Spheroplasted cells: a game changer for DNA delivery to diatoms

Diatoms, vital to global carbon fixation and climate change mitigation, produce 20% of the world’s fixed organic carbon annually. Their potential as cell factories for biofuels, proteins, and other high value chemicals remains underutilized due to a lack of genetic engineering tools, with DNA delivery being the biggest challenge. Here, we present an optimized, highly efficient electroporation method for delivering DNA constructs as large as 55.6 kb toPhaeodactylum tricornutum, a model diatom species and emerging chassis for algal biotechnology. We also demonstrate that with this optimized protocol, episomes can be assembledde novo, forgoing the need for time-consuming traditional cloning steps inEscherichia coliandSaccharomyces cerevisiae. By incorporating other technologies, such as CRISPR genome editing, this method will accelerate diatom-based synthetic biology projects and, therefore, the development of sustainable technologies. This method should also be applicable to other diatom species.