• Journal of Microbiology and Biotechnology
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• 제16권2호
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• pp.200-204
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• 2006

The enzymology of an activated sludge system for a petroleum wastewater purification process was investigated. Leucine-aminopeptidase (L-AMP), ${\beta}$-glucosidase (${\beta}-GLC$), and lipase (LIP) were selected for the study. It was found that more than 81.7% of enzymatic activity was associated with microbial cells in the activated sludge floc. The metabolic response of a mixed microbial population to increased phenol concentration showed that L-AMP activity increased in the activated sludge, whereas activities of ${\beta}-GLC$ and LIP decreased, due to the inhibitory effect of the phenol which varied from 100 mg/l to 500 mg/l.

• Journal of Applied Biological Chemistry
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• 제43권3호
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• pp.165-169
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• 2000

Regarding to maturity evaluation of pig manure compost mixed with saw dust, change of constituents of organic matter influenced by microbial activities were investigated. Throughout the two stages of active composting period, we obtained a lot of data related to compost stabilization. However, we found out that only a couple of parameters could be used for adequate evaluation of compost. We, therefore, decided that total sugar and reducing sugar could be used for the reasonable standard criteria of maturity during composting process, even though some enzyme activities by phosphates and cellulase reactions were obtained and compared. Because the other parameters such as contents of lignin, cellulose, and organic acids were difficult to be used for maturity evaluation of pig manure compost.

• Archives of Pharmacal Research
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• 제11권1호
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• pp.61-64
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• 1988

To investigate the antibiotic constituents of Korean basidiomycetes the carpophores of the wood-rotting basidiomycetes were collected from several locations of Korea, and from them 17 mycelial strains were isolated on potato-dextrose-agar plates supplemented with tetracycline ($20\;{\mu}g/m{\ell}$. The isolated strains were shake-cultured in glucosepeptone-yeast extract medium and then the antibacterial activities of the culture filtrates were assessed by disc-plate method. Among them, 12 strains (70.6%) were active, and basidiomycete strain LMCB-109 (Daedalea quercina) and LMCB-116 showed potent activities against all the six bacterial target organisms including Serratia marcescens.

• 한국환경보건학회지
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• 제34권4호
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• pp.327-332
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• 2008

To determine structure and activities of microbial communities in a food wastewater treatment system, biofilm of RABC (rotating activated Bacillus contactor) and samples of aeration tanks were analyzed. Heterotrophic bacterial concentrations were similar between biofilm and stage 1 aeration tank and decreased 2-log at stage 3 aeration tank as dissolved oxygen decreased, however portions of Bacillus groups were increased at stage 3 aeration tank. It was revealed by quantitative and qualitative analysis of metabolic fingerprinting patterns of Biolog GN2 plate that RABC represented much higher activities and a different microbial community structure compared to aeration tanks. Metabolic fingerprinting showed the carbon sources that isolated Bacillus groups could or could not use, were used similarly meaning that not only Bacillus groups but also other microbial groups would contribute to the treatment of wastewater.

• 한국토양비료학회지
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• 제44권1호
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• pp.146-159
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• 2011

The continuous increase in the production of metals and their subsequent release into the environment has lead to increased concentration of these elements in agricultural soils. Because microbes are involved in almost every chemical transformations taking place in the soil, considerable attention has been given to assessing their responses to metal contaminants. Short-term and long-term exposures to toxic metals have been shown to reduce microbial diversity, biomass and activities in the soil. Several studies show that microbial parameters like basal respiration, metabolic quotient, and enzymatic activities, including those of oxidoreductases and those involved in the cycle of C, N, P and other elements, exhibit sensitivity to soil metal concentrations. These have been therefore, regarded as good indices for assessing the impact of metal contaminants to the soil. Metal contamination has also been extensively shown to decrease species diversity and cause shifts in microbial community structure. Biochemical and molecular techniques that are currently being employed to detect these changes are continuously challenged by several limiting factors, although showing some degree of sensitivity and efficiency. Variations and inconsistencies in the responses of bioindicators to metal stress in the soil can also be explained by differences in bioavailability of the metal to the microorganisms. This, in turn, is influenced by soil characteristics such as CEC, pH, soil particles and other factors. Therefore, aside from selecting the appropriate techniques to better understand microbial responses to metals, it is also important to understand the prevalent environmental conditions that interplay to bring about observed changes in any given soil parameter.

• 한국균학회지
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• 제5권2호
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• pp.25-30
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• 1977

• 한국환경보건학회지
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• 제32권2호
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• pp.192-197
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• 2006

This study was performed to investigate anti-microbial activity of soybean extract against oral microbes, and to determine the minimum inhibition concentration (MIC) for microbes causing oral diseases. The soybean extract was prepared using ethyl acetate and it was treated with 16 types of oral microbes at a concentration of 5.00 mg/ml (0.5%). The MIC of soybean extract for three major microbes causing oral diseases was determined. The anti-microbial activity and MIC were measured using broth dilution method. Significant reduction of microbial activities of 9 types oral microbes when the soybean extract was added to the broth compared to the control (p<0.01). The extract showed higher anti-microbial activity against some anaerobic strains (P. gingivalis and P. intermieia). S. mutans, which causes dental caries, showed MIC at a concentration of 40 mg/ml for the soybean extract. P. gingivalis, which causes adult periodontal disease, showed MIC at a concentration of 20 mg/ml for the extract. C. albicans, which causes denture stomatitis and angular stomatitis, showed MIC at a concentration of 20 mg/ml for the extract. These results indicate that soybean extract showed anti-microbial effort against 9 types of oral microbes, and the anti-microbial effect of the extract against oral microbes was stronger against fungi than against bacteria. The anti-microbial mechanism of soybean extract against oral microbes should be investigated, and more research for clinical application is required at a level of actual intake.

• 한국균학회지
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• 제49권4호
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• pp.441-454
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• 2021

Fungal diseases including anthracnose, stem rot, blight, wilting, and root rot of crops are caused by phytopathogens such as Colletotrichum species, Sclerotinia sclerotiorum, Phytophthora species, and Fusarium oxysporum and F. solani which threaten the production of chili pepper. In this study, to identify biological control agents (BCAs) of phytopathogenic fungi, potentially useful Bacillus species were isolated from the field soils. We screened out five Bacillus strains with antagonistic capacity that are efficiently inhibiting the growth of phytopathogenic fungi. Bacillus species were characterized by the production of extracellular enzymes, siderophores, and indole-3-acetic acid (IAA). Furthermore, the influence of bacterial strains on the plant growth promoting activity and seedling vigor index were assessed using Brassica juncea as a model plant. Inoculation with Bacillus subtilis SRCM 121379 significantly increased the length of B. juncea shoots and roots by 45.6% and 52.0%, respectively. Among the bacterial isolates, Bacillus subtilis SRCM 121379 showed the superior enzyme activities, antagonistic capacity and plant growth promoting effects. Based on the experimental results, Bacillus subtilis SRCM 121379 (GenBank accession no. NR027552) was finally selected as a BCA candidate.

• 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.

• 한국토양비료학회지
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• 제44권1호
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• pp.127-145
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• 2011

Various environmental ecosystems are valuable sources for microbial ecology studies, and their analyses using recently developed molecular ecological approaches have drawn significant attention within the scientific community. Changes in the microbial community structures due to various anthropogenic activities can be evaluated by various culture-independent methods e.g. ARISA, DGGE, SSCP, T-RFLP, clone library, pyrosequencing, etc. Direct amplification of total community DNA and amplification of most conserved region (16S rRNA) are common initial steps, followed by either fingerprinting or sequencing analysis. Fingerprinting methods are relatively quicker than sequencing analysis in evaluating the changes in the microbial community. Being an efficient, sensitive and time- and cost effective method, T-RFLP is regularly used by many researchers to access the microbial diversity. Among various fingerprinting methods T-RFLP became an important tool in studying the microbial community structure because of its sensitivity and reproducibility. In this present review, we will discuss the important developments in T-RFLP methodology to distinguish the total microbial diversity and community composition in the various ecosystems.