Sulfate-reducing microorganisms

Arsenic is another element with different bioavailabiUty in its different redox states. Arsenic is not known to be an essential nutrient for eukaryotes, but arsenate (As(V)) and arsenite (As(III)) are toxic, with the latter being rather more so, at least to mammals. Nevertheless, some microorganisms grow at the expense of reducing arsenate to arsenite (81), while others are able to reduce these species to more reduced forms. In this case it is known that the element can be immobilized as an insoluble polymetallic sulfide by sulfate reducing bacteria, presumably adventitiously due to the production of hydrogen sulfide (82). Indeed many contaminant metal and metalloid ions can be immobilized as metal sulfides by sulfate reducing bacteria. 

Heat can be used to break some emulsions Changing the pH of the water can often break an emulsion The presence of acid-forming and sulfate-reducing microorganisms may enhance the formation of emulsions treat the fuel with a microbiocide Formulate fuels with a demulsifier to inhibit emulsion formation Ensure that surfactant compounds and additives... 

Edwards, E. A., Wills,L. E., Reinhard, M. Grbic-Galic, D. (1992). Anaerobic degradation of toluene and xylene by aquifer microorganisms under sulfate-reducing conditions. Applied and Environmental Microbiology, 58(3), 794-800. 

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