Title: Formation of Sulfide by Some Sulfur Bacteria.
Abstract:Previous studies with the strictly autotrophic sulfur bacterium, Thiobacillus thioöxidans, growing on elemental sulfur have shown that the sulfur is rapidly oxidized to sulfate without the accumulatio...Previous studies with the strictly autotrophic sulfur bacterium, Thiobacillus thioöxidans, growing on elemental sulfur have shown that the sulfur is rapidly oxidized to sulfate without the accumulation of intermediate products. The strictly autotrophic sulfur bacterium Th. thioparus transforms thiosulfate to the 2 products, sulfate and elemental sulfur. No question has arisen concerning the initial stages of transformation of thiosulfate, but, by reason of the relatively large size of the particles of elemental sulfur compared to the tiny bacterial cells (about 0.5 × 0.8μ) it has been suggested that some initial transformation to a reduced or oxidized substance may precede passage of the sulfur material through the cell membrane, after which the reactions leading to the release of energy for growth takes place. However, McCallan and Wilcoxon present evidence which shows that the vapor pressure of elemental sulfur is sufficiently high to permit sulfur vapor to enter cells which are not even in contact with the solid sulfur. Inorganic media containing sulfur or thiosulfate and supporting growth of these 2 bacteria have been examined for the presence of sulfide. No sulfide or other reducing substance was detected in cultures of Th. thioöxidans by titration with 0.01N iodine. No substance formed from thiosulfate by Th. thioparus was found by titration with iodine. Tests for sulfide with nitroprusside were negative in both cases. The results do not support the contention of von Deines that the sulfur material precipitated by Th. thioparus during growth on thiosulfate is a highly sulfured polysulfide. Although sulfide does not appear in detectable amounts in the media, sulfide is produced by both organisms during growth.Read More
Publication Year: 1936
Publication Date: 1936-10-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 7
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