2023 Undergraduate Research Showcase

Document Type

Student Presentation

Presentation Date


Faculty Sponsor

Dr. Leonora Bittleston


Microbial communities are an essential part of every ecosystem, with bacteria within these microbial communities playing a crucial role in nutrient cycling. But research is lacking concerning how different microbial taxa vary in growth rate and enzyme production. By beginning to understand these microbial processes we can further develop our understanding of nutrient cycling within ecosystems, and how they promote environmental stability. We turned to Sarracenia purpurea (purple pitcher plant) as a model system for community ecology. The microbial communities within the plants can grow in a naturally enclosed and initially sterile environment, where then their growth can be monitored. By looking at the trends in microbial growth rates in a controlled laboratory environment, we can improve our knowledge of what tradeoffs might exist and how microbes may influence pitcher plant success. Our study asked: Is there a relationship between microbial growth rate and taxonomy or enzyme activity?

To explore this question, we looked at 34 bacterial strains collected from purple pitcher plants with known taxonomy. By growing them from frozen cultures in R2A media we measured the bacterial density of each strain (in triplicate) over 48 hrs at 590 nm. We compiled the growth curve data with our previously collected enzyme and taxonomy data and processed our analysis in R. From this analysis, we concluded that there were no significant differences in growth rates between different genera, families, or orders when the 34 bacterial isolates were clustered by taxonomy. There were also no significant differences in mean growth rate with protease, chitotriosidase, and endochitinase activity. But we did see some weak net negative directional effects in the probability densities for lipase and β-N-acetylglucosaminidase activity based on our model, which may indicate a potential tradeoff with the growth rate for the bacteria.