Microbial Reduction of Vitamin B12 by Shewanella alga Strain BrY with Subsequent Transformation of Carbon Tetrachloride

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• 作者：Darla J. Workman ; Sandra L. Woods ; Yuri A. Gorby ; Jim K. Fredrickson ; and Michael J. Truex
• 刊名：Environmental Science & Technology
• 出版年：1997
• 出版时间：August 1997
• 年：1997
• 卷：31
• 期：8
• 页码：2292 - 2297
• 全文大小：146K
• 年卷期：v.31,no.8(August 1997)
• ISSN：1520-5851

文摘

The ability of a metal-reducing bacterium to microbiallyreduce vitamin B₁₂ was determined to expand ourunderstanding of the role vitamin B₁₂ plays in thetransformationof halogenated compounds in microbial systems. Thesubsequent transformation of chlorinated methanescatalyzed by this microbially-reduced vitamin B₁₂ wasthenevaluated. When incubated in the presence ofShewanellaalga strain BrY and an electron donor, the microbialreductionof vitamin B_12a to B_12r was observed as a shiftin the vitaminB₁₂ spectrum. In treatments containing vitaminB₁₂ and anelectron donor but without BrY, the predominant specieswas vitamin B_12a. The introduction of BrY into thesystemresulted in the production of vitamin B_12r. Thetransformationof carbon tetrachloride (CT), chloroform (CF), anddichloromethane (DCM) was examined in batch systemscontaining vitamin B₁₂, Shewanella alga strainBrY, and anelectron donor. Transformation of both CT and CF wasobserved, while no significant change in the DCMconcentration was detected. Carbon monoxide was the majorproductof CT transformation. No significant transformation ofCTor CF was detected when vitamin B₁₂ was omittedfromthe system. This work demonstrates that ametal-reducingbacterium, with no apparent ability to transform CT or CFdirectly, mediates the reduction of vitamin B₁₂, whichinturn catalyzes the transformation of CT.