Isolation of sulfide remover strain Thermithiobacillus tepidarius JNU-2, and scale-up bioreaction for sulfur regeneration

Abstract

A sulfur removing bacterium named JNU-2 was isolated from an industrial anaerobic sludge pool. Its 16S rRNA phylogeny showed high homology to the species Thermithiobacillus tepidarius. The strain Thermithiobacillus tepidarius JNU-2 was initially cultivated for removing sulfide from sulfate-containing waste water for recycling sulfur. Thiosulfate removal and elemental sulfur production ratios reached 98.0 % and 83.06 %, respectively, after incubating for 24 h. Furthermore, based on the traits of JNU-2, a novel sulfur regeneration reactor—an internal airlift loop reactor (IALR)—was constructed and applied successfully. The key operating conditions of ventilatory capacity (VC) and hydraulic retention time (HRT) were also investigated. The production ratio of elemental sulfur was about 60.0 % and the maximal yield was 75 mg L−1 h−1 at 60 mL min−1 VC and 10 h HRT. All results indicated that the strain JNU-2 and the novel reactor would be of great potential for producing sulfur sources at industrial sites.