The Effect of Pseudomonas fluorescens and Bacillus subtilis on the Biodegradation of Low-Density Polyethylene
School Name
Spring Valley High School
Grade Level
10th Grade
Presentation Topic
Environmental Science
Presentation Type
Non-Mentored
Abstract
Low-density polyethylene (LDPE) poses many ecological and health risks due to being one of the most durable plastics to degrade. The objective of this study was to determine whether a co-culture of Pseudomonas fluorescens and Bacillus subtilis could degrade LDPE more effectively compared to its monoculture counterpart. It was hypothesized that the co-culture would biodegrade LDPE more than its monoculture or uninoculated control. Based on existing literature, both B. subtilis and P. fluorescens have been shown to degrade LDPE and that microbial co-cultures degrading plastics are more effective compared to individual bacterial efforts. LDPE plastic sheets were cut into squares, cleaned, and divided into four treatments, each replicated 30 times. LDPE squares were massed as a group rather than individually. Either P. fluorescens or B. subtilis was transferred from the stock culture into LB broth in test tubes. For co-culture preparation, one colony of each bacteria species was mixed and then transferred into test tubes. LDPE squares were placed into the inoculated test tubes and incubated at 30 °C for three weeks. Control tubes contained LB broth without inoculation. The hypothesis was not supported as the P. fluorescens monoculture produced the greatest mass loss (0.47%), followed by the co-culture (0.46%), while B. subtilis monoculture produced the least (0.24%). The control exhibited 0% mass loss. The co-culture showed less improvement compared to monocultures, indicating that P. fluorescens and B. subtilis, alone or combined, showed limited ability to degrade LDPE over a three week incubation period.
Recommended Citation
Zhou, Jessica, "The Effect of Pseudomonas fluorescens and Bacillus subtilis on the Biodegradation of Low-Density Polyethylene" (2026). South Carolina Junior Academy of Science. 86.
https://scholarexchange.furman.edu/scjas/2026/all/86
Location
Furman Hall 209
Start Date
3-28-2026 11:30 AM
Presentation Format
Oral and Written
Group Project
No
The Effect of Pseudomonas fluorescens and Bacillus subtilis on the Biodegradation of Low-Density Polyethylene
Furman Hall 209
Low-density polyethylene (LDPE) poses many ecological and health risks due to being one of the most durable plastics to degrade. The objective of this study was to determine whether a co-culture of Pseudomonas fluorescens and Bacillus subtilis could degrade LDPE more effectively compared to its monoculture counterpart. It was hypothesized that the co-culture would biodegrade LDPE more than its monoculture or uninoculated control. Based on existing literature, both B. subtilis and P. fluorescens have been shown to degrade LDPE and that microbial co-cultures degrading plastics are more effective compared to individual bacterial efforts. LDPE plastic sheets were cut into squares, cleaned, and divided into four treatments, each replicated 30 times. LDPE squares were massed as a group rather than individually. Either P. fluorescens or B. subtilis was transferred from the stock culture into LB broth in test tubes. For co-culture preparation, one colony of each bacteria species was mixed and then transferred into test tubes. LDPE squares were placed into the inoculated test tubes and incubated at 30 °C for three weeks. Control tubes contained LB broth without inoculation. The hypothesis was not supported as the P. fluorescens monoculture produced the greatest mass loss (0.47%), followed by the co-culture (0.46%), while B. subtilis monoculture produced the least (0.24%). The control exhibited 0% mass loss. The co-culture showed less improvement compared to monocultures, indicating that P. fluorescens and B. subtilis, alone or combined, showed limited ability to degrade LDPE over a three week incubation period.
