Enzyme-mediated hydrogel encapsulation of single cells for high-throughput screening and directed evolution of oxidoreductases

Vanella, Rosario and Ta, Duy Tien and Nash, Michael A.. (2019) Enzyme-mediated hydrogel encapsulation of single cells for high-throughput screening and directed evolution of oxidoreductases. Biotechnology and bioengineering. pp. 1-9.

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Official URL: https://edoc.unibas.ch/71288/

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Directed evolution of oxidoreductases to improve their catalytic properties is being ardently pursued in the industrial, biotechnological, and biopharma sectors. Hampering this pursuit are current enzyme screening methods that are limited in terms of throughput, cost, time, and complexity. We present a directed evolution strategy that allows for large-scale one-pot screening of glucose oxidase (GOx) enzyme libraries in well-mixed homogeneous solution. We used GOx variants displayed on the outer cell wall of yeasts to initiate a cascade reaction with horseradish peroxidase (HRP), resulting in peroxidase-mediated phenol cross-coupling and encapsulation of individual cells in well-defined fluorescent alginate hydrogel shells within ~10 min in mixed cell suspensions. Following application of denaturing stress to whole-cell GOx libraries, only cells displaying GOx variants with enhanced stability or catalytic activity were able to carry out the hydrogel encapsulation reaction. Fluorescence-activated cell sorting was then used to isolate the enhanced variants. We characterized three of the newly evolved Aspergillus niger GOx enzyme sequences and found up to ~5-fold higher specific activity, enhanced thermal stability, and differentiable glycosylation patterns. By coupling intracellular gene expression with the rapid formation of an extracellular hydrogel capsule, our system improves high-throughput screening for directed evolution of H; 2; O; 2; -producing enzymes many folds.
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Synthetic Systems (Nash)
UniBasel Contributors:Nash, Michael and Vanella, Rosario and Ta, Duy Tien
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:15 Oct 2019 13:52
Deposited On:22 Aug 2019 13:53

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