Low-density polyethylene (LDPE) is an abundant and widely commercialized petroleum-based synthetic thermoplastic. It has a high molecular weight and a very hydrophobic surface. The strong C–C bond also makes LDPE resistant to biological attacks. Biodegradation presents a promising eco-friendly solution for tackling plastic waste. This study aimed to investigate the potential of yeast from plastic waste to degrade LDPE. Yeast was isolated from various plastic-polluted areas in Surabaya and Banyuwangi, Indonesia. The screening test was performed on mineral salt medium agar (MSMA) supplemented with polyethylene powder. The biodegradation test was conducted for 4 weeks in Mineral Salt Medium Broth (MSMB) with LDPE film. The ability of the isolates to degrade LDPE was evaluated by measuring the reduction in dry weight of plastic (% degradation), yeast growth via Optical Density (OD600 nm), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) analysis. Screening on MSMA showed that 13 isolates could degrade polyethylene, as indicated by the formation of clear zones. The five best isolates were used for further biodegradation tests. The yeast isolate M.3.0.1 exhibited the highest degradation percentage of 1.1474±0.0888%. It demonstrated increased growth in the test medium, as indicated by an increase in optical density. In addition, SEM analysis showed a change in the morphology of the LDPE surface, and FTIR analysis showed a change in the transmittance value for the test plastic.
Alami et al. (Thu,) studied this question.