Evaluation of red-colored carotenoids in yeasts by the biomass color.

Production of carotenoids with red yeasts is a promising area of industrial biotechnology. All spectrophotometrical ("classic") analyses of carotenoids are based on preliminary extraction of the water-insoluble carotenoids; thus, these analyses are precise but complicated and time consuming. This paper presents a simple method to evaluate the red-colored carotenoids in yeast biomass by its color, without extraction. The method is based on digital characteristics of the biomass whole coloring, and it has already been successfully applied in other areas of biology: to compare plant and animal objects. In contrast to spectrophotometry measuring the amount of light that can pass through a solution, the biomass photo is a reflected color of the insoluble compounds. Application of this method to microorganisms permitted to compare the yeast strains and the effects of substrates or culturing regimes for any change in the red-colored pigments. The proposed rapid method was compared with the classic analyses of the carotenoids and showed that evaluation of red-colored carotenoids by the whole coloring of biomass can be used to discover changes in the yeast carotenoid production. In whole, the paper contributes method which is new for pigmented microorganisms and has a potential application in biotechnology.