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.