The Potential of Indigenous Bacteria from Various Soil Samples in Degrading Polymer Plastic Waste

The accumulation of plastic waste is a significant global issue encountered by many countries. Due
to its resistance to natural degradation, plastic waste eventually finds its way into the soil, leading to
alterations in soil composition. Plastic, a complex polymer with diverse applications, has become
integral to various aspects of life. Correspondingly, the extensive use of High-Density Polyethylene
(HDPE) and Low-Density Polyethylene (LDPE) plastics has escalated waste production. Hence, this
research aimed to isolate indigenous bacteria from diverse soil samples obtained from Surabaya's
landfill area and mangrove forests, specifically focusing on their capability to degrade HDPE and
LDPE plastic polymers. Sampling was conducted at the Keputih bamboo forest in Surabaya and the
Final Disposal Site (TPA). Bacteria were subsequently separated from the plastic waste and soil
samples. Afterward, the isolated bacteria were purified and screened for their ability to degrade
LDPE and HDPE polymers. The isolation process yielded 19 isolates, predominantly bacilli, Gramnegative, and catalase-positive bacteria capable of fermenting lactose and glucose, with cell sizes
ranging from 1 to 5 µm. Screening tests revealed that Isolate 17 (K2D3U1 MWJ), originating from the
Wonorejo mangrove forest, was identified as Pseudomonas sp. with an LDPE degradation ability of
21.64%. On the other hand, Isolate 2 (K1D2U2 KPH), obtained from the Keputih Final Disposal Site
(TPA), was identified as Bacillus sp. with an HDPE degradation ability of 27.13%.