• Environmental Engineering Research
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• 제23권1호
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• pp.62-69
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• 2018

In the present study, long-term heavy metals (HMs) contaminated soil samples from a well-known Pb/Zn smelting area in the southwest of China were collected, and physicochemical and biological characteristics of these samples were evaluated. Soil samples contained different concentrations of HMs, namely Pb, Zn, Cu, and Cd. Enzyme activity analyses combined with microcalorimetric analysis were used for soil microbial activity evaluation. Results showed that two soil samples, containing almost the highest concentrations of HMs, also shared the greatest microbial activities. Based on correlation coefficient analysis, high microbial activity in heavily HMs contaminated soil might be due to the high contents of soil organic matter and available phosphorus in these samples. High-throughput sequencing technique was used for microbial community structure analysis. High abundance of genera Sphingomonas and Thiobacillus were also observed in these two heavily contaminated soils, suggesting that bacteria belonging to these two genera might be further isolated from these contaminated soils and applied for future studies of HMs remediation. Results of present study would contribute to the evaluation of microbial communities and isolation of microbial resources to remediate HMs pollution.

• Journal of Ecology and Environment
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• 제34권4호
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• pp.401-410
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• 2011

We assayed the effects of simulated acid rain on the mass loss, $CO_2$ evolution, dehydrogenase activity, and microbial biomass-C of decomposing Sorbus alnifolia leaf litter at the microcosm. The dilute sulfuric acid solution composed the simulated acid rain, and the microcosm decomposition experiment was performed at 23$^{\circ}C$ and 40% humidity. During the early decomposition stage, decomposition rate of S. alnifolia leaf litter, and microbial biomass, $CO_2$ evolution and dehydrogenase activity were inhibited at a lower pH; however, during the late decomposition stage, these characteristics were not affected by pH level. The fungal component of the microbial community was conspicuous at lower pH levels and at the late decomposition stage. Conversely, the bacterial community was most evident during the initial decomposition phase and was especially dominant at higher pH levels. These changes in microbial community structure resulting from changes in microcosm acidity suggest that pH is an important aspect in the maintenance of the decomposition process. Litter decomposition exhibited a positive, linear relationship with both microbial respiration and microbial biomass. Fungal biomass exhibited a significant, positive relationship with $CO_2$ evolution from the decaying litter. Acid rain had a significant effect on microbial biomass and microbial community structure according to acid tolerance of each microbial species. Fungal biomass and decomposition activities were not only more important at a low pH than at a high pH but also fungal activity, such as $CO_2$ evolution, was closely related with litter decomposition rate.

• 한국지하수토양환경학회지:지하수토양환경
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• 제28권5호
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• pp.68-77
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• 2023

The effect of soil damage on the physicochemical characteristics and activity of the soil microbial community is not well known. This study investigates this relationship by analyzing 11 soil samples collected from various points of soil damage across Gyeonggi-do. Soil damage resulted from forest fires, landslides, and development areas, with their impacts most severe on the topsoil layer (0-30 cm). Dehydrogenase and β-glucosidase activities were notably higher at locations damaged by forest fires compared to other sites. While enzyme activities in soils influenced by landslides and development areas were relatively low, sites with a pollution history exhibited elevated dehydrogenase activity, likely due to past microbial response to the pollution. Additionally, an assessment of carbon substrate usability by soil microorganisms indicated higher substrate availability in areas impacted by forest fires, contrasting with lower availability in landslide and development sites. Statistical analysis revealed a positive correlation between organic content of sand and clay and microbial activity. These findings provide valuable insights into soil damage and associated restoration research, as well as management strategies.

• Journal of Microbiology and Biotechnology
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• 제31권7호
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• pp.978-989
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• 2021

Allyl isothiocyanate (AITC), as a fumigant, plays an important role in soil control of nematodes, soil-borne pathogens, and weeds, but its effects on soil microorganisms are unclear. In this study, the effects of AITC on microbial diversity and community composition of Capsicum annuum L. soil were investigated through Illumina high-throughput sequencing. The results showed that microbial diversity and community structure were significantly influenced by AITC. AITC reduced the diversity of soil bacteria, stimulated the diversity of the soil fungal community, and significantly changed the structure of fungal community. AITC decreased the relative abundance of dominant bacteria Planctomycetes, Acinetobacter, Pseudodeganella, and RB41, but increased that of Lysobacter, Sphingomonas, Pseudomonas, Luteimonas, Pseudoxanthomonas, and Bacillus at the genera level, while for fungi, Trichoderma, Neurospora, and Lasiodiplodia decreased significantly and Aspergillus, Cladosporium, Fusarium, Penicillium, and Saccharomyces were higher than the control. The correlation analysis suggested cellulase had a significant correlation with fungal operational taxonomic units and there was a significant correlation between cellulase and fungal diversity, while catalase, cellulose, sucrase, and urease were the major contributors in the shift of the community structure. Our results will provide useful information for the use of AITC in the assessment of environmental and ecological security.

• 한국지역사회생활과학회지
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• 제21권1호
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• pp.139-148
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• 2010

This study was conducted to restore our traditional Cheongtaejeon tea and to develop the special products. We inoculated Cheongtaejeon tea with lactobacilli (Lactobacillus plantarum CHO 25) and the mixed microbial strains (L. plantarum CHO 25 + Saccharomyces cerevisiae + Bacillus amyloliquefaciens CHO 104). We also examined the sensuous characteristics and physiological activity of Cheongtaejeon tea which was produced by the inoculation of microbial strains. The external appearance of Cheongtaejeon teas were not significant among the teas which were produced with or without the inoculation of L. plantarum CHO 25 and the mixed microbial strains. The taste of the tea increased most in Cheongtaejeon tea which was produced without the inoculation of microbial strains. The taste and liking of Cheongtaejeon tea which was inoculated with Aspergillus oryzae and Aspergillus niger decreased significantly, and it was not suitable to drink. Total phenolics compound contents, total flavonoid contents and DPPH ($\alpha,\alpha$-diphenyl-$\beta$-picryl-hydrazyl) radical scavenging activity of Cheongtaejeon tea extracts increased much more in the order of that produced with the inoculation of L. plantarum CHO 25, control and that with the mixed microbial strains. However, nitrite radical scavenging activity in 1,000 mg/L Cheongtaejeon tea hot water extracts were in the order of the control (94.4%), the inoculation of L. plantarum CHO 25 (93.6%) and the mixed microbial strains (91.1%). Overall results indicated that the sensuous characteristics increased most in Cheongtaejeon tea which was produced without the inoculation of microbial strains, and those physiological activities in tea with the inoculation of L. plantarum CHO 25.

• 미생물학회지
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• 제32권2호
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• pp.163-171
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• 1994

경유를 sandy loam 토양에서 농도별로 투여하여 토양미생물군집에 미치는 영향을 조사하였으며 또한 경우가 첨가된 토양에서 경유의 신속한 제거를 위해 실시한 bioremediation에 의한 영향을 측정하였다. 경유는 토양에서 16주 후 약 50% 내외의 잔류량을 나타내며 bioremediation 처리시 제거율은 60~95% 정도가 증가하여 16주 후 약 8~20 범위의 잔류량을 나타내었다. 토양에 경유가 첨가되었을 때에는 세균직접계수, 진균류의 균사 길이, 호기성 종속영양세균과 탄화수소 분해세균의 수가 최고 10 내지 100배 정도 증가하였다. Bioremediation 처리시에는 그 증가가 더욱 두드러져 각종 미생물 개체수 측정치가 최고 100배 내지 1000배까지 증가하였다. 경유가 fluorescein diacetate 가수분해 활성에 미치는 영향은 bioremediation 처리를 하지 않은 토양에서는 뚜렷한 증감의 경향이 없었으나 bioremediation 처리를 한 토양에서는 10배 내외의 활성의 증가를 보였으며 이러한 양상은 soil dehydrogenase 활성에서도 유사하게 나타났다.

• 한국환경보건학회지
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• 제34권6호
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• pp.403-413
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• 2008

Toxic effect of methyl tert-butyl ether (MTBE), tert-butyl alcohol (TBA) and formaldehyde (FA) on microbial activity and diversity was compared in rice field, leek patch, and tidal mud flat soil samples. MTBE, TBA and FA with different concentrations were added into microcosms containing these soil samples, and placed at room temperature for 30 days. Then the microbial activities such as dehydrogenase and viable cell numbers and microbial community using a DGGE (Denaturing gradient gel electrophoresis) fingerprinting method were measured. Among the samples, dehydrogenase activity in rice field was inhibited the most by MTBE, TBA and FA. The toxic effect was higher according to the following orders: FA > MTBE > TBA. Dominant species in the microcosms contaminated with MTBE, TBA and FA were Chloroflex, Bacilli, gamma-proteobacteria in the rice field sample, Sphingobacteria, Flavobacteria, Actinobacteria, Bacilli, gamma-proteobacteria in the leek patch sample, and Sphingobacteria, Flavobacteria, delta-proteobacteria, gamma-proteobacteria in the tidal mud flat sample.

• 한국기후변화학회지
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• 제5권3호
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• pp.249-256
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• 2014

Permafrost is frozen soil below $0^{\circ}C$ for two or more years. Surface of permafrost is called as active layer that seasonally thaws during the summer. Although the thawing of permafrost may deepen the active layer and consequently increase the microbial activity, the microbial community structure in this habitat has not yet been well described. In this study, we presented bacterial and archaeal diversity in the active layer soil from Resolute, Canada using pyrosequencing analysis. The soil sample was collected from the surface of the marsh covered with moss and Carex. A total of 7,796 bacterial reads for 40 phyla and 245 archaeal reads for 4 phyla were collected, reflecting the high diversity of bacteria. Predominant bacterial groups were Proteobacteria (37.7%) and Bacteroidetes (30.0%) in this study. Major groups in Archaea were Euryarchaeota (51.4%) and Thaumarchaeota (46.1%). Both methane producing archaea and consuming bacteria were detected in this study. Although it might be difficult to characterize microbial community with only one sample, it could be used for the basis of assessing the relative importance of the specific groups with a high resolution on the bacterial and archaeal community in this habitat.

• 한국토양비료학회지
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• 제48권4호
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• pp.262-270
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• 2015

The scientific information between microbial community and chemical properties of reclaimed tidal soil is not enough to understand the land reclamation process. This study was conducted to investigate the relation between chemical properties and microbial activities of soils from reclaimed tidal lands located at south-western coastal area (42 samples from Goheuong, Samsan, Bojun, Kunnae, Hwaong and Yeongsangang sites). Most of the reclaimed soils showed chemical characteristics as salinity soil based on EC. Only $Na^+$ in exchangeable cation was dependent on EC of reclaimed soil, whereas other cations such as $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were independent on EC. The mesophilic bacteria decreased with an increase in EC of soil. Microbial population increased with soil organic content in the range of $0{\sim}10g\;kg^{-1}$ and dehydrogenase activity less than $100{\mu}g-TPF\;g^{-1}h^{-1}$. Microbial population of soils from reclaimed tidal lands was closely related to the microbial community containing hydrolytic enzyme activities of cellulase, amylase, protease, and lipase.

• Journal of Microbiology and Biotechnology
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• 제33권6호
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• pp.760-770
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• 2023

Continuous cropping obstacles have become a serious factor restricting sustainable development in modern agriculture, while companion planting is one of the most common and effective methods for solving this problem. Here, we monitored the effects of companion planting on soil fertility and the microbial community distribution pattern in pepper monoculture and companion plantings. Soil microbial communities were analyzed using high-throughput sequencing technology. Companion plants included garlic (T1), oat (T2), cabbage (T3), celery (T4), and white clover (T5). The results showed that compared with the monoculture system, companion planting significantly increased the activities of soil urease (except for T5) and sucrase, but decreased catalase activity. In addition, T2 significantly improved microbial diversity (Shannon index) while T1 resulted in a decrease of bacterial OTUs and an increase of fungal OTUs. Companion planting also significantly changed soil microbial community structures and compositions. Correlation analysis showed that soil enzyme activities were closely correlated with bacterial and fungal community structures. Moreover, the companion system weakened the complexity of microbial networks. These findings indicated that companion plants can provide nutrition to microbes and weaken the competition among them, which offers a theoretical basis and data for further research into methods for reducing continuous cropping obstacles in agriculture.