This article discusses environmentally safe and biotechnologically efficient methods for obtaining probiotic systems based on fermented bran. Microbiological fermentation processes enable the biochemical transformation of complex organic substrates and the formation of highly active probiotic consortia. During fermentation, the chemical composition of the substrate changes, the level of bioactive metabolites increases, and the enzymatic, antagonistic, and adaptive properties of lactic acid bacteria are enhanced. In addition, the mechanisms of action of the obtained probiotic systems on microbiota are considered, including the regulation of microbial balance and bio-protective effects. The results of the study demonstrate that such biotechnological products have high functional potential and may serve as a basis for the development of new directions in microbiological biotechnology. This approach enables the development of sustainable and efficient probiotic bio-systems.