Abstract:
Oil-spill bioremediation is an eco-friendly and sustainable approach towards the environment. This study aims to examine the synergistic interactions of bacterial consortium in crude oil and polycyclic aromatic hydrocarbons (PAHs) degradation and to develop an immobilized bacterial consortium as a ready-to-use bioproduct. The consortium OPK containing Mycolicibacterium strains PO1 and PO2, Novosphingobium pentaromativorans PY1 and Bacillus subtilis FW1, exhibited synergistic interaction in the biodegradation of pyrene, a mixture of PAHs, short- and long-chain alkanes, and crude oil. It maintained high degradation capacity degradation over a wide range of pH values (5.09.0), temperatures (3040°C), and salinities (2060‰). The whole genome sequencing results of our previous study combined with the degradation performance, biosurfactant producing ability and/or transcriptome analysis indicated that Mycolicibacterium plays an important role in the PAH and crude oil degradation. NidAB was the major enzyme involved in the degradation of pyrene and fluoranthene mixture which are the representative of high molecular weight (HMW) PAHs. Moreover, ribosomal proteins, an iron transporter, ABC transporters and stress response proteins may play a role in the survival of strains PO1 and PO2 under stress conditions. Furthermore, Novosphingobium strain contributed to intermediate degradation and Bacillus produced a biosurfactant that facilitates the assimilation of pollutants by the main degraders. In addition, the alkB and CYP153 genes involved in alkane degradation were detected in the genome of OPK members. Zeolite-immobilized OPK was developed as a ready-to-use bioproduct for the bioremediation of crude oil-contaminated environment. The results showed that the immobilized OPK removed 74% of 1000 mg L−1 crude oil within 96 h in sterilized seawater and could be reused for at least 5 cycles. Bioaugmentation using immobilized OPK in sandy soil microcosms significantly increased crude oil (10,000 mg kg−1 soil) removal from 45% to 80.67% within 21 days and stimulated an increase in the relative abundances of Alcanivorax, indigenous hydrocarbon-degrading bacteria, which in turn enhanced crude oil removal from soil. This finding provides ideal bio-based product for bioremediation of crude oil-polluted environments.