LAUSR

Two pyrene-degrading strains, Pseudomonas aeruginosa PA06 and Achromobacter sp. AC15 were co-incubated in equal proportions as a microbiological consortium and could enhance the degradation of pyrene. The enzymatic activities of the catechol 1,2-dioxygenase (C12O) and 2,3-dioxygenase activities (C23O) were produced complementary expression by P. aeruginosa PA06 and Achromobacter sp. AC15, respectively. Meanwhile, results showed that pyrene degradation was sufficiently promoted in the presence of sodium citrate as a co-metabolic carbon source, likely a result of enhanced biomass and biosurfactant production. The optimized dosage and ideal initial pHs were 1.4 g L −1 and 5.5, respectively. We also analyzed the rate constant of pyrene degradation, cell growth, and enzyme activity. Results show that P. aeruginosa PA06 had a better effect than Achromobacter sp. AC15 in bacterial growth. However, the C23O or C12O activity produced by Achromobacter sp. AC15 continued at a similar or even faster than that of P. aeruginosa PA06. The mixed bacteria had a better effect than any single bacteria, suggesting the strains worked synergistically to enhance the degradation efficiency. In the co-metabolism system of 600 mg/L pyrene and 1.4 g/L sodium citrate, pyrene degradation reached 74.6%, was 1.57 times, 2.06 times, and 3.89 times that of the mix-culture strains, single PA06 and single AC15 without sodium citrate, respectively. Overall, these findings are valuable as a potential tool for the bioremediation of high-molecular-weight PAHs.