Synthetic Biology and Microfluidics to Engineer Lipid Metabolism in Marine Algae

Marine microalgae like the diatom Phaeodactylum tricornutum are exciting biotechnological chassis as they can grow to high density on non-potable water sources. The availability of genomic resources and the ability to accumulate naturally large amounts of lipids in form of triacylglycerols (TAGs) make P. tricornutum an interesting host to produce novel fatty acids or valuable oils for food and feed. Over the last few years, we and others have developed a range of established and novel DNA parts (constitutive and inducible promoters, 5UTRs, 3UTRs and target peptides) for P. tricornutum based on the MoClo syntax and Golden Gate assembly. A similar toolkit has been recently established for the green algae Chlamydomonas reinhardtii (Crozet et al., 2018). Using these DNA parts, we have assembled molecular devices to manipulate the lipid metabolism in P. tricornutum. We will present data on the overexpression of diacylglycerol acyltransferases (DGATs) and phospholipid:diacylglycerol acyltransferase (PDAT), enzymes involved in TAG synthesis. In addition, we are combining metabolic engineering with state-of-the-art microfluidic devices for the encapsulation and growth of wildtype and transformed microalgae cells in microdroplets, allowing the analysis of single cells and the screening of them in a high-throughput manner. The sorting technology can be used to screen for highly expressing lines, and to detect strains within a mutagenized population with desirable characteristics.

Ref.: Crozet P, et al (2018) Birth of a Photosynthetic Chassis: A MoClo Toolkit Enabling Synthetic Biology in the Microalga Chlamydomonas reinhardtii. ACS Synth Biol 7: 2074–2086