Efficiencies of Thermophilic Bacteria Species in Degrading Biodegradable Low-density Polyethylene Mixtures in Aquatic Ecosystems

Abstract

The study examined the efficiencies of bacteria thermophiles responsible for the depolymerization of biodegradable Low-Density Polyethylene (LDPE) blends in two aquatic environments to suggest model bacteria species that could be used for reducing the accumulation of single-use LDPE in both marine and freshwater ecosystems. Each of the biodegradable LDPE, polyethylene, and cellulose was placed in respirometry jars filled with 500 mls of the freshwater and marine water respectively in a randomized design of 4 by 2 by 3 following the American Standard Testing and Materials (ASTM) procedure. To identify the bacteria species, bacterial isolation was done using pour plate and streak methods. The bacteria species were identified by morphological, biochemical, and molecular methods. The thermophilic bacteria species were confirmed by sequencing to be Bacillus cereus, Pseudomonas species among others. The results revealed that the bacteria isolates on LDPE were responsible for the biodegradation processes of the LDPE. This study concluded that Bacillus cereus and Pseudomonas species have the bioremediation potentials to break down single-use biodegradable Low-Density Polyethylene (LDPE) in aquatic environments within six (6) months.