Cadmium inhibition of the biological removal of mercury from contaminated waste

Conference · Thu Dec 31 23:00:00 EST 1987

OSTI ID:7036498

Choudhury, G S; Hansen, C L ^[1]

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1. Dept. of Nutrition and Food Sciences, Utah State Univ., Logan, UT (US)

Toxic and potentially hazardous heavy metals are found in waste water from many industrial sources. Among these compounds, mercury is one of the most toxic and significant examples of heavy metal pollution. Mercury resistant strains of bacteria have been successfully used for biological detoxification of mercury. A concentration of 70 mg/L of mercury was tolerated and successfully removed by volatilization from the influent sewage. The continuous mercury removal was accomplished by a relatively stable mixed population of mercury resistant bacteria under non- sterile conditions. The detoxification of mercury carried out by mercury resistant bacteria is believed to be a NADPH dependent enzyme catalyzed reduction of mercuric ion to volatile metallic mercury. The enzyme responsible for this transformation is mercuric reductase which is a soluble flavoprotein located in the cytoplasm. Mechanistically, it is similar to enzymes in the class of FAD containing disulfide reductases and requires an excess of exogenous thiols for activity. Biological processes that employ microorganisms to achieve various biochemical transformations are sensitive to the presence of toxic organic and inorganic compounds. Metals, especially the heavier ones, are one of the toxicant groups that Inerfxere with the activities of microorganisms. According to Rinderle et al. and Izaki, cadmium, silver, copper and gold are potent inhibitors of the enzyme mercuric reductase. For the successful design and control of biological reduction of mercuric ion to metallic mercury in complex waste streams, an understanding is needed of the influence of additional components in the waste stream on the rate and efficiency of mercury volatilization. This book describes the study which was undertaken in an attempt to evaluate the effects of cadmium on the biological detoxification of mercury in defined media.

• OSTI ID: 7036498
• Report Number(s): CONF-880679--
• Country of Publication: United States
• Language: English

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HYDROGEN COMPOUNDS
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