• Mycobiology
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• 제48권1호
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• pp.37-43
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• 2020

A serious leaf disease caused by Colletotrichum dematium was found during the cultivation of Sarcandra glabra in Jingxi, Rong'an, and Donglan Counties in Guangxi Province, which inflicted huge losses to plant productivity. Biological control gradually became an effective control method for plant pathogens. Many studies showed that the application of actinomycetes in biological control has been effective. Therefore, it may be of great significance to study the application of actinomycetes on controlling the diseases caused by S. glabra. Strains of antifungal actinomycetes capable of inhibiting C. dematium were identified, isolated and screened from healthy plants tissues and the rhizospheres in soils containing S. glabra. In this study, 15 actinomycetes strains were isolated and among these, strains JT-2F, DT-3F, and JJ-3F, appeared to show antagonistic effects against anthracnose of S. glabra. The strains JT-2F and DT-3F were isolated from soil, while JJ-3F was isolated from plant stems. The antagonism rate of strain JT-2F was 86.75%, which was the highest value among the three strains. Additionally, the JT-2F strain also had the strongest antagonistic activity when the antagonistic activities were tested against seven plant pathogens. Strain JT-2F is able to produce proteases and cellulase to degrade the protein and cellulose components of cell walls of C. dematium, respectively. This results in mycelia damage which leads to inhibition of the growth of C. dematium. Strain JT-2F was identified as Streptomyces tsukiyonensis based on morphological traits and 16S rDNA sequence analysis.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1868-1873
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• 2006

A novel microorganism that could degrade high molecular weight gellan was screened and isolated from soil. On gellan plate, the microorganism grew well and completely liquefied the plate. The gellan-degrading microorganism was isolated by pure culture on glucose and nutrient agar medium afterwards. The 16S rDNA sequence analysis and biochemical tests using an API 50CHB/20E kit revealed that the strain belonged to Bacillus sp. The isolate, named as Bacillus sp. YJ-1, showed optimum gellan-degrading activity in 0.5% gellan medium at pH 7.5 and 37$^{\circ}C$. The activity was measured and evaluated by the thiobarbituric acid and thin-layer chromatography method. Mass spectrometry revealed that the major gellan.. depolymerized product was an unsaturated tetrasaccharide consisting of $\Delta$4,5-glucuronic acid-(1$\rightarrow$4 )-$\beta$-D-glucose-(1$\rightarrow$4)- $\alpha$-L-rhamnose-(1$\rightarrow$3)-$\beta$-D-glucose, which is a dehydrated repeating unit of gellan, thus the enzyme was identified as gellan lyase. When the gellan was present in the medium, the gellan-degrading activity was much higher than that in glucose-grown cells. These results indicate that in the presence of gellan, Bacillus sp. YJ-1 is able to metabolize the gellan by inducing gellan-degrading enzymes that can degrade gellan into small molecular weight oligosaccharides, and then the gellan. depolymerized products are taken up by the cells and utilized by intracellular enzymes.

• 한국농림기상학회지
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• 제4권4호
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• pp.213-218
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• 2002

국제 기구뿐만 아니라 우리나라에서도 생물 지표를 이용한 환경 모니터링에 관한 관심이 증대하고 있다. 생물 지표는 자국의 국지환경 변화에 잘 반응해야 하므로, 토착 생물지표의 개발은 생태계 복원 및 평가에서 매우 중요한 시발점이다. 환경 스트레스를 달리 받고 있는 남산과 광릉 활엽수림 지역에서 조사된 날개응애 중에서 토양 및 부엽 산도(pH)와 밀접한 관계를 보이는 종을 회귀분석을 통하여 잠재적 생물 지표종으로 선발하였다. 선발된 종은 다음과 같다; Lasiobelba remota, Ceratozetes sp. Tectocepheus velatus, Neogymnobates sp. and Oppia sp.3. 또한 군집구성 및 기능에 매우 중요한 역할을 하는 핵심종(keystone species)으로는, 남산 활엽수림지역에서는 Lohmannia coreana, Ceratozetes sp., Rostrozetes pulcherrimus, Lasiobelba remota 그리고 광릉지역에서는 Neugymnobates sp., Neogymnobates donghaksaensis, Cultroribula tridentata로 나타났다. 생물지표를 이용한 환경 모니터링의 장단점에 대해 고찰하였다.

• 유기물자원화
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• 제14권3호
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• pp.148-156
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• 2006

20,000ppm의 디젤로 오염시킨 토양으로부터 디젤 분해 활성이 있는 균주를 순수분리 하여 이를 동정하고 디젤유 분해능과 특성을 조사하였다. 분리된 균주는 각각 SJD2 및 SJD4로 명명하였으며, 최소배지에 디젤을 유일 탄소원으로 첨가하여 잔류 디젤 농도를 분석한 결과, SJD2 균주는 29.3%의 분해 효율을 가진 것으로 확인되었다. 각 균주의 16s-rDNA 염기서열 분석을 통해 SJD2 균주는 Bacillus fusiformis, SJD4 균주는 Bacillus cereus로 동정되었다. 실제 토양에서의 적용을 위해 microcosm을 제작하여 14일간 토양에서의 디젤 분해능을 측정한 결과, SJD2 균주가 24.9%의 분해 효율을 보였다. 두 균주 모두 $25^{\circ}C-37^{\circ}C$에서 생장이 활발히 일어나 실제 토양에서도 이용이 가능할 것으로 예상되며 pH 7-8, 디젤 농도는 2%일 때 디젤 분해 효율이 가장 높은 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.437-443
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• 2002

A number of soil and wastewater samples were collected from the vicinity of an effluent treatment plant for the chemical industry. Several microorganisms were screened fur their ability to decolorize the triphenylmethane group of dyes. As a result, a novel crystal violet dye-degrading strain LK-24 was isolated. Taxonomic identification including 16S rDNA sequencing and phylogenetic analysis indicated that the isolate had a $99.5\%$ homology in its 16S rDNA base sequence with Stenotrophomonas maltophilia. The triphenylmethane dye, crystal violet, was degraded extensively by growing cells of Stenotrophomonas maltophilia LK-24 in agitated liquid cultures, although their growth was strongly inhibited in the initial stage of incubation. This group of dyes is toxic, depending on the concentration used. The dye was significantly degraded at a relatively lower concentration, below $100{\mu}g\;ml^-1$, yet the growth of the cells was totally suppressed at a dye concentration of $250{\mu}g\;ml^-1$. The degradation products of crystal violet were identified as 4,4'-bis(dimethylamino)-benzophenone and ${\rho}$-dimethylaminophenol by Gas chromatography-Mass spectrometry. The 4,4'-bis(dimethylamino)-benzophenone was easily obtained in a reasonable yield, as it was not metabolized further by S. maltophilia LK-24; however, the ${\rho}$-dimethylaminophenol was not easily identifiable, as it was further metabolized.

• Applied Biological Chemistry
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• 제41권3호
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• pp.208-212
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• 1998

항진균제를 개발하기 위하여 토양으로부터 700주의 세균, 방선균, 곰팡이를 분리하였으며, 이들 배양액을 조사한 결과 Candida albicans의 성장을 억제시킬 수 있는 LAM 97-44 균주를 항진균성 항생물질 생산균으로 선발하였다. 분리균주를 동정하기 위해 생산균 LAM 97-44 균주의 형태학적 특성, 배양학적 특성, 생리학적 특성, 균체성분 등을 조사하였다. LAM 97-44 균주는 $2{\sim}3{\times}1{\sim}1.5\;{\mu}m$ 크기의 포자를 형성하는 간균이며, 포자의 형태는 ellipsoid 형 이었다. LAM 97-44 균주는 arabinose, cellulose, xylose를 이용하지 못하였으나 fructose, glucose, glycerol, maltose, raffinose 등은 이용하는 것으로 나타났다. 지방산 분석결과는 iso-와 anteiso-인 성분으로 구성되어 있었으며, menaquinone은 Bacillus속 세균의 전형적인 isoprenoid 사슬이 7개인 menaquinone(MK-7)이었다. 이러한 결과를 종합하면 LAM 97-44 균주는 Bacillus subtilis와 유사한 균으로 동정되었다.

• 생물환경조절학회지
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• 제16권3호
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• pp.252-257
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• 2007

전남 서남부지역의 참다래 과수원에서 발생하는 과숙썩음병원균(fruit rot, Botryosphaeria dothidea)에 대한 항균작용이 우수한 세균성 균주를 선발하기 위하여 참다래 과수원 토양으로부터 단일균주를 분리하였으며, 과숙썩음병원균(Botryosphaeria dothidea)에 대한 생물적 제어 능력을 검정하고 균주 동정을 실시하였다. 참다래 과수원에서 분리한 총 250여종의 단일균주 중에서 참다래에서 발생하는 과숙척음병원균에 대하여 길항작용이 우수한 균주를 1차적으로 6종 선발하였고, 이 중에서 참다래 과숙썩음병원균에 대하여 길항 작용이 96.0% 정도로 우수한 Strain #120을 최종적으로 선발하였다. 길항균 #120의 포자배열은 rectiflexibles 하였고, 포자표면은 smooth형이었으며, 분리균 세포벽내 LL-type이 DAP를 갖는 wall chemotype I 이었다. 길항균 #120의 균주 형태학적 특성, 생리 생화학적 그리고 화학 분류학적 특성 등을 종합하여 볼 때 길항균 #120은 Streptomyces sp. #120으로 동정되었다.

• Journal of Microbiology and Biotechnology
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• 제25권6호
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• pp.893-902
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• 2015

Various Lactobacillus reuteri strains were screened for the ability to convert glycerol to 1,3-propanediol (1,3-PDO) in a glycerol-glucose co-fermentation. Only L. reuteri DSM 20016, a well-known probiotic, was able to efficiently carry out this bioconversion. Several process strategies were employed to improve this process. Co²⁺ addition to the fermentation medium, led to a high product titer (46 g/l) of 1,3-PDO and to improved biomass synthesis. L. reuteri DSM 20016 produced also ca. 3 µg/g of cell dry weight of vitamin B₁₂, conferring an economic value to the biomass produced in the process. Incidentally, we found that L. reuteri displays the highest resistance to Co²⁺ ions ever reported for a microorganism. Two waste materials (crude glycerol from biodiesel industry and spruce hydrolysate from paper industry) alone or in combination were used as feedstocks for the production of 1,3-PDO by L. reuteri DSM 20016. Crude glycerol was efficiently converted into 1,3-PDO although with a lower titer than pure glycerol (33.3 vs. 40.7 g/l). Compared with the fermentation carried out with pure substrates, the 1,3-PDO produced was significantly lower (40.7 vs. 24.2 g/l) using cellulosic hydrolysate and crude glycerol, but strong increases of the maximal biomass produced (2.9 vs 4.3 g/l CDW) and of the glucose consumption rate were found. The results of this study lay the foundation for further investigations to exploit the biotechnological potential of L. reuteri DSM 20016 to produce 1,3-PDO and vitamin B₁₂ using industry byproducts.

• 한국미생물·생명공학회지
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• 제40권4호
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• pp.303-309
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• 2012

Keratinases are of particular interest because of their action on insoluble keratins and generally on a broad range of protein substrates. Alkalophilic and neutrophilic actinomycete strains isolated from different soil samples, rich in keratinaceous substances were screened for keratinolytic activity. An alkalophilic isolate, TBG-S13A5, was found to possess good keratinolytic activity and was able to utilize feather as the sole carbon and nitrogen source. TBG-S13A5 exhibited an off-white aerial mass color with a rectus-flexibilis type of spore chain. The morphological, microscopical and biochemical characters were comparable with that of Streptomyces albidoflavus. Fatty acid methyl ester profiling (FAME) and 16S rDNA sequence analysis confirmed its identity as a strain of S. albidoflavus. Under submerged fermentation conditions, maximum protease production was recorded on the $5^{th}$ day of incubation at $30^{\circ}C$, using basal broth of pH 9.0 with 0.25% (w/v) white chicken feather. This strain could affect feather degradation when the initial pH was 8 and above and maximum protease production was recorded when the initial pH was around 10.5. The effectiveness of the crude enzyme in destaining and leather dehairing were also demonstrated.

• Journal of Microbiology and Biotechnology
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• 제12권1호
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• pp.71-76
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• 2002

Soil samples were screened for actinomycete strains capable of producing phospholipase D, and a strain, Streptomyces sp. YU100, showing a high transphosphatidylation activity was isolated. This strain secreted phospholipase D in a culture broth after 12 h of cultivation, and its productivity continued to increase for 36 h of fermentation. In addition, its transphosphatidylation rate of phosphatidylcholine to phosphatidylserine was almost $68\%$ within 1 h. The morphological and chemotaxonomical characteristics showed that this strain could be classified as a number of the Streptomycetaceae family, particularly due to the spiral form of its spore chain consisting of 60-70 smooth spores $(0.75{\times}1.0{\mu}m$) on an aerial mycelium, FA-2c type of fatty acid profile in the cell wall, and LL-DAP component in the cell wall peptidoglycan. A phylogenetic analysis of the 16S rDNA provided a clue that the strain YU100 was actually a member of the genus Streptomyces, because the determined sequence exhibited a higher homology with Streptomyes sp. ASB27, S. peucetius JCM9920, and S. griseus ATCC10137. A dendrogram based on the 16S rDNA sequences also showed a phylogenetic relationship between the strain YU100 and these strains. However, the strain YU100 has not yet been assigned to a particular species, because of absence of any other classified species with a high matching score.