• 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.

• 한국유기농업학회지
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• 제23권1호
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• pp.77-89
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• 2015

본 연구는 수박 과실썩음병의 원인균인 Acidovorax avenae subsp. citrulli 균에 대해서 항균활성을 갖는 친환경 유기농자재를 개발할 목적으로 약용식물 133종을 대상으로 진행되었다. 이들 133종 약용식물의 MeOH 추출물에 대한 bioassay를 통해 항균 활성을 검정한 결과 청피(Citrus unshiu Markovich) 추출물에서 강한 항균활성을 보였다. 청피(Citrus unshiu Markovich)로부터 항균활성물질을 구명하고자 용매분획을 하였고, 용매분획 중에서 hexane fraction이 가장 강한 활성을 나타내었다. Hexane fraction을 GC-MS로 분석하여 chromatogram상의 각각의 peak에 해당하는 mass spectrum과 Wiley library를 비교하여 profiling 한 결과, essential oil인 d-limonene, ${\gamma}$-terpinene, ${\beta}$-linalool, terpineol과 지방산인 palmitic acid, 9,12-octadecadienoic acid, linolenic acid 그리고 steroid 화합물인 stigmasterol이 검출되었다. 이들 검출화합물 중에서 항균 활성물질로 추정되는 d-limonene, ${\gamma}$-terpinene, ${\beta}$-linalool, terpineol의 항균 활성을 검정하기 위해 표준품을 사용하여 bioassay한 결과 두 화합물 d-limonene, ${\gamma}$-terpinene에서 높은 항균활성을 보였다. 따라서 본 연구를 통해 청피로부터 분리한 d-limonene과 ${\gamma}$-terpinene 화합물이 항균 활성물질인 것을 구명하였다. 항균력이 강한 청피 추출물 또는 d-limonene과 ${\gamma}$-terpinene을 주성분으로 하는 추출물을 수박 과실썩음병에 대한 친환경 방제용 자제로 개발이 가능할 것으로 판단되었다.

• 한국토양비료학회지
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• 제46권2호
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• pp.122-128
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• 2013

본 연구는 제주지역 농경지 이용유형과 토양특성별 미생물체량과 탈수소효소활성을 평가 하고자 수행하였다. 제주지역 밭(50), 과수원(50), 논(30), 시설재배(30) 토양을 3월에 채취 후 토양화학성과 탈수소효소활성, 미생물체량을 분석하였다. 밭 토양의 평균 pH는 6.3이었고 과수원, 시설재배지 토양은 조사지점간에 화학성분 함량의 차이가 크게 나타났다. 돈분퇴비를 시용하는 감귤재배농가의 토양 내 아연과 구리함량은 증가하는 경향을 보였다. 토양 탈수소효소활성과 미생물체량은 농경지 이용유형에 상관없이 비화산회 토양이 화산회토양보다 높았다. 탈수소효소활성은 밭 토양이 과수원, 논, 시설재배지 토양보다 2-4배 이상 높았고 비화산회토의 밭토양은 38.7 ug TPF $24^{h-1}g^{-1}$를 나타냈다. 미생물체량은 시설재배지 토양이 가장 많았으며 시설재배지 비화산회토양은 216.8 $mg\;kg^{-1}$였다. 시설재배지의 비화산회토양은 탈수소효소활성과 토양유기물($R^2$=0.59), 아연($R^2$=0.65), 구리($R^2$=0.66)의 함량간에 높은 정의 상관관계를 보였다. 화산회토의 밭토양은 유기물함량과 탈수소효소 활성간에 높은 부의상관관계($R^2$=0.57)를 나타냈다.

• Journal of Microbiology and Biotechnology
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• 제20권2호
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• pp.254-264
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• 2010

To obtain an efficient natural lignocellulolytic complex enzyme, we screened an efficient lignocellulose-degrading composite microbial system (XDC-2) from composted agricultural and animal wastes amended soil following a long-term directed acclimation. Not only could the XDC-2 degrade natural lignocelluloses, but it could also secrete extracellular xylanase efficiently in liquid culture under static conditions at room temperature. The XDC-2 degraded rice straw by 60.3% after fermentation for 15 days. Hemicelluloses were decomposed effectively, whereas the extracellular xylanase activity was dominant with an activity of 8.357 U/ml on day 6 of the fermentation period. The extracellular crude enzyme noticeably hydrolyzed natural lignocelluloses. The optimum temperature and pH for the xylanase activity were $40^{\circ}C$ and 6.0. However, the xylanase was activated in a wide pH range of 3.0-10.0, and retained more than 80% of its activity at $25-35^{\circ}C$ and pH 5.0-8.0 after three days of incubation in liquid culture under static conditions. PCR-DGGE analysis of successive subcultures indicated that the XDC-2 was structurally stable over long-term restricted and directed cultivation. Analysis of the 168 rRNA gene clone library showed that the XDC-2 was mainly composed of mesophilic bacteria related to the genera Clostridium, Bacteroides, Alcaligenes, Pseudomonas, etc. Our results offer a new approach to exploring efficient lignocellulolytic enzymes by constructing a high-performance composite microbial system with synergistic complex enzymes.

• 한국식생활문화학회지
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• 제18권2호
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• pp.111-122
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• 2003

This studies were performed to develop a Korean traditional folk liquor namely Gangha-ju has been prepared at Bosung district in Korea, and manufacturing conditions and anti-oxidation activity and anti-microbial activity of Gangha-ju were investigated. Ethyl-alcohol 20% and 30% Gangha-ju were brewed with glutinous rice wine, distilled liquor and 6 herbs of ginger, cinnamon, etc. Chemical and physical properties of 30% Gangha-ju were acidity 0.22, pH 4.31, amino acidity 3.26, transmittance 59 and conductivity $911\;{\mu}s/m$, and 20% Gangha-ju were 0.43, 4.20, 6.26, 62 and $924\;{\mu}s/m$. Volatile flavor compounds of ethyl alcohol, acetic acid, butanol, n-amyl alcohol, iso-pentyl alcohol, ethyl acetate, butyl acetate, acetaldehyde and furfural were detected, and main aroma compounds of Gangha-ju were isopentyl alcohol and ethyl acetate. Anti-oxidation activity by DPPH method was evaluated 31.32%, and nitrite scavenging effect was 31.79%. Anti-microbial activity against several microorganisms was pronounced strong activity over a wide range of test organisms, and Leuconostoc mesenteroids and Salmonella Ttyphimurium, Staphylococcus epidermidis were found to be more sensitive to Gangha-ju than Escherichia coli and Aspergillus flavus.

• Mycobiology
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• 제40권2호
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• pp.138-141
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• 2012

We measured physiological functionalities, including antihypertensive angiotensin I-converting enzyme inhibitory activity and immun-stimulating ${\beta}$-glucan content for sixty kinds of Makgeolli that is commercially available from the market. As a result, we selected R-12 commercial raw Makgeolli, with a high content of immuno-stimulating ${\beta}$-glucan, and R-14 commercial raw Makgeolli, exhibiting high antihypertensive activity. Due to the similarities in their overall physicochemical properties and raw materials used for fermentation, we compared the microbial flora in order to investigate the reason for the differences in their functionalities. Nested PCR and denaturing gradient gel electrophoresis for yeasts and bacteria were performed for analysis of microbial diversity of two different kinds of Makgeolli (i.e., R-12, R-14), which showed immuno-stimulating ${\beta}$-glucan content and exhibited a very high level of antihypertensive activity, respectively. Analysis of the 18S rDNA amplicon revealed a major presence of the yeast strain Pichia burtonii in every Makgeolli sample. Analysis of the 16S rDNA amplicon revealed a predominance of lactic acid bacteria, and the most frequent lactic acid bacteria were Lactobacillus ingluviei, L. fermentum, and L. harbinensis, and Lactobacillus sp. Among these, L. harbinensis was detected only in R-12 and L. ingluviei was found only in R-14. Different functionalities from the individual commercially available Makgeolli may be attributed to actions of different microbial flora during fermentation.

• 한방비만학회지
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• 제18권2호
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• pp.64-73
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• 2018

Objectives: This study investigated the effect on microbial ecology, fermentation characteristics and anti-obesity of Platycodon grandiflorum (PG) fermentation with salt. Methods: PG was fermented for four weeks with 2.5% salt and the characteristics of fermented PG were performed by measuring pH, total sugar content, viable bacteria number and microbial profiling. Also, we measured total polyphenol, flavonoid and the percent of inhibition of lipase activity and lipid accumulation. Results: Salt added to PG for fermentation had an effect on pH, total sugar, total and the number of lactic acid bacteria. Total sugar and pH were reduced and number of total and lactic acid bacteria were increased after fermentation. The majority of bacteria for fermentation were Lactobacillus plantarum, Leuconostoc psedomesenteroides and Lactococcus lactis subspecies lactis regardless of salt addition. However, microbial compositions were altered by added salt and additional bacteria including Weissella koreensis, W. viridescens, Lactobacillus sakei and Lactobacillus cuvatus were found in fermented PG with salt. Total flavonoid was increased in fermented PG and lipid accumulation on HepG2 cells treated with fermented PG was reduced regardless of salt addition. Moreover, fermented PG without salt suppressed lipase activity. Conclusions: Addition of salt for PG fermentation had influence on fermentation characteristics including pH and sugar content as well as number of bacteria and microbial composition. In addition, fermented PG showed anti-obesity effect by increasing flavonoid content and inhibition of lipase activity and lipid accumulation.

• 한국환경보건학회지
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• 제34권5호
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• pp.387-394
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• 2008

The toxicity of methyl tert-butyl ether (MTBE), tert-butyl alcohol (TBA) and formaldehyde (FA) on the indigenous microbial community in forest soil was studied. MTBE, TBA and FA with different concentrations were added into microcosms containing forest soil samples. After 10 and 30 days, total viable cell number and dehydrogenase activity in the microcosms were evaluated. Bacterial communities in the microcosms were also analyzed using a denaturing gradient gel electrophoresis (DGGE). Dehydrogenase activity and total viable cell number were decreased according to the increase of MTBE, TBA and FA concentrations (P<0.05). FA toxicity was the highest, but TBA toxicity was the lowest. The results of principal component analysis using DGGE fingerprints showed that the microbial communities contaminated MTBE, TBA and FA were grouped by exposure time not exposure concentration. Dominant species in the microcosms were as follows: Photobacterium damselae sub sp. and Bacillus sp. KAR28 for MTBE; Mycobacterium sp. and Uncultured Clostridium sp. for TBA; and Uncultured Paenibacillaceae bacterium and Anxynobacillus, Flavithermus for FA.

• 한국미생물·생명공학회지
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• 제48권3호
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• pp.358-365
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• 2020

An organic solvent- and bleach-stable protease-producing strain was isolated from a polluted river water sample and identified as Aeromonas veronii OB3 on the basis of biochemical properties (API 20E) and 16S rRNA sequence analysis. The strain was found to hyper-produce alkaline protease when cultivated on fish waste powder-based medium (HVSP, 4080 U/ml). The biochemical properties and compatibility of OB3 with several detergents and additives were studied. Maximum activity was observed at pH 9.0 and 60℃. The crude protease displayed outstanding stability to the investigated surfactants and oxidants, such as Tween 80, Triton X-100, and H₂O₂, and almost 36% residual activity when incubated with 1% SDS. Remarkably, the enzyme demonstrated considerable compatibility with commercial detergents, retaining more than 100% of its activity with Ariel and Tide (1 h, 40℃). Moreover, washing performance of Tide significantly improved by the supplementation of small amounts of OB3 crude protease. These properties suggest the potential use of this alkaline protease as a bio-additive in the detergent industry and other biotechnological processes such as peptide synthesis.

• The Korean Journal of Ecology
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• 제18권4호
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• pp.503-512
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• 1995

The present paper describes partial results of the study on the activities of microbes in the soil of Quercus mongolica forest from July, 1994 to April, 1995. To determine the relationship between structure and function of soil microbial ecosystem, the author investigated the seasonal change of physical environmental factors, microbial population and soil enzyme activities. The changes of pH was not significant and the temperature of surface soil was 2℃ higher than lower soil through out the year. Moisture contents (％) of soil samples ranged from 7.64％ to 42.11％. However, soils of site 3 at Mt. Komdan in which vegetation is successional have higher moisture content than the others. The bacterial population increased in summer, but continuously decreased in autumn and winter, and then reincreased again in spring. Bacterial population of surface soil was higher than those of 30 cm depth all the year round. Dehydrogenase activity (DHA) was about two-fold higher throughout in surface soil compared to those of lower soil. And the correlation coefficient between DHA and bacterial population size was 0,713, It was suggested that DHA could be used as a primary index of soil microbial population and activity in soil ecosystem.