Objective Biodesulfurization is a green purification technology that utilizes aerobic and anaerobic bacteria to remove sulfur-containing compounds at ambient temperature. It has the advantages such as high desulfurization efficiency, simple equipment requirements, short construction time, low cost and less chemical consumption. However, key challenges remain to be addressed, including the insufficient understanding of desulfurization mechanisms, inability to rapidly ascertain the optimal operational conditions for desulfurizing microorganisms, and low salinity tolerance of desulfurization bacteria.

Method A sulfide-oxidizing bacterial strain TYYJ-1 was isolated from the wastewater treatment pool of a natural gas purification plant of PetroChina Southwest Oil & Gasfield Company. Through the comparative analysis of 16S rRNA gene, the strain TYYJ-1 belongs to Aneurinibacillus aneurinilyticus. After investigating the morphology and growth characteristics of TYYJ-1, its biodesulfurization performance was systematically examined through single-factor experiments and Box-Behnken response surface optimization experiments. The whole-genome sequencing was performed using a combination of PacBio RS Ⅱ single molecule real-time sequencing and Illumina next-generation sequencing, and the genome completion map was constructed.

Result When the culture temperature was 33 ℃, the culture time was 45 h and the initial pH was 7.3, the highest S²⁻ oxidation rate reached 97.4%. The strain TYYJ-1 had strong salt tolerance, and grew under the condition of Na₂SO₄ mass concentration of 25 g/L and exerted a stable desulfurization effect. After analyzing the basic properties of the TYYJ-1 genome, the functional genes were annotated with molecular biology databases such as clusters of orthologous groups（COG）, Kyoto encyclopedia of genes and genomes（KEGG）, and gene ontology（GO）, and the desulfurization mechanism and salt tolerance mechanism of TYYJ-1 were explored from the genetic level. The results showed that strain TYYJ-1 could oxidize sulfides through metabolic pathways such as sqr, and assimilate sulfides through genes such as cysK and metY to synthesize sulfur-containing amino acids required for its growth and metabolism. At the same time, TYYJ-1 expressed TST protein to decompose thiosulfate generated during biodesulfurization. The strain TYYJ-1 could express trkH protein and enhance osmotic pressure tolerance and salt tolerance by accumulating K⁺.

Conclusion The strain has the characteristics of strong sulfur oxidation ability, high salinity resistance and removal of various sulfides, and has broad application potential in the field of biodesulfurization.