Effectiveness of FBS-DMSO cryoprotectant composition in artificial microbiome models mimicking key gut microbiota...

The ratio of microorganisms in the composition of the microflora of the small and large intestines plays a crucial role in human health. Therefore, it is essential to preserve the original proportions of species over an extended period for their further therapeutic application. It has previously been established that three primary enterotypes dominate the human gut microbiota: Bacteroides, Prevotella, and Ruminococcus. However, there is no precise information on how their species ratios are affected by deep freezing. In our study, we examined the preservation of the ratios of microorganisms in the human gut before and after cryopreservation, represented as distinct clusters consisting of four different bacterial species dominant in the gut microbiome. Using photometric registration of optical density and fluorescent staining methods, we demonstrated that the viability of most bacteria remained high in the cryoprotective medium of 5 % Me₂SO/FBS. Additionally, the calculation of the Pattern Comparison Index (PCI) showed good results in maintaining the community structure of bacteria in each of the artificial models. Thus, this modeling of microbiocenoses allows for the identification of patterns in the preservation of their quantitative composition during long-term storage in liquid nitrogen.