A plurality of isolated polynucleotide sequences encoding enzymes of the astaxanthin pathway is disclosed. The polynucleotides include: (i) a polynucleotide which encodes Phytoene dehydrogenase (crtI) and a first transcriptional regulatory sequence; (ii) a polynucleotide which encodes Beta-lycopene cyclase (lcy-B) and a second transcriptional regulatory sequence; (iii) a polynucleotide which encodes Beta-carotene ketolase (crtW) and a third transcriptional regulatory sequence; and wherein the first, second and third regulatory sequence are selected such that the expression of the Icy-B and the crtW is greater than a level of expression of the crtI. Methods of generating astaxanthin using the plurality of polynucleotide are also disclosed as well as bacterial cells comprising high levels of astaxanthin.