Bismuth oxychloride microsphere-assisted construction of bacterial consortia for enhanced petroleum hydrocarbon degradation under high-salt stress

The biodegradation of petroleum hydrocarbons or other pollutants by microbial consortia under high salt-stress is significant for mitigating environmental pollution treatment. In this study, an artificial ternary consortium system composed of three halotolerant bacteria (Exiguobacterium mexicanum, Terribacillus saccharophilus and Staphylococcus warneri) isolated from oilfield reservoir was firstly constructed, which showed a complementary effect on petroleum hydrocarbon emulsification and degradation. Vacancy engineered bismuth oxychloride microspheres (BiOCls) were introduced. Density functional theory calculation (DFT) and polysaccharide adsorption assays revealed that microspheres of VBiO-type (BV1) exhibited a much higher capacity to adsorb extracellular polysaccharides than VBiOBiBiBi-type (BV2). Owing to the high adsorption capacity, BV1 strongly recruited three bacterial, making this system with much higher bacterial numbers than BV2. Besides, added BV1assisted consortium to the natural crude oil medium at high salt stress decreased the Simpson index and increased the abundance of the three bacteria, indicating that BV1 enhanced consortium sustainability. Consequently, BV1-assisted system degraded petroleum hydrocarbons at a much higher rate than control (84.6% versus 45.2%-51.2% under 6% NaCl, and 21.3% versus 1.3%-14.3% under 10% NaCl). This study provides a facile nanomaterial-based strategy to assist in the construction of functional consortia for environmental applications.