Ludmila Balan, Nina Bogdan-Golubi
The conservation of microorganisms of biotechnological interest is a fundamental component of scientific progress and sustainable economic development. Pigmented yeasts belonging to the genus Rhodotorula represent a source of valuable carotenoid pigments. Strain stability and the maintenance of biosynthetic capacity during preservation are critical aspects for the development of reproducible industrial processes. To ensure a higher viability of Rhodotorula strains after long-term storage, it is necessary to identify the most effective biopreparations for use in protective and/or rehydration media. To optimize the biotechnological production of carotenoids, strains R. gracilis CNMN-YS-03 and R. glutinis CNMN-YS-08 were reactivated using different mannoprotein extracts from beer and wine production processes. The reactivation of Rhodotorula using mannoproteic extracts in the rehydration medium results in a significant increase in biomass productivity (by 10–40%) and in biosynthetic activity. These effects depend on the type and concentration of the extract used, as well as the characteristics of the analyzed strain. Under these conditions, carotenoid biosynthesis can increase by up to 45%. Furthermore, the carbohydrate content, particularly in biomass of the Rhodotorula gracilis CNMN-YS-03 strain, increased by 37.5%, and the protein content in biomass of the Rhodotorula glutinis CNMN-YS-08 strain increased by 29.4% compared to the control sample.