Study on Haloalkaliphilic Sulfur-Oxidizing Bacterium for Thiosulfate Removal in Treatment of Sulfidic Spent Caustic

Abstract

Abstract. Due to the disadvantages of physiochemical methods for sulfidic spent caustic treatment, attentions are drawn to the environmental-friendly biotreatments including sulfur-oxidizing haloalkaliphiles. Thioalkalivibrio versutus DSM 13738 was grown at alkaline (pH10) autotrophic medium with sodium carbonate/bicarbonate as the sole source of carbon and amended with sodium thiosulfate as the electron and energy source. The effect of various parameters including temperature (25-40 °C), pH (8-11), NaCl concentration (0.5-5 % w/v) and sodium thiosulfate concentrations (100-750 mM) was evaluated on bacterial growth and thiosulfate removal. This strain could eliminate sodium thiosulfate at very high concentrations up to 750 mM. The results showed that the highest specific growth rate was pH 9.5 and thiosulfate removal of Thioalkalivibrio versutus occurred at pH 10.5. The optimum salt concentration for thiosulfate removal was 2.5 % w/v and 5 % NaCl and specific growth rate elevated 2.5% w/v. It was also specified that this strain thrives occurred in 37 ºC and at 35 and 37 ºC higher removal of thiosulfate. Following chemical oxidation of sulfide to thiosulfate, application of Thioalkalivibrio versutus could be promising for spent caustic treatment. Since thiosulfate is utilized as an energy source, highest removal efficiency occurred at marginally different conditions compared to optimal growth.

Isolation and Characterisation of Sulphur Oxidizing Bacteria Isolated from Hot Spring in Malaysia for Biological Deodorisation of Hydrogen Sulphide in Chicken Manure

“…Various thiosulphate concentrations were tested. 5 mM and 10 mM was set as minimum concentration (Olguin-Lora et al, 2011), 40 mM as initial concentration and 100 mM as a maximum concentration (Makzum et al, 2016). The cultures media were set at pH 8.0 (optimum pH) and incubated at a temperature of 30 °C (optimum temperature) with 160 rpm agitation speed for 7 d. For bacterial growth, 1 mL samples were withdrawn every 24 h and optical density was measured by spectrophotometer at 660 nm.…”