Provided herein are recombinant cells (e.g., recombinant bacteria or plant, insect, mammalian, and yeast cells) containing a nucleic acid encoding a CYP97A protein or a nucleic acid encoding a CYP97B protein; a nucleic acid encoding a CYP97C protein; a nucleic acid encoding a geranylgeranyl pyrophosphate synthase protein; a nucleic acid encoding a phytoene synthase protein; a nucleic acid encoding a phytoene desaturase protein; a nucleic acid encoding a lycopene -cyclase protein; and a nucleic acid encoding a lycopene -cyclase protein. Also provided are methods of producing lutein that include culturing these recombinant cells (e.g., recombinant bacteria and yeast cells), and methods of generating these recombinant cells (e.g., recombinant bacteria and yeast cells). Also provided is lutein produced by these methods, and pharmaceutical compositions, food supplements, food products, and cosmetic compositions that contain lutein produced by these methods.

Provided herein are recombinant cells (e.g., recombinant bacteria or plant, insect, mammalian, and yeast cells) containing a nucleic acid encoding a CYP97A protein or a nucleic acid encoding a CYP97B protein; a nucleic acid encoding a CYP97C protein; a nucleic acid encoding a geranylgeranyl pyrophosphate synthase protein; a nucleic acid encoding a phytoene synthase protein; a nucleic acid encoding a phytoene desaturase protein; a nucleic acid encoding a lycopene -cyclase protein; and a nucleic acid encoding a lycopene -cyclase protein. Also provided are methods of producing lutein that include culturing these recombinant cells (e.g., recombinant bacteria and yeast cells), and methods of generating these recombinant cells (e.g., recombinant bacteria and yeast cells). Also provided is lutein produced by these methods, and pharmaceutical compositions, food supplements, food products, and cosmetic compositions that contain lutein produced by these methods.

The present invention relates to a process for purifying the xanthophylls astaxanthin and canthaxanthin. The process comprises suspending the xanthophyll in an organic solvent or solvent mixture, treating the suspension of the xanthophyll in the organic solvent or solvent mixture at elevated temperature, and subsequent separation off of the xanthophyll from the solvent by a solid-liquid separation, wherein the organic solvent is selected from ketones of the general formula (I) and mixtures of ketones of the general formula (I) ##STR00001##
where R.sup.1 is C.sub.1-C.sub.4 alkyl and R.sup.2 is selected from C.sub.1-C.sub.6 alkyl, C.sub.3-C.sub.8 cycloalkyl, phenyl and benzyl, wherein the phenyl rings in the two last-mentioned radicals are unsubstituted or can have 1 or 2 methyl groups, or R.sup.1 and R.sup.2 together are linear C.sub.4-C.sub.6 alkylene, which can bear 1, 2 or 3 methyl groups as substituents.

The present invention relates to a process for purifying the xanthophylls astaxanthin and canthaxanthin. The process comprises suspending the xanthophyll in an organic solvent or solvent mixture, treating the suspension of the xanthophyll in the organic solvent or solvent mixture at elevated temperature, and subsequent separation off of the xanthophyll from the solvent by a solid-liquid separation, wherein the organic solvent is selected from ketones of the general formula (I) and mixtures of ketones of the general formula (I) ##STR00001##
where R.sup.1 is C.sub.1-C.sub.4 alkyl and R.sup.2 is selected from C.sub.1-C.sub.6 alkyl, C.sub.3-C.sub.8 cycloalkyl, phenyl and benzyl, wherein the phenyl rings in the two last-mentioned radicals are unsubstituted or can have 1 or 2 methyl groups, or R.sup.1 and R.sup.2 together are linear C.sub.4-C.sub.6 alkylene, which can bear 1, 2 or 3 methyl groups as substituents.

The invention relates to a method for the non-stereoselective and also for the stereoselective synthesis of astaxanthin from astacin. For this purpose, a reducing agent is used selected from the group of hydrogen, a secondary alcohol, formic acid and also the salts of formic acid or from a mixture of at least two representatives of the compound classes stated above. The invention further relates to the use of astacin as starting compound for the synthesis of astaxanthin.

The invention relates to a method for the non-stereoselective and also for the stereoselective synthesis of astaxanthin from astacin. For this purpose, a reducing agent is used selected from the group of hydrogen, a secondary alcohol, formic acid and also the salts of formic acid or from a mixture of at least two representatives of the compound classes stated above. The invention further relates to the use of astacin as starting compound for the synthesis of astaxanthin.

The invention relates to a method for preparing a cyclic -ketoalcohol, particularly a 6-hydroxycyclohexenone from a cyclic -ketoenol, particularly a 6-hydroxycyclohexadienone, using a reducing agent. This reducing agent is selected from hydrogen gas; a secondary alcohol, formic acid and the salts of formic acid or a mixture of at least two representatives of these compound classes. The invention further comprises the use of an -ketoenol, in particular a 6-hydroxycyclohexadienone, as intermediate for preparing astaxanthin.

The invention relates to a method for preparing a cyclic -ketoalcohol, particularly a 6-hydroxycyclohexenone from a cyclic -ketoenol, particularly a 6-hydroxycyclohexadienone, using a reducing agent. This reducing agent is selected from hydrogen gas; a secondary alcohol, formic acid and the salts of formic acid or a mixture of at least two representatives of these compound classes. The invention further comprises the use of an -ketoenol, in particular a 6-hydroxycyclohexadienone, as intermediate for preparing astaxanthin.

The present invention discloses a method for preparing controlled release type lutein feed additive. Steps: lutein extract, glycerol and fat are mixed and dissolved, then alkali liquor is dropped under condition of mechanical stirring and sheering emulsification to allow the lutein to be fully saponified. Then fat is added and alkaline saponification is conducted, adjusting the viscosity and neutralizing and conducting spray granulation to the mixed liquor to obtain controlled release lutein feed additive. By utilizing the combined effects of glycerol and fat, the present invention realizes saponification and microcapsule formation using simple method. Comparing to conventional absorption processes, the present invention effectively improves the chemical stability of lutein in light, heating and acid environment, allowing the controlled release type lutein feed additive product to barely release in gastric fluid environment but fully release in intestinal fluid environment, hence achieving higher bioavailability.

The present invention discloses a method for preparing controlled release type lutein feed additive. Steps: lutein extract, glycerol and fat are mixed and dissolved, then alkali liquor is dropped under condition of mechanical stirring and sheering emulsification to allow the lutein to be fully saponified. Then fat is added and alkaline saponification is conducted, adjusting the viscosity and neutralizing and conducting spray granulation to the mixed liquor to obtain controlled release lutein feed additive. By utilizing the combined effects of glycerol and fat, the present invention realizes saponification and microcapsule formation using simple method. Comparing to conventional absorption processes, the present invention effectively improves the chemical stability of lutein in light, heating and acid environment, allowing the controlled release type lutein feed additive product to barely release in gastric fluid environment but fully release in intestinal fluid environment, hence achieving higher bioavailability.