Microbiology

Living Off Anesthetic

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Science  29 Jan 2010:
Vol. 327, Issue 5965, pp. 505
DOI: 10.1126/science.327.5965.505-c
CREDIT: JUPITERIMAGES

Toxicity concerns have largely eliminated chloroform's erstwhile use as an anesthetic, though the compound still plays a role in industrial chemistry. Low levels of chloroform (trichloromethane) inhibit the metabolisms of bacteria responsible for detoxifying many other chlorinated hydrocarbons; therefore, its persistence in the environment not only presents a possible human health risk but also slows down natural remediation processes. Now, however, Grostern et al. have discovered a population of Dehalobacter that can not only tolerate a high level of chloroform but actually grow on it by coupling dechlorination to respiration. Kinetics studies suggest that the bacteria use a reductive dehalogenase enzyme specific to chloroform and the structurally similar trichloroethane. Direct reduction of chloroform coupled to bacterial growth is advantageous for remediation because it is more efficient and does not require the addition of separate growth substrates. Contaminated aquifers—such as the one from which these bacteria were originally isolated—may be fertile grounds for other bacteria with specialized adaptations to tolerate toxins.

Environ. Microbiol. 12, 10.1111/j.1462-2920.2009.02150.x (2010).

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