• Korean Journal of Microbiology
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• v.24 no.2
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• pp.133-140
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• 1986

Extracts of CO-autotrophically grown cells of Acinetobacter sp. 1 were shown to use thionin, methylene blue, or 2,6-dichlorophenol-indophenol, but not NAD, NADP, FAD, or FMN, as electron acceptors for the oxidation of CO under strictly anaerobic conditions. The CO dehydrogenase (CO-DH) in the thes bacterium was found to be an inducible enzyme. The enzyme activity was determined by an assay based on the CO-dependent reduction of thionin. Maximal reaction rates were found at pH 7.5 and $60^{\circ}C$, and the Arrhenius plot revealed an activation energy of 6.1 kcal/mol(25.5kJ/mol). THe $K_m$ m/ for CO was $154{\mu}M$. Known metalchelating agents tested had no effects on the CO-DH activity. No divalent cations tested affect the enzyme activity significantly escept $Cu^{2+}$ which suppressed the activity completely. The enzyme was inhibited by glucose and succinate. The same extracts catalyzed oxidation of hydrogen gas and formate with thionin as electron acceptor. The CO-DH of Acinetobacter sp. 1 was to have no immunological relationship with that of Pseudomonas carboxydohydrogena.

• Advances in environmental research
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• v.1 no.3
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• pp.201-210
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• 2012

The bioavailability of sorbed organic contaminants is one of the most important factors used to determine their fate in the environment. This study was conducted to evaluate the bioavailability of slow-desorbable naphthalene in soils. An air sparging system was utilized to remove dissolved (or desorbed) naphthalene continuously and to limit the bacterial utilization of dissolved naphthalene. A biological air sparging system (air sparging system with bacteria) was developed to evaluate the bioavailability of the slow-desorption fraction in soils. Three different strains (Pseudomonas putida G7, Pseudomonas sp. CZ6 and Burkholderia sp. KM1) and two soils were used. Slow-desorbable naphthalene continuously decreased under air sparging; however, a greater decrease was observed in response to the biological air sparging system. Enhanced bioavailability was not observed in the Jangseong soil. Overall, the results of this study suggests that the removal rate of slow-desorbable contaminants may be enhanced by inoculation of degrading bacteria into an air sparging system during the remediation of contaminated soils. However, the enhanced bioavailability was found to depend more on the soil properties than the bacterial characteristics.

• Environmental Engineering Research
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• v.15 no.2
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• pp.57-62
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• 2010

The purpose of this study was to investigate the effect of mixing methods on the biodegradation of sorbed naphthalene and phenanthrene in soils. Biodegradation was initiated by inoculating Pseudomonas sp. KM1 into equilibrated soil slurry vials. Four different mixing methods, including no mixing, orbital shaking, rolling and rotating were utilized to enhance the biodegradation of both naphthalene and phenanthrene. The experimental results showed that the sorbed compounds were more effectively biodegraded with rolling and rotating mixing methods. The sorbed naphthalene concentrations were reduced to 0 mg/kg via the rolling and rotating methods. However, with no mixing and the orbital shaking methods, the sorbed naphthalene concentrations were comparatively high, ranging from 2.59 to 20.45 mg/kg. Similar trends were observed for the biodegradation of phenanthrene, but the concentrations remaining were higher than those of naphthalene, due to the limited bioavailability of the sorbed phenanthrene. The rolling and rotating mixing methods are suggested can distribute bacteria uniformly in the slurry system; improve the mass transfer rate and the probability of physical contact between bacteria and the sorbed contaminants, resulting in higher bioavailability of the contaminants.