Bioprocessing of reduced sulfur compounds enhanced by treated wastewater with an alkaliphilic sulfur-oxidizing microbial consortium

An alkaliphilic sulfur-oxidizing bacterial consortium enrichment in synthetic media and supplemented treated wastewater was evaluated by measuring for thiosulfate biological oxidation and detailed analysis of the structure and function of the resultant bacterial communities. Aerobic batch assays revealed that cultures enriched with treated wastewater exhibited thiosulfate oxidation rates 17% faster than cultures in synthetic medium, attributed to the influence of inorganic and organic compounds present in the wastewater. Furthermore, cultures with treated wastewater demonstrated a 55% higher sulfate production rate than cultures with synthetic medium, probably due to specific intermediates generated during the oxidation process. 16S rRNA gene sequencing revealed greater microbial diversity in cultures with treated wastewater compared to cultures in synthetic medium, with Thioalkalivibrio prevailing as the dominant genus in both. Other genera, such as Planktosalinus, Aliidiomarina, Roseinatronobacter, and Azoarcus, were also identified; however, their relative abundances were associated with the available carbon sources in each medium. Functional analysis revealed a predominance of genes associated with thiosulfate and sulfide oxidation, emphasizing the significant role of the SOX system within cultures. The findings suggest the potential of treated wastewater to enrich an alkaliphilic sulfur-oxidizing bacterial consortia for biotechnological treatment of reduced sulfur compounds.