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Alex Wong CF, van Vliet L, Bhujbal SV, Guo C, Sletmoen M, Stokke BT, Hollfelder F, Lale R. A Titratable Cell Lysis-on-Demand System for Droplet-Compartmentalized Ultrahigh-Throughput Screening in Functional Metagenomics and Directed Evolution. ACS Synth Biol 2021; 10:1882-1894. [PMID: 34260196 PMCID: PMC8383311 DOI: 10.1021/acssynbio.1c00084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Water-in-oil emulsion
droplets are an attractive format for ultrahigh-throughput
screening in functional metagenomics and directed evolution applications
that allow libraries with more than 107 members to be characterized
in a day. Single library members are compartmentalized in droplets
that are generated in microfluidic devices and tested for the presence
of target biocatalysts. The target proteins can be produced intracellularly,
for example, in bacterial hosts in-droplet cell lysis is therefore
necessary to allow the enzymes to encounter the substrate to initiate
an activity assay. Here, we present a titratable lysis-on-demand (LoD)
system enabling the control of the cell lysis rate in Escherichia
coli. We demonstrate that the rate of cell lysis can be controlled
by adjusting the externally added inducer concentration. This LoD
system is evaluated both at the population level (by optical density
measurements) and at the single-cell level (on single-cell arrays
and in alginate microbeads). Additionally, we validate the LoD system
by droplet screening of a phosphotriesterase expressed from E. coli, with cell lysis triggered by inducer concentrations
in the μM range. The LoD system yields sufficient release of
the intracellularly produced enzymes to bring about a detectable quantity
of product (measured by fluorescence in flow cytometry of double emulsions),
while leaving viable cells for the downstream recovery of the genetic
material.
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Affiliation(s)
- Che Fai Alex Wong
- Department of Biotechnology, Faculty of Natural Sciences, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Liisa van Vliet
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom
| | - Swapnil Vilas Bhujbal
- Department of Biotechnology, Faculty of Natural Sciences, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Chengzhi Guo
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom
| | - Marit Sletmoen
- Department of Biotechnology, Faculty of Natural Sciences, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Bjørn Torger Stokke
- Department of Physics, Faculty of Natural Sciences, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, United Kingdom
| | - Rahmi Lale
- Department of Biotechnology, Faculty of Natural Sciences, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
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