The total economic value of microalgal biomass can be increased by redesigning the current single product value chain to a multipurpose value chain. A promising microalgae for the use in a multipurpose value chain is Chlorella, which produces several high-value compounds, such as the UV-absorbing mycosporine-like amino acids (MAAs) that can be valorised as photoprotective agents in sunscreens. In this project, an optimal Chlorella biomass with high MAA content will be created by selecting the optimal microalgae strain, culture system and metabolic engineering technique. First, candidate MAA-biosynthesis genes in Chlorella will be identified using comparative genomics. Simultaneously, a CRISPR/Cas toolbox to verify the candidate MAA-biosynthesis genes will be designed. Next, the confirmed MAA-biosynthesis genes will be upregulated by addition of a strong exogenous promotor to increase MAA production. In the final phase, I will grow the genetically engineered Chlorella and wild-type Chlorella on a large scale and evaluate different growth conditions for high MAA production and high biomass yield. In the end, I will have created Chlorella biomass with a high MAA content that could be implemented in a multipurpose value chain and a toolbox that can be used to increase the production of other high-value compounds in Chlorella.