Abstract
The application of microfluidic technologies to microalgal research is particularly appealing since these approaches allow the precise control of the extracellular environment and offer a high-throughput approach to studying dynamic cellular processes. To expand the portfolio of applications, here we present a droplet-based microfluidic method for analysis and screening of Phaeodactylum tricornutum and Nannochloropsis gaditana, which can be integrated into a genetic transformation workflow. Following encapsulation of single cells in picolitre-sized droplets, fluorescence signals arising from each cell can be used to assess its phenotypic state. In this work, the chlorophyll fluorescence intensity of each cell was quantified and used to identify populations of P. tricornutum cells grown in different light conditions. Further, individual P. tricornutum or N. gaditana cells engineered to express green fluorescent protein were distinguished and sorted from wild-type cells. This has been exploited as a rapid screen for transformed cells within a population, bypassing a major bottleneck in algal transformation workflows and offering an alternative strategy for the identification of genetically modified strains.
Highlights
Considerable attention has been directed recently to the exploitation of microalgae as a sustainable source for autotrophic bioproduction of food, fuels, and especially high value products such as long-chain polyunsaturated fatty acids, terpenoids, pigments, and therapeutic proteins [1,2,3,4]
To monitor the growth of individual cells of P. tricornutum and N. gaditana in microdroplets, cells grown in f/2 medium were encap sulated in microdroplets with an average diameter of 50 μm with the aim of having no more than one cell per droplet
The intracellular chlorophyll and green fluorescent protein (GFP) fluorescence of both P. tricornutum and N. gaditana cells encapsulated in microdroplets can be analysed to discriminate between individual cells
Summary
Considerable attention has been directed recently to the exploitation of microalgae as a sustainable source for autotrophic bioproduction of food, fuels, and especially high value products such as long-chain polyunsaturated fatty acids, terpenoids, pigments, and therapeutic proteins [1,2,3,4]. The last decade has witnessed dramatic progress in microalgal genetic engineering to improve the production of valuable compounds, the isolation and analysis of highperforming strains is still labour-intensive and time-consuming. Whilst basic tools for genetic engineering such as selectable markers, reporters, and promoter elements are available [6,7,8], the identification of genetically-modified strains is a slow process. The re covery of transformed lines can take several weeks as colonies need to grow to a sufficient size on selective plates. Since inte gration of the transgene typically occurs at random loci in the nuclear genome, the level and stability of transgene expression can vary significantly amongst transformant lines [9]. Many lines need to be analysed for the stable expression of the transgene and evaluated for the desired phenotypic change
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
