Potensi Bakteri Sedimen Kawasan Hutan Mangrove Belawan dalam Mendegradasi Plastik Jenis Low Density Polyethylene (LDPE)

Abstract

The accumulation of non-biodegradable plastic waste has led to significant environmental concerns, particularly in the mangrove forest of Belawan, North Sumatra. The objective of this study is to ascertain the biodegradation potential of bacteria isolated from mangrove sediments in the area. Bacteria were isolated from three distinct sediment areas in the Belawan mangrove forest and the bacteria obtained were selected based on their ability to grow on mineral media containing 0.5% plastic powder. The biodegradation potential of low-density polyethylene (LDPE) plastic by bacteria was assessed in liquid media by quantifying the weight reduction of plastic sheets. The bacterial growth on the media and plastic sheets was analyzed and changes in the surface morphology of the plastic sheet were observed using a Scanning Electron Microscope (SEM). The molecular identification of the selected isolates was performed using primers 27F and 1492R to determine the bacterial species. Bacteria were isolated from Belawan mangrove sediments yielding 24 isolates with varying colony morphologies. Four of these isolates namely ES3, ES4, ES5 and ES7 exhibited the capacity to proliferate in a medium containing plastic powder. Biodegradation tests indicated that two isolates namely ES3 and ES7 could reduce the weight of LDPE sheets by approximately 50% during the 60-days incubation period. Observations of the plastic surface treated with bacteria revealed the presence of adherent colonies and significant changes to the plastic surface, including the formation of cracks and holes, indicating active degradation by bacteria. The molecular identification indicated that isolate ES3 belongs to the species Aeromonas caviae strain ACDMC1235, while isolate ES7 belongs to Enterobacter hormaechei subsp. xiangfangensis strain HZ12d. The study found two bacteria in the Belawan mangrove forest sediment that can degrade LDPE. The isolates obtained have the potential to be further researched and developed for their ability to degrade other types of plastic.