Abstract
Plastic waste accumulation has become a major environmental concern, particularly in landfill ecosystems where plastic surfaces serve as habitats for microbial communities known as the plastisphere. This study aimed to isolate and identify bacterial isolate associated with the plastisphere associated with plastic waste collected from the Sumompo Landfill, Manado City, Indonesia. Plastic bag (SPK) and plastic bottle (SPB) samples were processed using serial dilution and spread plate techniques on Nutrient Agar (NA), followed by bacterial purification and molecular identification based on 16S rRNA gene analysis. A pure bacterial isolate was successfully obtained only from the plastic bag sample, whereas the plastic bottle sample failed to yield a representative isolate due to contamination. PCR amplification produced a 16S rRNA gene fragment of approximately 1400–1500 bp. After sequence trimming, a 989 bp sequence showed 99.72% similarity to Bacillus cereus strain ATCC 14579 using BLAST analysis. Phylogenetic analysis with the Neighbor-Joining method confirmed its placement within the Bacillus cereus clade with 100% bootstrap support. These findings identify Bacillus cereus as a member of the plastisphere bacterium in the Sumompo Landfill and provide baseline data for future investigations of landfill plastisphere microbial diversity.