Degradation of multiple PAHs and co-contaminants by microbial consortia and their toxicity assessment

The anthropogenic activities toward meeting the energy requirements have resulted in an alarming rise in environmental pollution levels. Among pollutants, polycyclic aromatic hydrocarbons (PAHs) are the most predominant due to their persis-tent and toxic nature. Amidst the several pollutants depuration methods, bioremediation utilizing bio-degradation is the most viable alternative. This study investigated the biodegradation efficacy using devel -oped microbial consortium PBR-21 for 2-4 ringed PAHs named naphthalene (NAP), anthracene (ANT), fluorene (FLU), and pyrene (PYR). The removal effi-ciency was observed up to 100 +/- 0.0%, 70.26 +/- 4.2%, 64.23 +/- 2.3%, and 61.50 +/- 2.6%, respectively, for ini-tial concentrations of 400 mg L-1 for NAP, ANT, FLU, and PYR respectively. Degradation followed first-order kinetics with rate constants of 0.39 d(-1), 0.10 d(-1), 0.08 d(-1), and 0.07 d(-1) and half-life (t(1/2))of 1.8 h, 7.2 h, 8.5 h, and 10 h, respectively. The micro -bial consortia were found to be efficient towards the co-contaminants with 1 mM concentration. Toxicity examination indicated that microbial-treated PAHs resulted in lesser toxicity in aquatic crustaceans (Artemia salina) than untreated PAHs. Also, the study suggests that indigenous microbial consortia PBR-21 has the potential to be used in the bioremediation of PAH-contaminated environment.

Automated summary

This study investigated the biodegradation efficacy of polycyclic aromatic hydrocarbons (PAHs) using a developed microbial consortium, PBR-21. The results showed that PBR-21 was highly effective in removing PAHs at different concentrations and reducing their toxicity to aquatic crustaceans.