Label-Free Analysis and Sorting of Microalgae and Cyanobacteria in Microdroplets by Intrinsic Chlorophyll Fluorescence for (...)

http://pubs.acs.org/doi/abs/10.1021/acs.analchem.6b02364

Roshni J. Best†‡, Jan J. Lyczakowski†, Sara Abalde-Cela†, Ziyi Yu†, Chris Abell*†, and Alison G. Smith*‡

† Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K.

‡ Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, U.K.

Abstract

Microalgae and cyanobacteria are promising organisms for sustainable biofuel production, but several challenges remain to make this economically viable, including identification of optimized strains with high biomass productivity. Here we report on a novel methodology for the label-free screening and sorting of cyanobacteria and microalgae in a microdroplet platform. We show for the first time that chlorophyll fluorescence can be used to measure differences in biomass between populations of picoliter microdroplets containing different species of cyanobacteria, Synechocystis PCC 6803 and Synechococcus PCC 7002, which exhibit different growth dynamics in bulk culture. The potential and robustness of this label-free screening approach is further demonstrated by the screening and sorting of cells of the green alga Chlamydomonas reinhardtii encapsulated in droplets.