Microalgae represent a promising bioresource for the production of a variety of high-value metabolites including polyunsaturated fatty acids (PUFA’s), pigments, polysaccharides, proteins. Today, synthetic biology offers the opportunity to optimise the metabolic pathways to improve strain performance, such as enhanced photosynthetic capabilities, heterotrophic cultivation on cellulose feedstock or boosting high-value metabolite yields. Recent developments in CRISPR/Cas9 gene editing technologies represent a new era for the engineering of algal genomes. However, the royalties associated with this gene editing tool limit its applicability for SMEs. We are therefore planning to assess whether a newly developed and royalty-free nuclease, called MAD7, can be used in P. tricornutum. The MAD7-gRNA encoding genes will be inserted in the diatom using a new transformation method that offers promising opportunities to improve the performance of industrially relevant microalgae. The primary objective will be to use the MAD7 nuclease to knock-out the phosphoenolpyruvate carboxykinase (PPCase) enzyme. The resulting strains will be cultured under a range of organic carbon sources, in order to establish the effects of the deletion on the lipidomics of P. tricornutum under optimised cultivation strategy.