Methods for transforming phaffia strains, transformed phaffia strains so obtained and recombinant dna in said methods

The present invention provides recombinant DNA comprising a transcription promoter and a downstream sequence to be expressed, in operable linkage therewith, wherein the transcription promoter comprises a region found upstream of the open reading frame of a highly expressed Phaffia gene, preferably a glycolytic pathway gene, more preferably the gene coding for Glyceraldehyde-3-Phosphate Dehydrogenase. Further preferred recombinant DNAs according to the invention contain promoters of ribosomal protein encoding genes, more preferably wherein the transcription promoter comprises a region found upstream of the open reading frame encoding a protein as represented by one of the amino acid sequences depicted in any one of SEQIDNOs: 24 to 50. According to a further aspect of the invention an isolated DNA sequence coding for an enzyme involved in the carotenoid biosynthetic pathway of Phaffia rhodozyma is provided, preferably wherein said enzyme has an activity selected from isopentenyl pyrophosphate isomerase activity, geranylgeranyl pyrophosphate synthase activity, phytoene synthase activity, phytoene desaturase activity and lycopene cyclase activity, still more preferably those coding for an enzyme having an amino acid sequence selected from the one represented by SEQIDNO: 13, SEQIDNO: 15, SEQIDNO: 17, SEQIDNO: 19, SEQ ID NO: 21 or SEQIDNO: 23. Further embodiments concern vectors, transformed host organisms, methods for making proteins and/or carotenoids, such as astaxanthin, and methods for isolating highly expressed promoters from Phaffia .