Characterizing microbial diversity in plastic-contaminated soils: a molecular approach

Diversity of microorganisms in soil is critical for ecosystem functioning, nutrient circulation and plant health. In this study, a soil sample was collected from the plastic-contaminated environment, and DNA was purified. The 16S rRNA gene of the ssoil sample was amplified and the bacterial population was determined. Three major phyla, including Proteobacteria (24.3%), Firmicutes (15.92%) and Planctomycetota (11.37%), were abundant in the plastic-contaminated sample. The sequences were analyzed at the class level, and the identified bacteria belong to 15 classes. Among the 15 classes, Bacilli (15.5%), Gamma-proteobacteria (12.73%), Alpha-proteobacteria (11.56%) and Bacteroidia (9.51%) were dominated. Proteobacteria was the dominant phylum (24.3%), and 15.5% of the detected bacteria was from the class Bacilli. The soil sample was enriched with 12.22% of Bacillales, and 11.22% of bacteria were detected from the family Bacillaceae. The most abundant bacteria at the species level were Bacillus (9.46%), and unclassified bacteria also contributed a significant level (8.76%). The Shannon index was 10.09, and the Simpson index was 1. The larger Simpson reciprocal index value (767.7) of the plastic-contaminated sample revealed a high level of bacterial diversity. The results revealed the abundance of Bacillus species in the plastic-contaminated environment and may be useful managing the plastic-contaminated environment.