• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.364-370
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• 1996

Sediments collected from the Jungnang-cheon and its tributaries were used to enumerate anaerobic bacteria by most probable number (MPN) methods. A simple method was developed to detect ferrous ion in the culture fluid in order to count the number of iron ion reducers, and sulfate-reducing bacteria (SRB) and methanogens were detected by the presence of FeS precipitate in the culture or methane in the head space, respectively. The numbers of iron reducer was in the range of 10$^{7}$ - 10$^{8}$ /g in the sediment of the stream containing higher organic content than the tributaries. The sediments of tributaries were analyzed to contain iron reducers less than 10$^{7}$ cells/g. With one exception the numbers of SRB and methanogens were less than 10$^{3}$ cells/g in the sediment. From these results it is concluded that organics in the sediment support the growth of iron reducers, which out-compete SRB and methanogens.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.65-74
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• 2000

The sensitivity of a mehtanogen and sulfate-reducing bacterium isolated from a sea-based landfill site Cd$^{2+}$ and CU$^{2+}$ was studied. Methanogens and sulfate-reducing bacteria in leachates of the waste disposal site were enumerated using the MPN method. Methanobacterium thermoautotrophicum KHT, isolated from the leachate, could not grow at 0.5 mM Cd$^{2+}$ or 1.0 mM CU$^{2+}$. Desulfotomaculum sp. RHT, isolated from the same leachate, was able to insolubilization 3.0 mM Cd$^{2+}$ or 2.0 mM CU$^{2+}$ by production of hydrogen sulfide. When strains KHT and RHT were cultured together in the presence of the heavy metals, strain KHT could grow at high heavy metal concentrations after insolubilization of the metals by strain RHT. strain RHT.

• Environmental Engineering Research
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• v.19 no.1
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• pp.115-115
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• 2014

• Korean Journal of Microbiology
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• v.10 no.4
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• pp.175-190
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• 1972

This work was designed to illustrate physiological effects on the elimination of sulfur and its compounds in petroleum using sulfur-reducing bacteria. Deulfurizing bacteria were collected from sewage and soil at several areas in Soul and Ulsan, Korea. Seven supecies of sulfur-reducing microbes isolated were identified as : Pseudomonas marginata, Ps.effusa, Ps. putrefaciens, Ps.pseudcmcnelli, Ps. xanthochlora, Ps.bowlesiae, and Ps.aeruginosa. And some experiments were performed to define the growing characteristics of the Pseudomonads and the results obtained are as follows : 1) Shaking culture method was more effective for the growth of the cells than stagnant culture. 2) Beef peptone medium was better for the growth than other media. 3) Cuprous chloride of 50 ppm and cupper sulfate of 300 ppm treated, respectively, in the medium were effective for the growth. 4) Benzene of toluene of 5,000 ppm and petroleum ether of 50,000 ppm did not show remarkable inhibitory effects on the growth.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.191-200
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• 2014

Gas hydrates play a significant role in the global carbon cycle and climate change because methane, a greenhouse gas, can be released from the dissociation of gas hydrate. Anaerobic oxidation of methane (AOM) is an important process that consumes more than 90% of the methane released into the hydrosphere and atmosphere. In this study, the microbial community associated with the methane gas hydrate sediment in the Ulleung basin, East Sea of Korea (UBGH) was analyzed by phylogenetic analysis of the mcrA and 16S rRNA gene libraries. A vertical stratification of the dominating anaerobic methane oxidizer (ANME)-1 group was observed at the surface and the sulfate methane transition zone (SMTZ). The ANME-2c group was found to be dominant in the high methane layer. The archaea of marine benthic group B, which is commonly observed in the AOM region, accounted for more than 50% of the identifications in all sediments. Nitrate reducing bacteria were predominant at SMTZ (Halomonas: 56.5%) and high methane layer (Achromobacter: 52.6%), while sulfate reducing bacteria were not found in UBGH sediments. These results suggest that the AOM process may be carried out by a syntrophic consortium of ANME and nitrate reducing bacteria in the gas hydrates of the Ulleung Basin of the East Sea.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.445-455
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• 2009

Microbiological sulfate reduction is the transformation of sulfate to sulfide catalyzed by the activity of sulfate-reducing bacteria using sulfate as an electron acceptor. Low solubility of metal sulfides leads to precipitation of the sulfides in solution. The effects of microbiological sulfate reduction on in-situ precipitation of arsenic and copper were investigated for the heavy metal-contaminated soil around the Songcheon Au-Ag mine site. Total concentrations of As, Cu, and Pb were 1,311 mg/kg, 146 mg/kg, and 294 mg/kg, respectively, after aqua regia digestion. In batch-type experiments, indigenous sulfate-reducing bacteria rapidly decreased sulfate concentration and redox potential and led to substantial removal of dissolved As and Cu from solution. Optimal concentrations of carbon source and sulfate for effective microbial sulfate reduction were 0.2~0.5% (w/v) and 100~200 mg/L, respectively. More than 98% of injected As and Cu were removed in the effluents from both microbial and chemical columns designed for metal sulfides to be precipitated. However, after the injection of oxygen-rich solution, the microbial column showed the enhanced long-term stability of in-situ precipitated metals when compared with the chemical column which showed immediate increase in dissolved As and Cu due to oxidative dissolution of the sulfides. Black precipitates formed in the microbial column during the experiments and were identified as iron sulfide and copper sulfide. Arsenic was observed to be adsorbed on surface of iron sulfide precipitate.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.843-853
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• 2009

The sediment samples were collected from Seonakdong River and were analyzed for sulfide species such Acid Volatile Sulfide(AVS) and Elemental Sulfur(ES) and Chromium Reducible Sulfide(CRS). Then characteristics of the formation of sulfide species were investigated for six selected samples. Finally the relationship between environmental factors and sulfate reducing rate(SRR) was investigated using two selected samples. Concentrations of AVS and CRS were relatively high, which suggests that organics input to the sediments has been continued until recently and that potential of heavy metals leaching from the sediments is low. SRR in the sediments was closely related to fraction of fine particles(silt+clay) and also to dissolved organic carbon content of the sediment(DOCsed). The dependences of environmental factors such as organic content, temperature, sulfate concentration on the SRR was relatively strong in the selected experiments conducted with the samples from Noksan gate and Daejeo gate samples. The environmental factor dependencies were stronger in the Noksan gate samples than in the Daejeo gate samples, which is probably due to higher surface area of the Noksan gate sediments.

• 한국가스학회:학술대회논문집
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• 2001.10a
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• pp.58-68
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• 2001

Microbiologically influenced corrosion (MIC) of carbon steel gas pipeline in soil environments was investigated at field and laboratory MIC is very severe corrosion and it is not easy to distinguish this corrosion from Inorganic corrosion because of its localized, pitting-type character Therefore, it is important to provide proper assessment techniques for the prediction, detection, monitoring and mitigation of MIC. It is possible to predict the MIC risk, i.e., the activity of sulfate-reducing bacteria (SRB) through the analysis of soil environments. Chemical, microbiological and surface analysis of corrosion products and metal attacked could reveal the possibility of the occurrence of MIC. Various electrochemical and surface analysis techniques could be used for the study of MIC. Among these techniques, thin-film electrical resistance (ER) type sensors are promising to obtain localized corrosion rate of MIC induced by SRB. It is also important to study the effect of cathodic protection (CP) on the MIC In case of coated pipeline, the relationship between coating disbondment and the activity of SRB beneath the disbanded coating is also important.

• Corrosion Science and Technology
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• v.17 no.4
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• pp.147-153
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• 2018

Copper is used in various applications in environments favoring and enabling formation of biofilms by naturally occurring microbes. Copper is also the chosen corrosion barrier for nuclear waste in Finland. The copper canisters should have lifetimes of 100,000 years. Copper is commonly considered to be resistant to corrosion in oxygen-free water. This is an important argument for using copper as a corrosion protection in the planned canisters for spent nuclear-fuel encapsulation. However, microbial biofilm formation on metal surfaces can increase corrosion in various conditions and provide conditions where corrosion would not otherwise occur. Microbes can alter pH and redox potential, excrete corrosion-inducing metabolites, directly or indirectly reduce or oxidize the corrosion products, and form biofilms that create corrosive microenvironments. Microbial metabolites are known to initiate, facilitate, or accelerate general or localized corrosion, galvanic corrosion, and intergranular corrosion, as well as enable stress-corrosion cracking. Sulfate-reducing bacteria (SRB) are present in the repository environment. Sulfide is known to be a corrosive agent for copper. Here we show results from corrosion of copper in anoxic simulated ground water in the presence of SRB enriched from the planned disposal site.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.147-155
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• 2008

The diversity of sulfate reducing bacteria was investigated in different depths of sediments in Lake Sihwa, Korea and Lake Aha, China by PCR amplification, denaturing gradient gel electrophoresis (DGGE) and clone libraries targeting dissimilatory sulfite redectase (dsr) gene. In the analysis of DGGE band patterns, the community compositions of dsr gene in the sediments of both lakes were significantly different whereas bands in all depths of each environment revealed similar patterns. Bands from Lake Sihwa were produced much more than those from Lake Aha, demonstrating a higher diversity of dsr gene in Lake Sihwa. Total 68 clones containing dsr gene were obtained to analyze their sequences. Sequences from the sediment of Lake Sihwa were affiliated to Deltaproteobacteria, the Gram-positive thermophilic sulfate reducers belonging to the genus Desulforomaculum and archaeal thermophilic SRB belonging to the genus Archaeoglobus, whereas sequences from the sediments of Lake Aha were related to genus Desulfotomaculum. Clones retrieved from sediment of Lake Sihwa revealed a higher numbers than those of Lake Aha, demonstrating a higher diversity of dsr gene in Lake Sihwa. Most of clones (59%) were distantly related to the known cultivated SRB with $60\sim65%$ of similarity, which were clustered only the sequences from the environments showed less than 90% similarity. These habitat specific sequences suggested that the clustered dsr sequences represent species or groups of species that were indigenous to these environments. This study showed that these lakes have a specific bacterial communities having dsr gene distinct from those in other environments such as soil and marine ecosystems around the world.