The Potential of Marine Yeast and Its Interaction with Mold in Degrading High-Density Polyethylene (HDPE)

Abstract

Indonesia is one of the countries that contributes significant amounts of plastic waste to coastal environments. High-density polyethylene (HDPE) is a petroleum-based synthetic thermoplastic and the primary source of environmental plastic pollution. The stable aliphatic chains with strong C–C bonds in HDPE render it recalcitrant to microbial degradation. Bioremediation through biodegradation by microorganisms can be an effective and environmentally friendly solution for eliminating HDPE from ecosystems. Several studies have suggested that microbial consortia may enhance plastic biodegradation. However, the effectiveness of marine yeast-mold interactions in HDPE degradation remains poorly understood. This study aimed to evaluate the potential of marine yeast to degrade HDPE and assess its effectiveness when combined with molds for HDPE degradation. The biodegradation experiment was conducted over 30 days using Mineral Salt Medium Broth (MSMB) and plastic sheets. The parameters assessed during biodegradation included degradation effectiveness (%), total count of heterotrophic microorganisms (CFU/mL), and Scanning Electron Microscope (SEM) analysis. The results show that marine yeast has the potential to be used alone or in combination with molds. The highest value was achieved by the P2 treatment group in week 4, which consisted of a consortium of marine yeast and mold, with a value of 4.855%. However, this was not significantly different from P1, which consisted of a consortium of marine yeast with a value of 4.17%. The SEM test results indicated biofilm formation in all treatments, suggesting plastic biodegradation activity.