Development of a basal media for carbon utilization assay and analysis of the starch utilization locus in Prevotella melaninogenica

Prevotella melaninogenica is a highly abundant member of the human respiratory microbiota, occupying a range of distinct niches from the oral cavity to the lower airways. Colonization within these nutrient diverse environments suggest a sophisticated metabolic system equipped to deal with large fluctuations in nutrient availability. However, the core physiology and metabolic profile of this bacteria remain largely uncharacterized. In this study, we developed a basal media conducive to assaying carbon utilization of P. melaninogenica and demonstrate the utilization of dietary carbohydrates with varied glycosidic bonds, including the starch mimic cyclodextrin. Furthermore, we identified the putative starch utilization system, highlighting the presence of three novel components which are absent from starch metabolism in the closely related Bacteroides genus. Together, these findings provide the first characterization of the nutritional profile and central metabolic capacity of P. melaninogenica, offering crucial insight into how this bacterium adapts to and thrives within ecologically distinct niches. IMPORTANCEThis work significantly advances our understanding of the metabolic capabilities of Prevotella melaninogenica, a common yet largely unexplored member of the respiratory microbiota. By mapping key aspects of its predicted starch utilization locus, we lay the foundation for future studies on microbial adaptation and persistence in the respiratory tract.