Date of Publication
4-2025
Document Type
Bachelor's Thesis
Degree Name
Bachelor of Science in Biology major in Medical Biology
Subject Categories
Microbiology
College
College of Science
Department/Unit
Biology
Thesis Advisor
Yokimiko D. Torrejos
Defense Panel Chair
Mark Christian Felipe R. Redillas
Defense Panel Member
Christian Jordan O. dela Rosa
Kris Lord T. Santos
Abstract/Summary
Plastic pollution endangers ecosystems and human health globally, with High-density polyethylene (HDPE) as a major contributor. This study investigated the biodegradation using microorganisms of HDPE through a microbial process. Through a comprehensive literature review, Micrococcus luteus and Proteus vulgaris were identified as potential HDPE-degrading species and were selected for evaluation. Both strains exhibited growth using HDPE as the sole carbon source. By day 4, M. luteus achieved a cell density of 6.0 x 108 cells while P. vulgaris reached approximately 9.0 x 108 cells, indicating potential plastic degradation capacity. Results showed that P. vulgaris had the highest average weight loss at 3.33 ± 2.89, while M. luteus had an average of 1.38% ± 6.04. The consortium consisting of M. luteus and P. vulgaris exhibited lower weight loss averages, suggesting that degradation is more effective in individual cultures. However, the differences in the plastic degradation experiment were found statistically insignificant. A Scanning Electron Microscopy (SEM) analysis revealed that the surfaces of M. luteus and P. vulgaris showed unevenness, and pits, in contrast to the negative control. P. vulgaris possesses enzymes involved in plastic degradation such as catalase-peroxidase and lipase, while M. luteus possesses laccase. Both species degraded HDPE, with P. vulgaris having relatively higher efficiency in both carbon utilization and weight reduction. Future research should optimize growth conditions to enhance bacterial and enzymatic activity.
Keywords: high-density polyethylene (HDPE), Micrococcus luteus, Proteus vulgaris, biodegradation, microbial consortium
Abstract Format
html
Language
English
Format
Electronic
Keywords
High-density polyethylene; Micrococcus luteus; Proteus vulgaris; Biodegradation; Microbial ecology
Recommended Citation
Malhabour, C. D., & Lunar, D. B. (2025). Harnessing microbial potential: The role of micrococcus luteus and proteus vulgaris in high-density polyethylene degradation. Retrieved from https://animorepository.dlsu.edu.ph/etdb_bio/101
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Embargo Period
4-13-2026
