The present invention provides genetically engineered microbial strains, in particular genetically engineered yeast strains, that produce at least 0.5 mg per g CDW of a sphingoid base according to Formula I or a salt or ester thereof. The present invention provides a method to obtain genetically engineered microbial strains producing at least 0.5 mg per g CDW of a sphingoid base according to Formula I or a salt or ester thereof. The method comprises the steps of: a) increasing the expression of a polynucleotide encoding an enzyme having ceramide synthase activity and/or an enzyme having ceramidase activity, the latter being capable of preferentially, or even specifically, hydrolyzing ceramides containing a sphingoid base according to Formula I, and/or b) decreasing the expression of a polynucleotide encoding an enzyme having sphingolipid Δ8-desaturase activity and/or an enzyme having ceramidase activity, the latter being capable of preferentially, or even specifically, hydrolyzing ceramides containing phytosphingosine or dihydrosphingosine as sphingoid base, and isolating strains with the required productivity.