Revealing sulfate role in empowering the sulfur-oxidizing capacity of Thioalkalivibrio versutus D301 for an enhanced desulfurization process

[Display omitted] •The thiosulfate oxidation capability of D301 was enhanced by sulfate supply.•Higher elemental sulfur production of D301 was triggered by sulfate.•Lower ROS and compatible solutes were accumulated in sulfate-grown cells.•The downregulation of central carbon metabolism was induced by sulfate.•Sulfate promoted the expression of hdrABC but inhibited that of sorA and soeABC. Haloalkaliphilic Thioalkalivibrio, a dominant genus for sulfide removal, has attracted growing interest. However, the bacterial biological response to this process’s final product, sulfate, has not been well-studied. Here, thiosulfate oxidation and sulfur formation by T. versutus D301 were being enhanced with increasing sulfate supply. With the addition of 0.73 M sulfate, the thiosulfate utilization rate and sulfur production were improved by 68.1% and 120.1% compared with carbonate-grown control at the same salinity (1.8 M). For sulfate-grown cells, based on metabolic analysis, the downregulation of central carbon metabolism indicated that sulfate triggered a decrease in energy conservation efficiency. Additionally, the gene expression analysis further revealed that sulfate induced the inhibition of sulfur to sulfate oxidation, causing the upregulation of thiosulfate to sulfur oxidation for providing cells with additional energy. This study enhances researchers’ understanding regarding the sulfate effect on the bio-desulfurization process and presents a new perspective of optimizing the biotechniques.