Carotenoid ketolase genes and gene products, production of ketocarotenoids and methods of modifying carotenoids using the genes

A method of producing a ketocarotenoid in a host cell, the method comprising

• inserting into the host cell a vector comprising a heterologous nucleic acid sequence which encodes for a protein having ketolase enzyme activity and has a sequence which encodes the amino acid sequence of SEQ ID NO:
• 2 or 4, wherein the heterologous nucleic acid sequence is operably linked to a promoter;
• and
• expressing the heterologous nucleic acid sequence, thereby producing the ketocarotenoid.

A method of modifying the production of carotenoids in a host cell, relative to an untransformed host cell, the method comprising

• inserting into a host cell which already produces carotenoids a vector comprising a heterologous nucleic acid sequence which encodes for a protein having ketolase enzyme activity and has the nucleic acid sequence of SEQ ID NO:
• 1 or 3, wherein the heterologous nucleic acid sequence is operably linked to a promoter;
• and
• expressing the heterologous nucleic acid sequence in the host cell to modify the production of the carotenoids in the host cell, relative to an untransformed host cell.

A method of modifying the production of carotenoids in a host cell, relative to an untransformed host cell, the method comprising

• inserting into a host cell which already produces carotenoids a vector comprising a heterologous nucleic acid sequence which encodes for a protein having ketolase enzyme activity and has a sequence which encodes the amino acid sequence of SEQ ID NO:
• 2 or 4, wherein the heterologous nucleic acid sequence is operably linked to a promoter;
• and
• expressing the heterologous nucleic acid sequence in the host cell to modify the production of the carotenoids in the host cell, relative to an untransformed host cell.