Biodegradation efficacy of soil inherent novel sp. Bacillus tropicus (MK318648) onto low density polyethylene matrix

Abstract

The biodegradation of low density polyethylene (LDPE) was studied by employing a microbial strain isolated from the dumping site soil. The bacterium strain was identified as Bacillus tropicus (Gen Bank Accession no: MK318648) by 16S rRNA sequencing. The growth of the strain was observed on virgin LDPE during the biodegradation process. The change in properties of LDPE films before and after bacterial strain incubation was observed by FTIR, SEM, AFM, contact angle, mechanical and optical testing. Loss in mechanical properties and changes in optical properties of the polymer matrix was observed. Weight reduction by 10.15% and fall in the value of tensile strength, elongation at break, tear strength, Young’s Modulus, hardness and stiffness to 8.59 MPa, 10.85 mm, 69.18 N, 272.36, 37.6 Shor D and 10,672.21 N/m respectively were observed after 40 days of incubation. The transparency and haze percentage were also changed to 93.7% and 18.6% respectively after the study period. The pH of the media was measured during incubation to evaluate the change due to formation of different extracellular and intracellular enzymes excreted by the strain. Hence, Bacillus tropicus could be an efficient microorganism to degrade 10-micron thickness LDPE films, thereby preventing its harmful impacts in the environment.