Biotechnology Section, Department of Biology, Abiko Research Laboratory, Central Research Institute of Electric Power Industry, Abiko-shi, Japan.
Biotechnol Bioeng. 1993 Mar 15;41(6):671-6. doi: 10.1002/bit.260410611.
Microbial desulfurization might be developed as a new process for the removal of pyrite sulfur from coal sluries such as coal-water mixture (CWM). An application of iron-oxidizing bacterium Thiobacillus ferrooxidans to flotation would shorten the periods of the microbial removal of pyrite from some weeks by leaching methods to a few minutes. The floatability of pyrite in flotation was mainly reduced by T. ferrooxidans itself rather than by other microbial substances in bacterial culture as additive of flotation liquor. Floatability was suppressed within a few seconds by bacterial contact. The suppression was proportional to increasing the number of cells observed between bacterial adhesion and the suppression of floatability. If 25% of the total pyrite surface area covered with the bacteria, pyrite floatability would be completely depressed. Bacteria that lost their iron-oxidizing activities by sodium cyanide treatment were also able to adhere to pyrite and reduced pyrite floatability as much as normal bacteria did. Thiobacillus ferrooxidans ATCC 23270, T-1, 9, and 11, which had different iron-oxidizing abilities, suppressed floatability to similar-levels. The oxidizing ability of bacteria did not influence the suppressing effect. These results showed the mechanism of the suppression of pyrite floatability by bacteria. Quick bacterial adhesion to pyrite induced floatability suppression by changing the surface property from hydrophobic. The quick adhesion of the bacterium was the novel function which worked to change the surface property of pyrite to remove it from coal.
微生物脱硫可能会发展成为一种从煤浆（如煤水混合物）中去除黄铁矿硫的新工艺。将铁氧化细菌氧化亚铁硫杆菌应用于浮选，可以将微生物从某些周的黄铁矿浸出法缩短到几分钟。在浮选过程中，黄铁矿的可浮性主要是由 T. ferrooxidans 本身而不是由细菌培养物中的其他微生物物质作为浮选液的添加剂来降低的。细菌接触几秒钟内就会抑制浮选。抑制作用与细菌粘附和浮选性抑制之间观察到的细胞数量的增加成正比。如果总黄铁矿表面积的 25%被细菌覆盖，黄铁矿的浮选性将完全受到抑制。经氰化钠处理失去铁氧化活性的细菌也能够附着在黄铁矿上，并降低黄铁矿的浮选性，与正常细菌一样。具有不同铁氧化能力的氧化亚铁硫杆菌 ATCC 23270、T-1、9 和 11 将浮选性抑制到相似的水平。细菌的氧化能力不影响抑制效果。这些结果表明了细菌抑制黄铁矿浮选性的机制。细菌对黄铁矿的快速附着通过改变疏水性表面性质诱导浮选性抑制。细菌的快速附着是改变黄铁矿表面性质以将其从煤中去除的新功能。
