Isolation, characterization and optimization of bacterial isolate SARR1 for biodegradation of pretreated low density polyethylene

Abstract

Accumulation of low-density polyethylene (LDPE) has caused a threat to the environment because of its stable and inert nature as it cannot be degraded easily by microorganisms. Its lightweight, low cost, strength, durability, and its various other applications, have led to the wide usage of the polymer, which is exerting a negative effect on both marine and land biota. The development of an eco-friendly or a promising strategy is needed to reduce LDPE waste from both land and water. In the present study, observations have been made to isolate highly efficient LDPE degrading bacteria. The response surface methodology (RSM) was used to predict the best optimization of media for the degradation of LDPE by isolate SARR1. The isolate SARR1 was selected through primary screening by weight loss method and secondary screening using CO2 evolution test, TTC and MATH Test. The isolate SARR1 showed 6.30 ± 0.25 g/L CO2 evolution. The microbial adhesion hydrophobicity (MATH) was observed during log phase (100 to 56.89 ± 0.97 %) and stationary phase (100 to 82.92 ± 1.24 %). An isolate SARR1 converted the TTC into red coloured insoluble triphenyl formazan (TPF) after incubation of 7 days. The isolated bacteria SARR1 showed 38.3 ± 1.27 % biodegradation efficiency in the pretreated LDPE strips at 37 °C and pH 7.0 under optimized conditions within 30 days of incubation. This bioremediation and biodegradation approach is eco-friendly and safe for the environment. The results of treatment with isolate SARR1 had a potential hope to degrade LDPE at higher rate than natural degradation.