for correct folding and function. It also permits simpler protein release and downstream processing than cytoplasmic accumulation. As such, targeting of recombinant proteins to the E. coli periplasm is a key strategy in biologic manufacture. However, expression and translocation of each recombinant protein requires optimisation including selection of the best signal peptide and growth and production conditions. Traditional methods require separation and analysis of protein compositions of periplasmic and cytoplasmic fractions, a time- and labour-intensive method that is difficult to parallelise. Therefore, approaches for high throughput quantification of periplasmic protein accumulation offer advantages in rapid process development.
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Affiliation(s)
- Alexander Osgerby
- School of Chemical Engineering and Institute of Microbiology and Infection, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Tim W Overton
- School of Chemical Engineering and Institute of Microbiology and Infection, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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5
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Wei X, Chen Z, Liu A, Yang L, Xu Y, Cao M, He N. Advanced strategies for metabolic engineering of Bacillus to produce extracellular polymeric substances. Biotechnol Adv 2023; 67:108199. [PMID: 37330153 DOI: 10.1016/j.biotechadv.2023.108199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 05/24/2023] [Accepted: 06/11/2023] [Indexed: 06/19/2023]
Abstract
Extracellular polymeric substances are mainly synthesized via a variety of biosynthetic pathways in bacteria. Bacilli-sourced extracellular polymeric substances, such as exopolysaccharides (EPS) and poly-γ-glutamic acid (γ-PGA), can serve as active ingredients and hydrogels, and have other important industrial applications. However, the functional diversity and widespread applications of these extracellular polymeric substances, are hampered by their low yields and high costs. Biosynthesis of extracellular polymeric substances is very complex in Bacillus, and there is no detailed elucidation of the reactions and regulations among various metabolic pathways. Therefore, a better understanding of the metabolic mechanisms is required to broaden the functions and increase the yield of extracellular polymeric substances. This review systematically summarizes the biosynthesis and metabolic mechanisms of extracellular polymeric substances in Bacillus, providing an in-depth understanding of the relationships between EPS and γ-PGA synthesis. This review provides a better clarification of Bacillus metabolic mechanisms during extracellular polymeric substance secretion and thus benefits their application and commercialization.
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Affiliation(s)
- Xiaoyu Wei
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Zhen Chen
- College of Life Science, Xinyang Normal University, Xinyang 464000, China.
| | - Ailing Liu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Lijie Yang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Yiyuan Xu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China; Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen 361005, China.
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China.
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6
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Song X, Kong SJ, Seo S, Prabhakar RG, Shamoo Y. Methyl halide transferase-based gas reporters for quantification of filamentous bacteria in microdroplet emulsions. Appl Environ Microbiol 2023; 89:e0076423. [PMID: 37699129 PMCID: PMC10537575 DOI: 10.1128/aem.00764-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/19/2023] [Indexed: 09/14/2023] Open
Abstract
The application of microfluidic techniques in experimental and environmental studies is a rapidly emerging field. Water-in-oil microdroplets can serve readily as controllable micro-vessels for studies that require spatial structure. In many applications, it is useful to monitor cell growth without breaking or disrupting the microdroplets. To this end, optical reporters based on color, fluorescence, or luminescence have been developed. However, optical reporters suffer from limitations when used in microdroplets such as inaccurate readings due to strong background interference or limited sensitivity during early growth stages. In addition, optical detection is typically not amenable to filamentous or biofilm-producing organisms that have significant nonlinear changes in opacity and light scattering during growth. To overcome such limitations, we show that volatile methyl halide gases produced by reporter cells expressing a methyl halide transferase (MHT) can serve as an alternative nonoptical detection approach suitable for microdroplets. In this study, an MHT-labeled Streptomyces venezuelae reporter strain was constructed and characterized. Protocols were established for the encapsulation and incubation of S. venezuelae in microdroplets. We observed the complete life cycle for S. venezuelae including the vegetative expansion of mycelia, mycelial fragmentation, and late-stage sporulation. Methyl bromide (MeBr) production was detected by gas chromatography-mass spectrometry (GC-MS) from S. venezuelae gas reporters incubated in either liquid suspension or microdroplets and used to quantitatively estimate bacterial density. Overall, using MeBr production as a means of quantifying bacterial growth provided a 100- to 1,000-fold increase in sensitivity over optical or fluorescence measurements of a comparable reporter strain expressing fluorescent proteins. IMPORTANCE Quantitative measurement of bacterial growth in microdroplets in situ is desirable but challenging. Current optical reporter systems suffer from limitations when applied to filamentous or biofilm-producing organisms. In this study, we demonstrate that volatile methyl halide gas production can serve as a quantitative nonoptical growth assay for filamentous bacteria encapsulated in microdroplets. We constructed an S. venezuelae gas reporter strain and observed a complete life cycle for encapsulated S. venezuelae in microdroplets, establishing microdroplets as an alternative growth environment for Streptomyces spp. that can provide spatial structure. We detected MeBr production from both liquid suspension and microdroplets with a 100- to 1,000-fold increase in signal-to-noise ratio compared to optical assays. Importantly, we could reliably detect bacteria with densities down to 106 CFU/mL. The combination of quantitative gas reporting and microdroplet systems provides a valuable approach to studying fastidious organisms that require spatial structure such as those found typically in soils.
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Affiliation(s)
- Xinhao Song
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Sarah J. Kong
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Seokju Seo
- Department of BioSciences, Rice University, Houston, Texas, USA
| | | | - Yousif Shamoo
- Department of BioSciences, Rice University, Houston, Texas, USA
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7
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Prabhakar RG, Fan G, Alnahhas RN, Hirning AJ, Bennett MR, Shamoo Y. Indirect Enrichment of Desirable, but Less Fit Phenotypes, from a Synthetic Microbial Community Using Microdroplet Confinement. ACS Synth Biol 2023; 12:1239-1251. [PMID: 36929925 PMCID: PMC11259032 DOI: 10.1021/acssynbio.3c00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Spatial structure within microbial communities can provide nearly limitless opportunities for social interactions and are an important driver for evolution. As metabolites are often molecular signals, metabolite diffusion within microbial communities can affect the composition and dynamics of the community in a manner that can be challenging to deconstruct. We used encapsulation of a synthetic microbial community within microdroplets to investigate the effects of spatial structure and metabolite diffusion on population dynamics and to examine the effects of cheating by one member of the community. The synthetic community was composed of three strains: a "Producer" that makes the diffusible quorum sensing molecule (N-(3-oxododecanoyl)-l-homoserine lactone, C12-oxo-HSL) or AHL; a "Receiver" that is killed by AHL; and a Non-Producer or "cheater" that benefits from the extinction of the Receivers, but without the costs associated with the AHL synthesis. We demonstrate that despite rapid diffusion of AHL between microdroplets, the spatial structure imposed by the microdroplets allows a more efficient but transient enrichment of more rare and slower-growing Producer subpopulations. Eventually, the Non-Producer population drove the Producers to extinction. By including fluorescence-activated microdroplet sorting and providing sustained competition by the Receiver strain, we demonstrate a strategy for indirect enrichment of a rare and unlabeled Producer. The ability to screen and enrich metabolite Producers from a much larger population under conditions of rapid diffusion provides an important framework for the development of applications in synthetic ecology and biotechnology.
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Affiliation(s)
| | - Gaoyang Fan
- Department of Mathematics, University of Houston, Houston, Texas, 77204, United States
| | - Razan N Alnahhas
- Department of Biosciences, Rice University, Houston, Texas, 77005, United States
| | - Andrew J Hirning
- Department of Biosciences, Rice University, Houston, Texas, 77005, United States
| | - Matthew R Bennett
- Department of Biosciences, Rice University, Houston, Texas, 77005, United States
- Department of Bioengineering, Rice University, Houston, Texas, 77005, United States
| | - Yousif Shamoo
- Department of Biosciences, Rice University, Houston, Texas, 77005, United States
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8
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Fabrication of planar monolayer microreactor array for visual statistical analysis and droplet-based digital quantitative analysis in situ. Anal Bioanal Chem 2023; 415:627-637. [PMID: 36504285 DOI: 10.1007/s00216-022-04451-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 12/14/2022]
Abstract
Planar monolayer microreactor arrays (PMMRAs) make droplet-based numerical measurements and statistical analysis cheap and easy. However, PMMRAs are typically produced in complex microfluidic devices and, moreover, still requires stringent control to reduce droplet loss during heating. In this paper, a simple, reliable, and flexible method for fabricating PMMRAs in a 96-well plate is described in detail by using simple materials and low-cost equipment. The partitioned droplets spontaneously assemble into PMMRAs in the plates, and this distribution is maintained even after incubation. This is advantageous for in situ analysis based on an individual droplet in droplet digital loop-mediated isothermal amplification (ddLAMP) and does not require the transfer of positive droplets. Precise and reproducible quantification of classical swine fever virus (CSFV) extracts was executed in these PMMRAs to verify its availability. Our results demonstrate that the proposed approach not only provides a flexible and controllable execution scheme for droplet-based nucleic acid quantification in resource-limited laboratories but also opens new perspectives for numerous analytical and biochemical applications using droplets as versatile plastic microreactors.
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9
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Prabhakar RG, Fan G, Alnahhas RN, Hirning AJ, Bennett MR, Shamoo Y. Indirect enrichment of desirable, but less fit phenotypes, from a synthetic microbial community using microdroplet confinement. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.11.523444. [PMID: 36711600 PMCID: PMC9882018 DOI: 10.1101/2023.01.11.523444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Spatial structure within microbial communities can provide nearly limitless opportunities for social interactions and are an important driver for evolution. As metabolites are often molecular signals, metabolite diffusion within microbial communities can affect the composition and dynamics of the community in a manner that can be challenging to deconstruct. We used encapsulation of a synthetic microbial community within microdroplets to investigate the effects of spatial structure and metabolite diffusion on population dynamics and to examine the effects of cheating by one member of the community. The synthetic community was comprised of three strains: a 'Producer' that makes the diffusible quorum sensing molecule ( N -(3-Oxododecanoyl)-L-homoserine lactone, C12-oxo-HSL) or AHL; a 'Receiver' that is killed by AHL and a Non-Producer or 'cheater' that benefits from the extinction of the Receivers, but without the costs associated with the AHL synthesis. We demonstrate that despite rapid diffusion of AHL between microdroplets, the spatial structure imposed by the microdroplets allow a more efficient but transient enrichment of more rare and slower growing 'Producer' subpopulations. Eventually, the Non-Producer population drove the Producers to extinction. By including fluorescence-activated microdroplet sorting and providing sustained competition by the Receiver strain, we demonstrate a strategy for indirect enrichment of a rare and unlabeled Producer. The ability to screen and enrich metabolite Producers from a much larger population under conditions of rapid diffusion provides an important framework for the development of applications in synthetic ecology and biotechnology. Abstract Figure
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Affiliation(s)
| | - Gaoyang Fan
- Department of Mathematics, University of Houston, Houston, Texas, United States
| | - Razan N Alnahhas
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Andrew J Hirning
- Department of Biosciences, Rice University, Houston, United States
| | - Matthew R Bennett
- Department of Biosciences, Rice University, Houston, United States
- Department of Bioengineering, Rice University, Houston, United States
| | - Yousif Shamoo
- Department of Biosciences, Rice University, Houston, United States
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10
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Jiang Z, Shi H, Tang X, Qin J. Recent advances in droplet microfluidics for single-cell analysis. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2023.116932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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11
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A novel high-throughput approach for transforming filamentous fungi employing a droplet-based microfluidic platform. N Biotechnol 2022; 72:149-158. [PMID: 36442794 DOI: 10.1016/j.nbt.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/16/2022] [Accepted: 11/18/2022] [Indexed: 11/27/2022]
Abstract
Droplet-based microfluidic technology is a powerful tool for single-cell cultivation and rapid isolation of bacteria, yeasts and algae. However, it has been of limited use for studies of filamentous fungi due to the fast growth of their branched hyphae. The long regeneration time for fungal protoplasts and low-throughput screening methods are inherent problems for current genetic transformation techniques. Therefore, we have developed a novel droplet-based method for the filamentous fungus Trichoderma reesei expressing green fluorescent protein (GFP) as a marker. This approach presented several outstanding advantages over the traditional transformation method, including a 7-fold reduction in time for T. reesei protoplast regeneration, an 8-fold increase in regeneration frequency, and a screening speed of up to 8,000 droplets min-1. In this study, we encapsulated and incubated the gfp-transformed T. reesei protoplasts in droplets for 24 h, screened the droplets in a high-throughput assay, and eventually collected a transformant library with over 96 % of the candidates transformed with the marker gene. This versatile approach should make fungi more amenable to genetic manipulation and encourage strain improvements for industrial applications.
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12
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Laser-assisted bioprinting of microorganisms with hydrogel microdroplets: peculiarities of Ascomycota and Basidiomycota yeast transfer. World J Microbiol Biotechnol 2022; 39:29. [PMID: 36437388 DOI: 10.1007/s11274-022-03478-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/18/2022] [Indexed: 11/29/2022]
Abstract
Laser-assisted bioprinting of microbial cells by hydrogel microdroplets is a rapidly developing and promising field that can contribute to solving a number of issues in microbiology and biotechnology. To date, most research on the use of laser bioprinting for microorganism manipulation and sorting has focused on prokaryotes; the bioprinting of eukaryotic microorganisms is much less understood. The use of hydrogel allows solving two fundamental problems: creating comfortable environments for living microorganisms and imparting the necessary rheological properties of the gel for the stable transfer of microdroplets of a preset size. Two main problems were solved in this article. First, the parameters of the hydrogel based on hyaluronic acid and laser fluence to ensure stable transfer of single drops are selected. Second, possible differences in the bioprinting by hyaluronic acid hydrogel microdroplets with yeasts of various taxonomy (Ascomycota vs Basidiomycota), which form and do not form polysaccharide capsules and evaluated. We have performed laser induced forward transfer of 8 yeast species (Goffeauzyma gilvescens, Lipomyces lipofer, Lipomyces starkey, Pichia manshurica, Saitozyma podzolica, Schwanniomyces occidentalis var. occidentalis, Sterigmatosporidium polymorphum, Vanrija humicola) and assessed its viability based on colony formation on the nutrient medium. It is shown that after laser-induced transfer in hydrogel microdroplets the mean viability rate was 77% with some strains showing relatively high viability rates exceeding 90%. Effect of capsules presence on colony formation after laser bioprinting was not revealed. Differences in laser transfer of the yeast of various phyla were found-basidiomycetes formed a greater number of colonies than ascomycetes. The causes and mechanisms of these effects require detailed studies. The data obtained contributes to the knowledge about the bioprinting of eukaryotic microorganisms and can be useful in the studies of single microbial cells and inter-organism interactions.
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13
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Jouhten P, Konstantinidis D, Pereira F, Andrejev S, Grkovska K, Castillo S, Ghiachi P, Beltran G, Almaas E, Mas A, Warringer J, Gonzalez R, Morales P, Patil KR. Predictive evolution of metabolic phenotypes using model-designed environments. Mol Syst Biol 2022; 18:e10980. [PMID: 36201279 PMCID: PMC9536503 DOI: 10.15252/msb.202210980] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 11/04/2022] Open
Abstract
Adaptive evolution under controlled laboratory conditions has been highly effective in selecting organisms with beneficial phenotypes such as stress tolerance. The evolution route is particularly attractive when the organisms are either difficult to engineer or the genetic basis of the phenotype is complex. However, many desired traits, like metabolite secretion, have been inaccessible to adaptive selection due to their trade-off with cell growth. Here, we utilize genome-scale metabolic models to design nutrient environments for selecting lineages with enhanced metabolite secretion. To overcome the growth-secretion trade-off, we identify environments wherein growth becomes correlated with a secondary trait termed tacking trait. The latter is selected to be coupled with the desired trait in the application environment where the trait manifestation is required. Thus, adaptive evolution in the model-designed selection environment and subsequent return to the application environment is predicted to enhance the desired trait. We experimentally validate this strategy by evolving Saccharomyces cerevisiae for increased secretion of aroma compounds, and confirm the predicted flux-rerouting using genomic, transcriptomic, and proteomic analyses. Overall, model-designed selection environments open new opportunities for predictive evolution.
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Affiliation(s)
- Paula Jouhten
- European Molecular Biology LaboratoryHeidelbergGermany,VTT Technical Research Centre of Finland LtdEspooFinland,Department of Bioproducts and BiosystemsAalto UniversityEspooFinland
| | | | | | | | | | | | - Payam Ghiachi
- Department of Chemistry and Molecular BiologyUniversity of GothenburgGothenburgSweden
| | - Gemma Beltran
- Departament Bioquímica i Biotecnologia, Facultat d'EnologiaUniversitat Rovira i VirgiliTarragonaSpain
| | - Eivind Almaas
- Department of Biotechnology and Food ScienceNTNU – Norwegian University of Science and TechnologyTrondheimNorway
| | - Albert Mas
- Departament Bioquímica i Biotecnologia, Facultat d'EnologiaUniversitat Rovira i VirgiliTarragonaSpain
| | - Jonas Warringer
- Department of Chemistry and Molecular BiologyUniversity of GothenburgGothenburgSweden
| | - Ramon Gonzalez
- Instituto de Ciencias de la Vid y delVino (CSIC, Gobierno de la Rioja, Universidad de La Rioja) Finca La GrajeraLogroñoSpain
| | - Pilar Morales
- Instituto de Ciencias de la Vid y delVino (CSIC, Gobierno de la Rioja, Universidad de La Rioja) Finca La GrajeraLogroñoSpain
| | - Kiran R Patil
- European Molecular Biology LaboratoryHeidelbergGermany,Medical Research Council (MRC) Toxicology UnitUniversity of CambridgeCambridgeUK
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14
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Banks M, Johnson R, Giver L, Bryant G, Guo M. Industrial production of microbial protein products. Curr Opin Biotechnol 2022; 75:102707. [PMID: 35276510 DOI: 10.1016/j.copbio.2022.102707] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/09/2022] [Accepted: 02/17/2022] [Indexed: 01/24/2023]
Abstract
Microbial proteins provide a sustainable and nutritious alternative to traditional animal and plant-based proteins. Various strains have been demonstrated to generate biomass from a wide variety of substrates, from organic waste (e.g. banana peel) to gases (e.g. methane). Industrial production of microbial protein has proven difficult from both design (e.g. production rate) and regulatory (e.g. allergenicity of product) perspectives for both feed and food-grade products. Through use of low-cost microfluidics devices, early bioprocess design can be intensified, achieving high strain screening throughput with low titres. Integration of industrial waste streams (e.g. flue-gases, lignocellulosic residues) can reduce cost and carbon footprint of feedstock, while bespoke reactor design (e.g. Quorn's airlift U-loop fermenter) can remediate issues of low mass-transfer and product quality.
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Affiliation(s)
- Mason Banks
- Department of Engineering, Faculty of Natural Mathematical & Engineering Sciences, King's College London, Strand Campus, WC2R 2LS, UK
| | - Rob Johnson
- Quorn Foods, Station Road, Stokesley, North Yorkshire, TS9 7AB, UK
| | - Lori Giver
- Calysta, T3 Block, The Wilton Centre, Wilton, Redcar, TS10 4RF, UK
| | - Geoff Bryant
- Calysta, T3 Block, The Wilton Centre, Wilton, Redcar, TS10 4RF, UK
| | - Miao Guo
- Department of Engineering, Faculty of Natural Mathematical & Engineering Sciences, King's College London, Strand Campus, WC2R 2LS, UK.
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15
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Seo S, Disney-McKeethen S, Prabhakar RG, Song X, Mehta HH, Shamoo Y. Identification of Evolutionary Trajectories Associated with Antimicrobial Resistance Using Microfluidics. ACS Infect Dis 2022; 8:242-254. [PMID: 34962128 PMCID: PMC10022597 DOI: 10.1021/acsinfecdis.1c00564] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In vitro experimental evolution of pathogens to antibiotics is commonly used for the identification of clinical biomarkers associated with antibiotic resistance. Microdroplet emulsions allow exquisite control of spatial structure, species complexity, and selection microenvironments for such studies. We investigated the use of monodisperse microdroplets in experimental evolution. Using Escherichia coli adaptation to doxycycline, we examined how changes in environmental conditions such as droplet size, starting lambda value, selection strength, and incubation method affected evolutionary outcomes. We also examined the extent to which emulsions could reveal potentially new evolutionary trajectories and dynamics associated with antimicrobial resistance. Interestingly, we identified both expected and unexpected evolutionary trajectories including large-scale chromosomal rearrangements and amplification that were not observed in suspension culture methods. As microdroplet emulsions are well-suited for automation and provide exceptional control of conditions, they can provide a high-throughput approach for biomarker identification as well as preclinical evaluation of lead compounds.
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Affiliation(s)
- Seokju Seo
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
| | | | | | - Xinhao Song
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
| | - Heer H Mehta
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
| | - Yousif Shamoo
- Department of BioSciences, Rice University, Houston, Texas 77005, United States
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16
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Bakhtiari S, Manshadi MKD, Mansoorifar A, Beskok A. A Microfluidic Dielectric Spectroscopy System for Characterization of Biological Cells in Physiological Media. SENSORS (BASEL, SWITZERLAND) 2022; 22:463. [PMID: 35062423 PMCID: PMC8779508 DOI: 10.3390/s22020463] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/31/2021] [Accepted: 01/05/2022] [Indexed: 02/04/2023]
Abstract
Dielectric spectroscopy (DS) is a promising cell screening method that can be used for diagnostic and drug discovery purposes. The primary challenge of using DS in physiological buffers is the electrode polarization (EP) that overwhelms the impedance signal within a large frequency range. These effects further amplify with the miniaturization of the measurement electrodes. In this study, we present a microfluidic system and the associated equivalent circuit models for real-time measurements of cell membrane capacitance and cytoplasm resistance in physiological buffers with 10 s increments. The current device captures several hundreds of biological cells in individual microwells through gravitational settling and measures the system's impedance using microelectrodes covered with dendritic gold nanostructures. Using PC-3 cells (a highly metastatic prostate cancer cell line) suspended in cell growth media (CGM), we demonstrate stable measurements of cell membrane capacitance and cytoplasm resistance in the device for over 15 min. We also describe a consistent application of the equivalent circuit model, starting from the reference measurements used to determine the system parameters. The circuit model is tested using devices with varying dimensions, and the obtained cell parameters between different devices are nearly identical. Further analyses of the impedance data have shown that accurate cell membrane capacitance and cytoplasm resistance can be extracted using a limited number of measurements in the 5 MHz to 10 MHz range. This will potentially reduce the timescale required for real-time DS measurements below 1 s. Overall, the new microfluidic device can be used for the dielectric characterization of biological cells in physiological buffers for various cell screening applications.
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Affiliation(s)
| | | | | | - Ali Beskok
- Mechanical Engineering Department, Southern Methodist University, Dallas, TX 75275, USA; (S.B.); (M.K.D.M.); (A.M.)
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17
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Tran TM, Kim SC, Modavi C, Abate AR. Robotic automation of droplet microfluidics. BIOMICROFLUIDICS 2022; 16:014102. [PMID: 35145570 PMCID: PMC8816516 DOI: 10.1063/5.0064265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
Droplet microfluidics enables powerful analytic capabilities but often requires workflows involving macro- and microfluidic processing steps that are cumbersome to perform manually. Here, we demonstrate the automation of droplet microfluidics with commercial fluid-handling robotics. The workflows incorporate common microfluidic devices including droplet generators, mergers, and sorters and utilize the robot's native capabilities for thermal control, incubation, and plate scanning. The ability to automate microfluidic devices using commercial fluid handling will speed up the integration of these methods into biological workflows.
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Affiliation(s)
- Tuan M. Tran
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California 94158, USA
| | - Samuel C. Kim
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California 94158, USA
| | - Cyrus Modavi
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California 94158, USA
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18
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Yuan H, Tu R, Tong X, Lin Y, Zhang Y, Wang Q. OUP accepted manuscript. J Ind Microbiol Biotechnol 2022; 49:6544676. [PMID: 35259275 PMCID: PMC9142201 DOI: 10.1093/jimb/kuac007] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 02/20/2022] [Indexed: 11/12/2022]
Abstract
Droplet-based microfluidics has emerged as a powerful tool for single-cell screening with ultrahigh throughput, but its widespread application remains limited by the accessibility of a droplet microfluidic high-throughput screening (HTS) platform, especially to common laboratories having no background in microfluidics. Here, we first developed a microfluidic HTS platform based on fluorescence-activated droplet sorting technology. This platform allowed (i) encapsulation of single cells in monodisperse water-in-oil droplets; (ii) cell growth and protein production in droplets; and (iii) sorting of droplets based on their fluorescence intensities. To validate the platform, a model selection experiment of a binary mixture of Bacillus strains was performed, and a 45.6-fold enrichment was achieved at a sorting rate of 300 droplets per second. Furthermore, we used the platform for the selection of higher α-amylase-producing Bacillus licheniformis strains from a mutant library generated by atmospheric and room temperature plasma mutagenesis, and clones displaying over 50% improvement in α-amylase productivity were isolated. This droplet screening system could be applied to the engineering of other industrially valuable strains.
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Affiliation(s)
| | | | - Xinwei Tong
- Shandong Longkete Enzyme Preparations Co., Ltd, Linyi 276400, China
| | - Yuping Lin
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin 300308, China
| | - Yuanyuan Zhang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin 300308, China
| | - Qinhong Wang
- Correspondence should be addressed to: Qinhong Wang. Phone: +86-22-24821950. Fax: +86-22-24821950. E-mail:
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19
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Kerk YJ, Jameel A, Xing X, Zhang C. Recent advances of integrated microfluidic suspension cell culture system. ENGINEERING BIOLOGY 2021; 5:103-119. [PMID: 36970555 PMCID: PMC9996741 DOI: 10.1049/enb2.12015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 11/19/2022] Open
Abstract
Microfluidic devices with superior microscale fluid manipulation ability and large integration flexibility offer great advantages of high throughput, parallelisation and multifunctional automation. Such features have been extensively utilised to facilitate cell culture processes such as cell capturing and culturing under controllable and monitored conditions for cell-based assays. Incorporating functional components and microfabricated configurations offered different levels of fluid control and cell manipulation strategies to meet diverse culture demands. This review will discuss the advances of single-phase flow and droplet-based integrated microfluidic suspension cell culture systems and their applications for accelerated bioprocess development, high-throughput cell selection, drug screening and scientific research to insight cell biology. Challenges and future prospects for this dynamically developing field are also highlighted.
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Affiliation(s)
- Yi Jing Kerk
- Institute of Biochemical EngineeringDepartment of Chemical Engineering, Tsinghua UniversityBeijingChina
| | - Aysha Jameel
- Institute of Biochemical EngineeringDepartment of Chemical Engineering, Tsinghua UniversityBeijingChina
- MOE Key Laboratory of Industrial BiocatalysisDepartment of Chemical Engineering, Tsinghua UniversityBeijingChina
| | - Xin‐Hui Xing
- Institute of Biochemical EngineeringDepartment of Chemical Engineering, Tsinghua UniversityBeijingChina
- MOE Key Laboratory of Industrial BiocatalysisDepartment of Chemical Engineering, Tsinghua UniversityBeijingChina
- Center for Synthetic and Systems BiologyTsinghua UniversityBeijingChina
| | - Chong Zhang
- Institute of Biochemical EngineeringDepartment of Chemical Engineering, Tsinghua UniversityBeijingChina
- MOE Key Laboratory of Industrial BiocatalysisDepartment of Chemical Engineering, Tsinghua UniversityBeijingChina
- Center for Synthetic and Systems BiologyTsinghua UniversityBeijingChina
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20
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Abstract
Enzymes are represented across a vast space of protein sequences and structural forms and have activities that far exceed the best chemical catalysts; however, engineering them to have novel or enhanced activity is limited by technologies for sensing product formation. Here, we describe a general and scalable approach for characterizing enzyme activity that uses the metabolism of the host cell as a biosensor by which to infer product formation. Since different products consume different molecules in their synthesis, they perturb host metabolism in unique ways that can be measured by mass spectrometry. This provides a general way by which to sense product formation, to discover unexpected products and map the effects of mutagenesis. The testing of engineered enzymes represents a bottleneck. Here the authors report a screening method combining microfluidics and mass spectrometry, to map the catalysis of a mutated enzyme, characterise the range of products generated and recover the sequences of variants with desired activities.
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21
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Liu H, Piper JA, Li M. Rapid, Simple, and Inexpensive Spatial Patterning of Wettability in Microfluidic Devices for Double Emulsion Generation. Anal Chem 2021; 93:10955-10965. [PMID: 34323465 DOI: 10.1021/acs.analchem.1c01861] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Water-in-oil-in-water (w/o/w) double emulsion (DE) encapsulation has been widely used as a promising platform technology for various applications in the fields of food, cosmetics, pharmacy, chemical engineering, materials science, and synthetic biology. Unfortunately, DEs formed by conventional emulsion generation approaches in most cases are highly polydisperse, making them less desirable for quantitative assays, controlled biomaterial synthesis, and entrapped ingredient release. Microfluidic devices can generate monodisperse DEs with controllable size, morphology, and production rate, but these generally require multistep fabrication processes and use of different solvents or bulky external instrumentation to pattern channel wettability. To overcome these limitations, we propose a rapid, simple, and inexpensive method to spatially pattern wettability in microfluidic devices for the continuous generation of monodisperse DEs. This is achieved by applying corona-plasma treatment to a select zone of the microchannel surface aided by a custom-designed corona resistance microchannel to strictly confine the plasma-treatment zone in a single polydimethylsiloxane (PDMS) microfluidic device. The properties of PDMS channel surfaces and key microchannel regions for DE generation are characterized under different levels of treatment. The size, shell thickness, and number of inner cores of generated DEs are shown to be highly controllable by tuning the phase flow rate ratios. Using DEs as templates, we successfully achieve a one-step generation and collection of gelatin microgels. Additionally, we demonstrate the biological capability of generated DEs by flow cytometric screening of the encapsulation and growth of yeast cells within DEs. We expect that the proposed approach will be widely used to create microfluidic devices with more complex wettability patterns.
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Affiliation(s)
- Hangrui Liu
- ARC Centre of Excellence for Nanoscale BioPhotonics, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia.,Department of Physics and Astronomy, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia
| | - James A Piper
- ARC Centre of Excellence for Nanoscale BioPhotonics, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia.,Department of Physics and Astronomy, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia
| | - Ming Li
- School of Engineering, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia.,Biomolecular Discovery Research Centre, Macquarie University, Balaclava Road, North Ryde, New South Wales 2109, Australia
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22
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Droplet-based microfluidic platform for high-throughput screening of Streptomyces. Commun Biol 2021; 4:647. [PMID: 34059751 PMCID: PMC8166820 DOI: 10.1038/s42003-021-02186-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 05/05/2021] [Indexed: 12/20/2022] Open
Abstract
Streptomyces are one of the most important industrial microorganisms for the production of proteins and small-molecule drugs. Previously reported flow cytometry-based screening methods can only screen spores or protoplasts released from mycelium, which do not represent the filamentous stationary phase Streptomyces used in industrial cultivation. Here we show a droplet-based microfluidic platform to facilitate more relevant, reliable and rapid screening of Streptomyces mycelium, and achieved an enrichment ratio of up to 334.2. Using this platform, we rapidly characterized a series of native and heterologous constitutive promoters in Streptomyces lividans 66 in droplets, and efficiently screened out a set of engineered promoter variants with desired strengths from two synthetic promoter libraries. We also successfully screened out several hyperproducers of cellulases from a random S. lividans 66 mutant library, which had 69.2–111.4% greater cellulase production than the wild type. Our method provides a fast, simple, and powerful solution for the industrial engineering and screening of Streptomyces in more industry-relevant conditions. Streptomyces are an important filamentous bacterium genus in industry, but most of the high-throughput techniques so far can only separate spores or protoplasts. Tu et al. develop an encapsulating method that allows screening of Streptomyces in the filamentous, stationary phase.
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23
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Han Y, Xu X, Liu F, Wei W, Liu Z. Novel Microfluidic Device for the Preparation of Multiple Microproducts. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c01094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yu Han
- R&D Institute of Fluid and Powder Engineering, Dalian University of Technology, Dalian 116024, China
| | - Xiaofei Xu
- R&D Institute of Fluid and Powder Engineering, Dalian University of Technology, Dalian 116024, China
| | - Fengxia Liu
- R&D Institute of Fluid and Powder Engineering, Dalian University of Technology, Dalian 116024, China
| | - Wei Wei
- R&D Institute of Fluid and Powder Engineering, Dalian University of Technology, Dalian 116024, China
| | - Zhijun Liu
- R&D Institute of Fluid and Powder Engineering, Dalian University of Technology, Dalian 116024, China
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24
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van Tatenhove-Pel RJ, Rijavec T, Lapanje A, van Swam I, Zwering E, Hernandez-Valdes JA, Kuipers OP, Picioreanu C, Teusink B, Bachmann H. Microbial competition reduces metabolic interaction distances to the low µm-range. THE ISME JOURNAL 2021; 15:688-701. [PMID: 33077887 PMCID: PMC8027890 DOI: 10.1038/s41396-020-00806-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 09/21/2020] [Accepted: 10/02/2020] [Indexed: 01/12/2023]
Abstract
Metabolic interactions between cells affect microbial community compositions and hence their function in ecosystems. It is well-known that under competition for the exchanged metabolite, concentration gradients constrain the distances over which interactions can occur. However, interaction distances are typically quantified in two-dimensional systems or without accounting for competition or other metabolite-removal, conditions which may not very often match natural ecosystems. We here analyze the impact of cell-to-cell distance on unidirectional cross-feeding in a three-dimensional aqueous system with competition for the exchanged metabolite. Effective interaction distances were computed with a reaction-diffusion model and experimentally verified by growing a synthetic consortium of 1 µm-sized metabolite producer, receiver, and competitor cells in different spatial structures. We show that receivers cannot interact with producers located on average 15 µm away from them, as product concentration gradients flatten close to producer cells. We developed an aggregation protocol and varied the receiver cells' product affinity, to show that within producer-receiver aggregates even low-affinity receiver cells could interact with producers. These results show that competition or other metabolite-removal of a public good in a three-dimensional system reduces metabolic interaction distances to the low µm-range, highlighting the importance of concentration gradients as physical constraint for cellular interactions.
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Affiliation(s)
- Rinke J van Tatenhove-Pel
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV, Amsterdam, The Netherlands
| | - Tomaž Rijavec
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000, Ljubljana, Slovenia
| | - Aleš Lapanje
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000, Ljubljana, Slovenia
| | - Iris van Swam
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV, Amsterdam, The Netherlands
| | - Emile Zwering
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV, Amsterdam, The Netherlands
| | - Jhonatan A Hernandez-Valdes
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG, Groningen, The Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG, Groningen, The Netherlands
| | - Cristian Picioreanu
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ, Delft, The Netherlands
| | - Bas Teusink
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV, Amsterdam, The Netherlands
| | - Herwig Bachmann
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV, Amsterdam, The Netherlands.
- NIZO Food Research, Kernhemseweg 2, 6718ZB, Ede, The Netherlands.
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25
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van Tatenhove-Pel RJ, Zwering E, Boreel DF, Falk M, van Heerden JH, Kes MBMJ, Kranenburg CI, Botman D, Teusink B, Bachmann H. Serial propagation in water-in-oil emulsions selects for Saccharomyces cerevisiae strains with a reduced cell size or an increased biomass yield on glucose. Metab Eng 2021; 64:1-14. [PMID: 33418011 DOI: 10.1016/j.ymben.2020.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 11/26/2020] [Accepted: 12/15/2020] [Indexed: 11/19/2022]
Abstract
In S. cerevisiae and many other micro-organisms an increase in metabolic efficiency (i.e. ATP yield on carbon) is accompanied by a decrease in growth rate. From a fundamental point of view, studying these yield-rate trade-offs provides insight in for example microbial evolution and cellular regulation. From a biotechnological point of view, increasing the ATP yield on carbon might increase the yield of anabolic products. We here aimed to select S. cerevisiae mutants with an increased biomass yield. Serial propagation of individual cells in water-in-oil emulsions previously enabled the selection of lactococci with increased biomass yields, and adapting this protocol for yeast allowed us to enrich an engineered Crabtree-negative S. cerevisiae strain with a high biomass yield on glucose. When we started the selection with an S. cerevisiae deletion collection, serial propagation in emulsion enriched hxk2Δ and reg1Δ strains with an increased biomass yield on glucose. Surprisingly, a tps1Δ strain was highly abundant in both emulsion- and suspension-propagated populations. In a separate experiment we propagated a chemically mutagenized S. cerevisiae population in emulsion, which resulted in mutants with a higher cell number yield on glucose, but no significantly changed biomass yield. Genome analyses indicate that genes involved in glucose repression and cell cycle processes play a role in the selected phenotypes. The repeated identification of mutations in genes involved in glucose-repression indicates that serial propagation in emulsion is a valuable tool to study metabolic efficiency in S. cerevisiae.
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Affiliation(s)
- Rinke Johanna van Tatenhove-Pel
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV Amsterdam, the Netherlands
| | - Emile Zwering
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV Amsterdam, the Netherlands
| | - Daan Floris Boreel
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV Amsterdam, the Netherlands
| | - Martijn Falk
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV Amsterdam, the Netherlands
| | - Johan Hendrik van Heerden
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV Amsterdam, the Netherlands
| | - Mariah B M J Kes
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV Amsterdam, the Netherlands
| | - Cindy Iris Kranenburg
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV Amsterdam, the Netherlands
| | - Dennis Botman
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV Amsterdam, the Netherlands
| | - Bas Teusink
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV Amsterdam, the Netherlands
| | - Herwig Bachmann
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences, VU University Amsterdam, de Boelelaan 1108, 1081HV Amsterdam, the Netherlands; NIZO Food Research, Kernhemseweg 2, 6718ZB, Ede, the Netherlands.
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26
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Hernandez-Valdes JA, aan de Stegge M, Hermans J, Teunis J, van Tatenhove-Pel RJ, Teusink B, Bachmann H, Kuipers OP. Enhancement of amino acid production and secretion by Lactococcus lactis using a droplet-based biosensing and selection system. Metab Eng Commun 2020; 11:e00133. [PMID: 32551230 PMCID: PMC7292884 DOI: 10.1016/j.mec.2020.e00133] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 01/08/2023] Open
Abstract
Amino acids are attractive metabolites for the pharmaceutical and food industry field. On one hand, the construction of microbial cell factories for large-scale production aims to satisfy the demand for amino acids as bulk biochemical. On the other hand, amino acids enhance flavor formation in fermented foods. Concerning the latter, flavor formation in dairy products, such as cheese is associated with the presence of lactic acid bacteria (LAB). In particular, Lactococcus lactis, one of the most important LAB, is used as a starter culture in fermented foods. The proteolytic activity of some L. lactis strains results in peptides and amino acids, which are flavor compounds or flavor precursors. However, it is still a challenge to isolate bacterial cells with enhanced amino acid production and secretion activity. In this work, we developed a growth-based sensor strain to detect the essential amino acids isoleucine, leucine, valine, histidine and methionine. Amino acids are metabolites that can be secreted by some bacteria. Therefore, our biosensor allowed us to identify wild-type L. lactis strains that naturally secrete amino acids, by using co-cultures of the biosensor strain with potential amino acid producing strains. Subsequently, we used this biosensor in combination with a droplet-based screening approach, and isolated three mutated L. lactis IPLA838 strains with 5-10 fold increased amino acid-secretion compared to the wild type. Genome re-sequencing revealed mutations in genes encoding proteins that participate in peptide uptake and peptide degradation. We argue that an unbalance in the regulation of amino acid levels as a result of these gene mutations may drive the accumulation and secretion of these amino acids. This biosensing system tackles the problem of selection for overproduction of secreted molecules, which requires the coupling of the product to the producing cell in the droplets.
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Affiliation(s)
- Jhonatan A. Hernandez-Valdes
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747, AG, Groningen, the Netherlands
| | - Myrthe aan de Stegge
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747, AG, Groningen, the Netherlands
| | - Jos Hermans
- Analytical Biochemistry, Department of Pharmacy, University of Groningen, Antonius Deusinglaan 1, Groningen, 9713, AV, the Netherlands
| | - Johan Teunis
- Faculty of Medical Sciences, Department of Pathology and Medical Biology, Hanzeplein 1, 9713, GZ, Groningen, the Netherlands
| | - Rinke J. van Tatenhove-Pel
- Systems Bioinformatics, Amsterdam Institute for Molecules, Medicines and Systems, VU University Amsterdam, de Boelelaan 1108, 1081, HV, Amsterdam, the Netherlands
| | - Bas Teusink
- Systems Bioinformatics, Amsterdam Institute for Molecules, Medicines and Systems, VU University Amsterdam, de Boelelaan 1108, 1081, HV, Amsterdam, the Netherlands
| | - Herwig Bachmann
- Systems Bioinformatics, Amsterdam Institute for Molecules, Medicines and Systems, VU University Amsterdam, de Boelelaan 1108, 1081, HV, Amsterdam, the Netherlands
- NIZO Food Research, Kernhemseweg 2, 6718, ZB, Ede, the Netherlands
| | - Oscar P. Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747, AG, Groningen, the Netherlands
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Biosensor-enabled droplet microfluidic system for the rapid screening of 3-dehydroshikimic acid produced in Escherichia coli. J Ind Microbiol Biotechnol 2020; 47:1155-1160. [PMID: 32980986 DOI: 10.1007/s10295-020-02316-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/21/2020] [Indexed: 12/21/2022]
Abstract
Genetically encoded biosensors are powerful tools used to screen metabolite-producing microbial strains. Traditionally, biosensor-based screening approaches also use fluorescence-activated cell sorting (FACS). However, these approaches are limited by the measurement of intracellular fluorescence signals in single cells, rather than the signals associated with populations comprising multiple cells. This characteristic reduces the accuracy of screening because of the variability in signal levels among individual cells. To overcome this limitation, we introduced an approach that combined biosensors with droplet microfluidics (i.e., fluorescence-activated droplet sorting, FADS) to detect labeled cells at a multi-copy level and in an independent droplet microenvironment. We used our previously reported genetically encoded biosensor, 3-dehydroshikimic acid (3-DHS), as a model with which to establish the biosensor-based FADS screening method. We then characterized and compared the effects of the sorting method on the biosensor-based screening system by subjecting the same mutant library to FACS and FADS. Notably, our developed biosensor-enabled, droplet microfluidics-based FADS screening system yielded an improved positive mutant enrichment rate and increased productivity by the best mutant, compared with the single-cell FACS system. In conclusion, the combination of a biosensor and droplet microfluidics yielded a more efficient screening method that could be applied to the biosensor-based high-throughput screening of other metabolites.
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Cao M, Tran VG, Zhao H. Unlocking nature's biosynthetic potential by directed genome evolution. Curr Opin Biotechnol 2020; 66:95-104. [PMID: 32721868 DOI: 10.1016/j.copbio.2020.06.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/22/2020] [Accepted: 06/22/2020] [Indexed: 01/22/2023]
Abstract
Microorganisms have been increasingly explored as microbial cell factories for production of fuels, chemicals, drugs, and materials. Among the various metabolic engineering strategies, directed genome evolution has emerged as one of the most powerful tools to unlock the full biosynthetic potential of microorganisms. Here we summarize the directed genome evolution strategies that have been developed in recent years, including adaptive laboratory evolution and various targeted genome-scale engineering strategies, and discuss their applications in basic and applied biological research.
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Affiliation(s)
- Mingfeng Cao
- Department of Chemical and Biomolecular Engineering, U.S. Department of Energy Center for Bioenergy and Bioproducts Innovation (CABBI), Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Vinh G Tran
- Department of Chemical and Biomolecular Engineering, U.S. Department of Energy Center for Bioenergy and Bioproducts Innovation (CABBI), Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, U.S. Department of Energy Center for Bioenergy and Bioproducts Innovation (CABBI), Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Departments of Chemistry, Biochemistry, and Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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Schirmer M, Wink K, Ohla S, Belder D, Schmid A, Dusny C. Conversion Efficiencies of a Few Living Microbial Cells Detected at a High Throughput by Droplet-Based ESI-MS. Anal Chem 2020; 92:10700-10708. [DOI: 10.1021/acs.analchem.0c01839] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Martin Schirmer
- Helmholtz Centre for Environmental Research−UFZ Leipzig, Leipzig 04318, Germany
| | - Konstantin Wink
- Institute of Analytical Chemistry, Leipzig University, Leipzig 04103, Germany
| | - Stefan Ohla
- Institute of Analytical Chemistry, Leipzig University, Leipzig 04103, Germany
| | - Detlev Belder
- Institute of Analytical Chemistry, Leipzig University, Leipzig 04103, Germany
| | - Andreas Schmid
- Helmholtz Centre for Environmental Research−UFZ Leipzig, Leipzig 04318, Germany
| | - Christian Dusny
- Helmholtz Centre for Environmental Research−UFZ Leipzig, Leipzig 04318, Germany
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