Colorless Sulfur Bacteria Screening And Utilizing For Sulfur Production

The colorless sulfur bacteria have now been shown to be able to obtain energy from the oxidation of reduced sulfur compounds (e.g., sulfide, sulfur and organic sulfides) for growth.Common oxidation products of sulfide will be for elemental sulfur (in vivo either removes) or sulfate according to the condition.The colorless sulfur bacteria play an essential role in biological treatment to reduce sulfur compounds in the waste water and in the waste gas.The screening of new strains with higher desulphurization performance is the foundation.In this study, two colorless sulfur bacteria were isolated from the sulfur sludge of the sewage treatment plant, respectively, named as strain 1 and strain 2.Of these two kinds of bacteria, the morphological, physiological and biochemical characteristics, optimal growth conditions, have been inspected, and the strains have been studied about the metabolic pathways for sulfur compounds oxidation through the wastewater treatment trials, some influencing factors of the metabolic pathways were studied.The study indicated that the cells of strain 1 were rod shape, gram-negative, facultative growth.The optimal grow condition was 30℃,pH 7.0;the rotation speed was 100 r/min.The cells of strain 2 were spherical shaped, gram-negative, facultative growth. The optimal grow condition was 37℃,pH 6.0;the rotation speed was 200 r/min.Laboratory studies have shown that sodium sulfide or the sodium hyposulfite can be oxidized to elemental sulfur by strain 1 or strain 2, they can obtain energy from the oxidation. In the simulation experiment of wastewater containing sodium sulfide treatment by strain 1 and strain 2, under optimum growth conditions, when the sodium sulfide concentration of simulated wastewater was 300 mg/L,wastewater inoculated OD600 value of 0.8,processing time was 12 h, strain 1 had higher sodium sulfide oxidation capacity. The oxidation rate of sodium sulfide into elemental sulfur was 46.32%.Strain 2 was cultivated in the optimum growth conditions, when the sodium sulfide concentration of simulated wastewater was 100 mg/L,wastewater inoculated OD600 value of 0.8, processing time was 12 h, strain 2 have higher sodium sulfide oxidation capacity. The oxidation rate of sodium sulfide into elemental sulfur was 35.29%.This research will have great theoretic significance and practical value in the exploitation of biotechnological sulfide removal.Strain 1 and strain 2 have certain application value to the industry desulphurization, strain 1 and strain 2 was provided as strain resources in the development of desulfurization technology. These provided a theoretical foundation for the control of sulfur producing process during biological treatment for wastewater containing sulfide.