Biodegradation of petroleum oil using a constructed nonpathogenic and heavy metal-tolerant bacterial consortium isolated from marine sponges

Abstract

Marine sponges are an attractive source of bacterial strains that are tolerant to and able to degrade toxic compounds. This study reveals the diverse bacterial communities of marine sponges collected from the Thailand coast by using 16S rRNA gene amplicon sequencing. Functional predictions using Tax4Fun2 indicated that the sponge bacterial communities have the potential for crude oil degradation. In this work, two nonpathogenic crude oil-degrading bacteria, Sphingobium naphthae MO2–4 and Bacillus aryabhattai TL01–2, isolated from the sponges Chalinula sp. and Clathria reinwardti, respectively, were selected to construct a bacterial consortium named MOTL. The results showed that the strains MO2–4 and TL01–2 had biosurfactant producing abilities and each had the ability to adhere to hydrocarbons. These strains also demonstrated capacities for surviving in the presence of various heavy metals. Moreover, strain MO2–4 contained genes encoding hydrocarbon-degrading enzymes. Consortium MOTL achieved 64%, 63%, and 51% degradation efficiencies for 2000 mg L−1 crude oil, diesel oil, and fuel oil, respectively, within 7 days and still maintained its degradation capacity when the concentration of petroleum oil increased to 8000 mg L−1. The consortium could degrade phenanthrene, tetradecane and a mixture of phenanthrene and tetradecane, and its degradation efficiencies were more effective than those of the individual strains. Consequently, the consortium MOTL is a promising candidate for the full-scale application of petroleum bioremediation in the presence of heavy metals.