Green microalgae lacking a functional DYRKP-1 gene, for use for increased production of feedstock

A method for producing biomass feedstock, comprising the steps of:

• (i) cultivating green microalgae cells in which the expression and/or the activity of the dual-specificity tyrosine-phosphorylation-regulated kinase (DYRKP-1) protein is impaired in comparison to wild-type green microalgae cells,
• wherein the amino acid sequence of said DYRKP-1 protein is SEQ ID NO:
• 1, or a sequence having at least 90% sequence identity to SEQ ID NO:
• 1 and comprising the DH box sequence of SEQ ID NO:
• 3, and wherein said impairment is obtained by silencing, knocking down, mutating and/or interrupting the DYRKP-1 gene or by inhibiting the activity of the DYRKP-1 protein by a chemical compound acting as a specific inhibitor;
• and
• (ii) inducing an accumulation of a reserve compound and/or an increase in biomass production by said microalgae, in comparison to wild-type green microalgae cells, by incubating the microalgae cells in a deficient medium, wherein said deficient medium is deficient in at least one element, the concentration of said element being at least 10-fold below the concentration of said element in a classical medium used for microalgae medium;
• wherein the biomass produced is oil or starch.