Ultrahigh-Throughput Enzyme Engineering and Discovery in In Vitro Compartments

Area of Science:

• Biochemistry
• Molecular Biology
• Biotechnology

Background:

• Enzyme discovery relies on experimental screening of candidate libraries.
• Screening capacity is a major limitation in identifying novel and improved biocatalysts.
• Traditional methods like 96-well plates are insufficient for the scale required.

Purpose of the Study:

• To review the practicalities of droplet screening for enzyme discovery and kinetic characterization.
• To highlight the advantages of droplet microfluidics over conventional screening methods.
• To discuss the integration of droplet screening with next-generation sequencing and deep learning for directed evolution.

Main Methods:

• Utilizing water-in-oil emulsion droplets as picoliter-volume in vitro compartments.
• Employing automated microfluidic devices for droplet generation and integration into modular workflows.
• Implementing multistep screening protocols with various detection modes at kHz frequencies.

Main Results:

• Droplet screening achieves >10^7-fold volume reduction compared to 96-well plates.
• Enables sorting of >10^7 variants per day, covering all enzyme commission (EC) number classes.
• Facilitates detailed kinetic characterization and integration with advanced computational methods.

Conclusions:

• Droplet microfluidics offers a transformative approach to biocatalyst screening and discovery.
• This technology significantly expands screening capacity, accelerating research and development.
• Interfacing droplet screening with next-generation sequencing and deep learning revolutionizes directed evolution strategies.