Multisystem combined uranium resistance mechanisms and bioremediation potential of Stenotrophomonas bentonitica BII-R7: Transcriptomics and microscopic study

• Published in: Journal of hazardous materials 2021-02, Vol.403, p.123858-123858, Article 123858
• Main Authors: Pinel-Cabello, M., Jroundi, F., López-Fernández, M., Geffers, R., Jarek, M., Jauregui, R., Link, A., Vílchez-Vargas, R., Merroun, M.L.
• Format: Article
• Language: English
• Subjects: Biodegradation, Environmental; biomineralization; biosorption; microbial remediation; RNA-Seq; Stenotrophomonas; Transcriptome; Uranium - toxicity; uranium tolerance
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2020.123858

[Display omitted] •Stenotrophomonas bentonitica showed high U removal potential up to 96%.•Membrane proteins, transporters and phosphatase were up-regulated gene expressions.•Cell surface and extracellular U-phosphate mineral formation were observed.•Resistance of BII-R7 to U(VI) is mediated by a multisystem combined process. The potential use of microorganisms in the bioremediation of U pollution has been extensively described. However, a lack of knowledge on molecular resistance mechanisms has become a challenge for the use of these technologies. We reported on the transcriptomic and microscopic response of Stenotrophomonas bentonitica BII-R7 exposed to 100 and 250 μM of U. Results showed that exposure to 100 μM displayed up-regulation of 185 and 148 genes during the lag and exponential phases, respectively, whereas 143 and 194 were down-regulated, out of 3786 genes (>1.5-fold change). Exposure to 250 μM of U showed up-regulation of 68 genes and down-regulation of 290 during the lag phase. Genes involved in cell wall and membrane protein synthesis, efflux systems and phosphatases were up-regulated under all conditions tested. Microscopic observations evidenced the formation of U-phosphate minerals at membrane and extracellular levels. Thus, a biphasic process is likely to occur: the increased cell wall would promote the biosorption of U to the cell surface and its precipitation as U-phosphate minerals enhanced by phosphatases. Transport systems would prevent U accumulation in the cytoplasm. These findings contribute to an understanding of how microbes cope with U toxicity, thus allowing for the development of efficient bioremediation strategies.