Relationship between copper biosorption and microbial inhibition of hydroxyl radical formation in a copper(II)–hydrogen peroxide system
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The original publication is available at www.springerlink.comThe microbial retardation of the spin adduct, DMPO-OH, formed in a copper(II)-###hydrogen peroxide-DMPO (5,5-dimethyl-1-pyrroline N-oxide) solution was examined in###relation to copper biosorption. A hydroxyl radical is formed in the solution through two steps, the reduction of Cu(II) to Cu(I) by H2O2 and the Fenton-type reaction of Cu(I) with H2O2. The resultant radical is trapped by DMPO to form DMPO-OH. Microbial cells retarded the DMPO-OH in the Cu(II)-H2O2-DMPO far more significantly than in the UV-irradiated H2O2- DMPO solution. Egg albumin showed a higher DMPO-OH retardation than microbial cells both in the Cu(II)-H2O2-DMPO and the UV-irradiated H2O2-DMPO solutions. These results indicated that the retardation effect is related to organic matter and not to microbial activity.###Microorganisms having higher affinities for copper ion retarded DMPO-OH more###significantly. The linear relationship between the amounts of copper biosorption and the inverse of the median inhibitory doses for DMPO-OH indicated that the microbial cells inhibited the reduction of Cu(II) to Cu(I) by H2O2, followed by the decrease of hydroxyl radical formation and the retardation of DMPO-OH. These results also suggest that the coupling between microbial cells and Cu(II) ion can be estimated from their ability to retard###DMPO-OH.
- World journal of microbiology & biotechnology
World journal of microbiology & biotechnology, 2007-11-15