Abstract: A process for extracting carotenoids from a carotenoid-containing starting material produced by microorganisms is described. Said starting material is admixed with edible solvent to effectuate the transfer of carotenoids. Separation of the carotenoid-enriched edible solvent is improved by the formation of a “cake”, composed of said carotenoid-containing particulate solids, and, as required, a certain quantity of suitable filtration aid to modify the cake's consistency. Mechanical aids accelerate the separation of the carotenoid-enriched edible solvent. Said mixture may be hydrated to aid the removal of solids and gums from the carotenoid containing edible solvent. The carotenoid-enriched edible solvent is filtered though said cake to reduce the particulate load including any undesirable microbial load. A counter-current process increases the carotenoid concentration of the extract.

Abstract: A control method for operating aqueous Haematococcus spp., such as H. pluvialis, microorganism growth processes is disclosed which can maintain viable growth conditions of this microorganism which have heretofore not been easily reproduced in commercially valuable quantities. The primary control parameters are the degree of turbulence in the aqueous growth medium and the scale of the apparatus relative to the scale of the turbulent eddies in vessels which are partially filled with the aqueous medium directly affect conditions which are required for optimum growth: light exposure, nutrient supply, sedimentation rate, bulk temperature, gas exchange rate and cell integrity. These control elements can be cast in terms of the Reynolds number (N.sub.re), pH, temperature, amount of impinging light, and NO.sub.2 concentration, depending upon the operative chlorophyll growth stages of Haematococcus spp. and its photoadaptive stages of producing astaxanthin.

Abstract: A control method for operating aqueous microorganism growth processes is disclosed which can maintain viable growth conditions for many types of microorganisms which have heretofore not been easily reproduced in commercially valuable quantities. The primary control parameters are the degree of turbulence in the aqueous growth medium and the scale of the apparatus relative to the scale of the turbulent eddies in vessels which are partially filled with the aqueous medium directly affect conditions which are required for optimum growth: light exposure, nutrient supply, sedimentation rate, bulk temperature, gas exchange rate and cell integrity. These control elements can be cast in terms of the Reynolds number (N.sub.Re) and controlled dimensions of the apparatus (L.sub.K) in relationship to the scales of turbulent eddies to define the dissipation .lambda..sub.K as L.sub.K /L.