Currently Kostya's two main areas of interest are the ecology of the gut microbiota and cancer cell metabolism. In both cases, he uses various mathematical methods for modeling a cell's interaction with the surrounding nutrient microenvironment and with neighboring cells as a part of a dynamic ecosystem. Kostya's overarching goal is to uncover the basic mathematical and biological principles that allow cells with diverse functional roles and requirements to persist in dynamically changing local microenvironments and to colonize novel microenvironments.