A Gelatin Microdroplet Platform for High-Throughput Sorting of Hyperproducing Single-Cell-Derived Microalgal Clones

Ming Li; Mark van Zee; Carson T Riche; Bobby Tofig; Sean D Gallaher; Sabeeha S Merchant; Robert Damoiseaux; Keisuke Goda; Dino Di Carlo

doi:10.1002/smll.201803315

A Gelatin Microdroplet Platform for High-Throughput Sorting of Hyperproducing Single-Cell-Derived Microalgal Clones

Small. 2018 Nov;14(44):e1803315. doi: 10.1002/smll.201803315. Epub 2018 Oct 4.

Authors

Ming Li^{1

2}, Mark van Zee¹, Carson T Riche¹, Bobby Tofig³, Sean D Gallaher⁴, Sabeeha S Merchant⁴, Robert Damoiseaux^{3

5}, Keisuke Goda^{6

7

8}, Dino Di Carlo^{1

3

9}

Affiliations

¹ Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
² School of Engineering, Macquarie University, Sydney, NSW, 2122, Australia.
³ California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
⁴ Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
⁵ Department of Molecular and Medicinal Pharmacology, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
⁶ Department of Chemistry, University of Tokyo, Tokyo, 113-8655, Japan.
⁷ Japan Science and Technology Agency, Kawaguchi, 332-0012, Japan.
⁸ Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
⁹ California NanoSystems Institute, Jonsson Comprehensive Cancer Centre, University of California, Los Angeles, Los Angeles, CA, 90095, USA.

PMID: 30369052
DOI: 10.1002/smll.201803315

Abstract

Microalgae are an attractive feedstock organism for sustainable production of biofuels, chemicals, and biomaterials, but the ability to rationally engineer microalgae to enhance production has been limited. To enable the evolution-based selection of new hyperproducing variants of microalgae, a method is developed that combines phase-transitioning monodisperse gelatin hydrogel droplets with commercial flow cytometric instruments for high-throughput screening and selection of clonal populations of cells with desirable properties, such as high lipid productivity per time traced over multiple cell cycles. It is found that gelatin microgels enable i) the growth and metabolite (e.g., chlorophyll and lipids) production of single microalgal cells within the compartments, ii) infusion of fluorescent reporter molecules into the hydrogel matrices following a sol-gel transition, iii) selection of high-producing clonal populations of cells using flow cytometry, and iv) cell recovery under mild conditions, enabling regrowth after sorting. This user-friendly method is easily integratable into directed cellular evolution pipelines for strain improvement and can be adopted for other applications that require high-throughput processing, e.g., cellular secretion phenotypes and intercellular interactions.

Keywords: droplet microfluidics; high-throughput screening and sorting; microalgal biomass and biofuels; single-cell analysis.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Biofuels
Biomass
Gelatin / chemistry*
Microalgae / metabolism*
Microfluidics / methods*

Substances

Biofuels
Gelatin