The Effects of Glycerol on Biofilm Production


  • Nicholas Nedzesky Seneca Valley Senior High School
  • Abigail Matela, Ph.D. University of Pittsburgh School of Medicine
  • Thomas Lavelle Seneca Valley Senior High School
  • Brian Carson Seneca Valley Senior High School



Biofilms, Glycerol, Osmotic stress, Biofilm production, Pseudomonas fluorescens, Biofilm-producing bacteria, Membrane compression


Due to the widespread, antibiotic-resistant nature of biofilm-producing bacteria, there is high demand for research on biofilm formation.  This research serves as a contribution to the existing knowledge of how biofilms form.  Its results could shed light on how biofilm-producing bacteria utilize communication pathways in response to environmental and chemical stimuli.  To determine the effects of glycerol (a sugar alcohol linked to osmotic stress) on biofilm production, Pseudomonas fluorescens strain SBW25 was cultivated within a series of 5 culture tubes containing medias with increasing concentrations of glycerol from 0-10%.  After a week of incubation, a sample from each of the tubes was plated and colony morphology was qualitatively analyzed.  Each of the tubes was then stained with crystal violet and the absorbance of the biofilm could be quantitatively measured at 590nm with a dual-beam spectrophotometer.  The hypothesis is supported with the absorbance and plate data collected over the first and second trials of the experiment.  As glycerol concentration increased, the absorbance (and thus biofilm produced) increased proportionately, and the approximate number of wrinkly mutants on each successive plate increased.  The correlation of the data is significant enough to support the hypothesis, but more trials will need to be conducted in order to conclusively accept it. 


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Author Biographies

Nicholas Nedzesky, Seneca Valley Senior High School

Lab Manager in the Seneca Valley Center for Biotechnology Research 

Abigail Matela, Ph.D. , University of Pittsburgh School of Medicine

EvolvingSTEM Director of Educational Outreach and Research
Postdoctoral Scholar, Department of Microbiology and Molecular Genetics
University of Pittsburgh School of Medicine

Thomas Lavelle , Seneca Valley Senior High School

Director of the Seneca Valley Center for Biotechnology Research 

Brian Carson, Seneca Valley Senior High School

Director of the Seneca Valley Center for Biotechnology Research 

References or Bibliography

Armbruster, C. R., Lee, C. K., Parker-Gilham, J., de Anda, J., Xia, A., Zhao, K., Murakami, K., Shan Tseng, B., Hoffman, L. R., Jin, F., Harwood, C. S., Wong, G. C., & Parsek, M. R. (2019). Heterogeneity in Surface Sensing Suggests a Division of Labor in Pseudomonas aeruginosa Populations. eLife.

Baker, P., Hill, P. J., Snarr, B. D., Alnabelseya, N., Pestrak, M. J., Lee, M. J., Jennings, L. K., Tam, J., Melnyk, R. A., Parsek, M. R., Sheppard, D. C., Wozniak, D. J., & Howell, P. L. (2016). Exopolysaccharide Biosynthetic Glycoside Hydrolases Can Be Utilized to Disrupt and Prevent Pseudomonas aeruginosa Biofilms. Science Advances, 2(5).

Chen AI, Dolben EF, Okegbe C, Harty CE, Golub Y, et al. (2014) Candida albicans Ethanol Stimulates Pseudomonas aeruginosa WspR-Controlled Biofilm Formation as Part of a Cyclic Relationship Involving Phenazines. PLOS Pathogens 10(10): e1004480.

Ferreira, R., Ferreira, M., Glatthardt, T., Silvério, M. P., Chamon, R. C., Salgueiro, V. C., Guimarães, L. C., Alves, E. S., & Dos Santos, K. (2019). Osmotic Stress Induces Biofilm Production by Staphylococcus epidermidis Isolates from Neonates. Diagnostic microbiology and infectious disease, 94(4), 337–341.

Haas, D., & Keel, C. (2003). Regulation of Antibiotic Production in Root-Colonizing Pseudomonas spp. and Relevance for Biological Control of Plant Disease . Annual Reviews, 41(117-153).

Matela, A. (2020). EvolvingSTEM bioinformatics module. In A. Matela (Author), EvolvingSTEM bioinformatics module. EvolvingSTEM.

Pocivavsek, L., Gavrilov, K., Cao, K. D., Chi, E. Y., Li, D., Lin, B., Meron, M., Majewski, J., & Lee, K. Y. (2011). Glycerol-Induced Membrane Stiffening: the Role of Viscous Fluid Adlayers. Biophysical journal, 101(1), 118–127.

Suma C. Pemmaraju, Kumar Padmapriya, Parul A. Pruthi, R. Prasad & Vikas Pruthi (2016) Impact of Oxidative and Osmotic Stresses on Candida albicans Biofilm Formation, Biofouling, 32:8, 897-909,



How to Cite

Nedzesky, N., Matela , A., Lavelle , T. ., & Carson, B. (2021). The Effects of Glycerol on Biofilm Production . Journal of Student Research, 10(4).



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