• 한국미생물·생명공학회지
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• 제32권4호
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• pp.366-370
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• 2004

Four chitinase producing bacteria, Arthrobacter nicotinae CH4, Arthrobacter nicotinae CHI3, Arthrobacter sp. CH5 and Micrococcus sp. CH3, were isolated from small crabs and shrimps. We investigated the optimum medium condition for the production of enzyme and high cell mass. The preferable medium composition was as follows: colchitin 0.1 %(w/v), glycerol 0.25%(w/v) and yeast extract 0.05%(w/v) in minimal midium ($K_{2}HPO_{4}$ 0.7 g/l, $KH_{2}PO_{4}$ 0.3 g/l, $MgSO_{4}{\cdot}5H_{2}O$ 0.5 g/l, $FeSO_{4}}{\cdot}7H_{2}O$ 0.01 g/l, $ZnSO_{4}$ 0.001 g/l, $MnCI_2$ 0.001 g/l, pH 7.0). This cell culture medium could be used directly as sample for measuring chitinase activity. Because it hardly conreducing sugar such as glucose (blank value=0), the detected reducing sugar can be considered as a chitinase reaction product. The results can be used for easy preparation method for determination of enzyme activity and analysis of enzyme-substrate reaction in step of screening of chitinase producing bacteria.

• 식물병연구
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• 제21권3호
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• pp.222-226
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• 2015

The chitinase-producing bacterial strain C-1 is one of the key chitinase-producing biocontrol agents used for effective bioformulations for biological control. These bioformulations are mixed cultures of various chitinolytic bacteria. However, the precise identification, biocontrol activity, and the underlying mechanisms of the strain C-1 have not been investigated so far. Therefore, we evaluated in planta biocontrol efficacies of C-1 and determined the draft genome sequence of the strain in this study. The bacterial C-1 strain was identified as a novel Serratia sp. by a phylogenic analysis of its 16S rRNA sequence. The Serratia sp. C-1 bacterial cultures showed strong in planta biocontrol efficacies against some major phytopathogenic fungal diseases. The draft genome sequence of Serratia sp. C-1 indicated that the C-1 strain is a novel strain harboring a subset of genes that may be involved in its biocontrol activities.

• KSBB Journal
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• 제29권3호
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• pp.131-138
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• 2014

In this study, we isolated two novel chitinase producing bacterial strains from yellow loess samples collected from Jullanamdo province. The chitinase producing bacteria were isolated based on the zone size of clearance in the chitin agar plates. Both of them were gram positive, rod ($2{\sim}3{\times}0.3{\sim}0.4{\mu}m$), spore-forming, and motility positive. They were facultative anaerobic, catalase positive and hydrolyzed starch, gelatin, and casein. From the 16s rRNA gene sequence analysis, the isolates were labeled as Bacillus licheniformis KYLS-CU01 and B. licheniformis KYLS-CU02. The isolates showed higher extracellular chitinase activities than B. licheniformis ATCC 14580 as a control. The optimum temperature and pH for chitinase production were $40^{\circ}C$ and pH 7.0, respectively. Response Surface Methodology (RSM) was used to optimize the culture medium for efficient production of the chitinase. Under this optimal condition, 1.5 times higher chitinase activity of B. licheniformis KYLS-CU02 was obtained. Extracellular chitinases of the two isolates were purified through ammonium sulfate precipitation and anion-exchange DEAE-cellulose column chromatography. The specific activities of purified chitinase from B. licheniformis KYLS-CU01 and B. licheniformis KYLS-CU02 were 7.65 and 5.21 U/mg protein, respectively. The molecular weights of the two purified chitinases were 59 kDa. Further, the purified chitinase of B. licheniformis KYLS-CU01 showed high antifungal activity against Fusarium sp.. In conclusion, these two bacterial isolates can be used as a biopesticide to control pathogenic fungi.

• 식물병연구
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• 제23권1호
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• pp.19-34
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• 2017

유기농 및 지속 가능한 농산물에 대한 최근의 전 세계적인 수요는 농가 현장에서 사용 가능한 생물 농약의 개발 및 활용에 대한 요구가 증대되고 있다. 그러나 대부분의 생물학적 방제 방법은 실제 현장 조건에서 식물병 방제 스펙트럼이 제한적이고 효능이 높지 않다. 본 연구팀은 키틴분해 미생물과 키틴을 활용하여 적은 비용으로 방제효과가 우수한 키틴 기반 제형을 개발했다. 이 제형은 포장 조건에서 다양한 식물병을 성공적으로 방제하였다. 본 리뷰에서는 성공적인 포장 연구와 관련하여 이 제형에 함유되어 있는 키틴분해미생물들의 생태학적 측면과 생물적 방제 기작에 대해 기술하였다. 또한 현장에서 키틴분해미생물의 현장 대량 배양과 효과적인 생물학적 방제 방법을 사용하여 농민 친화적인 수단으로 확대 할 수 있는 생물적 방제 방법과 전략의 가능성에 대해 논의했다.

• Journal of Applied Biological Chemistry
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• 제61권3호
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• pp.233-238
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• 2018

Chitinases are glycosyl hydrolases which cleave the ${\beta}$-1,4 linkage of chitin into oligo or monomers of N-acetylglucosamine. These bacterial enzymes have been used for a wide range of applications in the food and pharmaceutical industries. In this study, we isolated two potential chitinolytic strains, BAO-01 and BAO-02, from salt-fermented shrimp, which were shown to belong to the genus Salinivibrio through genetic characterization using 16S rRNA. These isolates were gram-positive, rod-shaped, and non-spore forming. BAO-01 showed greater growth and chitinase activity than BAO-02 after the incubation at $37^{\circ}C$ for 4 days. Both strains grew on a wide range of carbon and nitrogen sources, pH values, temperatures, and salt levels. However, they showed minor biochemical differences. In addition, their antimicrobial activities against foodborne pathogens and antibiotic susceptibilities were evaluated. These Salinivibrio spp. did not show bioamine production, hemolytic activity, and mucin degradation. Therefore, the in vitro screening results suggested that these bacteria could be widely used as new candidates for chitin hydrolyzation and seafood fermentation.

• 미생물학회지
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• 제41권4호
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• pp.293-299
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• 2005

인삼근권토양으로부터 분리된 총640 저영양세균 중 유일한 탄소원으로 colloidal chitin을 첨가한 배지에서 투명환을 나타낸 8균주를 선발하였다. 대부분의 균주가 chitin의 형광성 유사체인 4-methylumbelliferyl D-N,N'-diacetylchitobioside (MUF-diNAG)을 분해하였고, CR-42균주의 경우 4-methylumbelliferyl-D-glucosaminide (MUF-NAG)를 분해하였다. 이들 chitinase 생산균주의 16S rDNA 염기서열을 결정하여 계통학적 위치를 확인한 결과 5개의 주요한 계통군: proteobacteria $\gamma-subdivision$ (3균주), proteobacteria $\beta-subdivision$ (1 균주), Actinobacteriaceae (1 균주), Bacillaceae (1 균주) 그리고 Bacteriodetes (2 균주)로 분류되었다. 이들 분리균주 중 WR164와 CR18 균주는 16S rDNA염기서열의 유사도가 미배양 및 미동정 등록균주와 $97\%$ 미만으로 나타나 신규미생물로 제안할 수 있는 균주로 예상되었다. 한편 CR2와 CR75 chitinase 생산균주는 인삼 탄저 병원균인 Colletotrichum gloeosporioides의 생장을 저해하는 것으로 나타났다.

• 한국식품과학회지
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• 제35권6호
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• pp.1188-1192
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• 2003

새우나 게 껍질로부터 chitin을 유일한 탄소원으로 하는 집적배양에 의하여 chitinase 활성이 우수한 균주를 2종 분리하였다. 분리균주는 형태학적, 그람염색, 16s rDNA 서열분석을 통하여 Arthrobacter nicotianae로 동정되어, 각각 Arthrobacter nicotianae CH4와 Arthrobacter nicotianae CH13으로 명명하였다. 두 종의 분리균주로부터의 chitinase는 모두 pH $3.0{\sim}9.0$에서 90% 이상의 효소활성을 유지하여 높은 pH안정성을 나타내었다. 온도의 영향은 $20{\sim}60^{\circ}C$ 구간에서 최적 효소 활성의 $70{\sim}90%$를 유지하여 열안정성도 뛰어났다. A. nicotianae CH4와 A. nicotianae CH13이 분비하는 chitinase 조효소를 0.1% colloidal chitin 기질에 반응시켜서 반응산물로 생산되는 chitin 올리고당을 HPLC를 사용하여 분석하였다. A. nicotianae CH4 조효소에 의한 효소반응산물로는 올리고머인 $(GlcNAc)_4$이, A. nicotianae CH13는 단량체인 $(GlcNAc)_1$이 전체 반응산물의 각각 98% 이상 생성되었다.

• Journal of Applied Biological Chemistry
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• 제49권4호
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• pp.171-175
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• 2006

Chitin compost and broth were used to suppress club root. Individual cabbage seedlings were transplanted into pots(3500 ml) containing a mixture of 3% chitin compost and 50 ml of chitin broth (T1) or the same quantity control compost and control compost broth(T2). The media in each pot was then infected with Plasmodiophora brassicae. Samples were taken at 6, 7 and 8 weeks after transplanting. The population of chitinase producing bacteria in T1 was consistently larger than that observed in T2. Chitinase activity in the T1 rhizosphere was two-fold greater than that of T2 at each time point observed. Shoot dry weight, leaf number and leaf area in T1 were enhanced 20%, 10% and 12% relative to those seen in T2, respectively. The disease index and root mortality at 8 weeks after transplanting were reduced by 50% and 25% in T1 compared to T2, respectively. Results presented in this study are strongly indicative that chitin compost and broth suppress clubroot in Chinese cabbage.

• 한국환경농학회지
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• 제30권3호
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• pp.346-356
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• 2011

BACKGROUND: Chemical fungicides not only may pollute the ecosystem but also can be environmentally hazardous, as the chemicals accumulate in soil. Biological control is a frequently-used environment-friendly alternative to chemical pesticides in phytopathogen management. However, the use of microbial products as fungicides has limitations. This study isolated and characterized a three-antifungal-enzyme (chitinase, cellulase, and ${\beta}$-1,3-glucanase)-producing bacterium, and examined the conditions required to optimize the production of the antifungal enzymes. METHOD AND RESULTS: The antifungal enzymes chitinase, cellulase, and ${\beta}$-1,3-glucanase were produced by bacteria isolated from an sawmill in Korea. Based on the 16S ribosomal DNA sequence analysis, the bacterial strain AM50 was identical to Streptomyces sp. And their antifungal activity was optimized when Streptomyces sp. AM50 was grown aerobically in a medium composed of 0.4% chitin, 0.4% starch, 0.2% ammonium sulfate, 0.11% $Na_2HPO_4$, 0.07% $KH_2PO_4$, 0.0001% $MgSO_4$, and 0.0001% $MnSO_4$ at $30^{\circ}C$. A culture broth of Streptomyces sp. AM50 showed antifungal activity towards the hyphae of plant pathogenic fungi, including hyphae swelling and lysis in P. capsici, factors that may contribute to its suppression of plant pathogenic fungi. CONCLUSION(S): This study demonstrated the multiantifungal enzyme production by Streptomyces sp. AM50 for the biological control of major plant pathogens. Further studies will investigate the synergistic effect, to the growth regulations by biogenic amines and antifungal enzyme gene promoter.

• 한국해양생명과학회지
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• 제7권2호
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• pp.121-128
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• 2022

L-asparaginase (ASNase) is a therapeutic enzyme used to treat acute lymphoblastic leukemia. Currently, the most widely used ASNases are originated from bacteria. However, owing to the adverse effects of bacterial ASNases, new resources for ASNase production should be explored. Fungal enzymes are considered efficient and compatible resources of natural products for diverse applications. In particular, fungal species belonging to the genus Trichoderma are well-known producers of several commercial enzymes including cellulase, chitinase, and xylanase. However, enzyme production by marine-derived Trichoderma spp. remains to be elucidated. While screening for extracellular ASNase-producing fungi from marine environments, we found four strains showing extracellular ASNase activity. Based on the morphological and phylogenetic analyses using sequences of translation elongation factor 1-alpha (tef1α), the Trichoderma isolates were identified as T. afroharzianum, T. asperellem, T. citrinoviride, and Trichoderma sp. 1. All four strains showed different ASNase activities depending on the carbon sources. T. asperellem MABIK FU00000795 showed the highest ASNase value with lactose as a carbon source. Based on our findings, we propose that marine-derived Trichoderma spp. are potential candidates for novel ASNase production.