• 한국식품과학회지
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• 제16권1호
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• pp.41-46
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• 1984

Aspergillus niger sherumanni IAM 2059가 분비하는 펙틴질분해효소 중에서 endo-polygalacturonase 를 Sephadex G-100, DEAE-Sephadex A-50을 이용하여 분리하고 점도감소와 분해산물분석을 통해 효소의 특성을 조사하였다. Chromatography를 통해 얻은 3 개의 역가 fraction (F-A, F-I 및 F-II) 은 각각 exo형 효소, eodo-polygalacturonase, endo-polymethylgalacturonase 이었다. endo-polygalacturonase의 역가 최적 pH는 환원당 생성으로는 pH4.2 근방이었고 점도감도로는 pH4.7 근방이었다. 이 효소의 Z-value는 $7.5^{\circ}C$이고 $D40^{\circ}C$는 240sec 이며 $40^{\circ}C$에서 활성화엔트로피(Enthalphy of activation) 217.3KJ/mol, 활성화엔트로피(Entropy of activation) 409.2J/mol.K, 활성화자유에너지(Free energy activation) 89.2KJ/mol 이었다.

• 한국축산식품학회지
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• 제43권4호
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• pp.594-611
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• 2023

Whey protein (WP) has nutritional value, but the presence of β-lactoglobulin (β-LG) and α-lactalbumin (α-LA) cause allergic reactions. In this study, hypoallergenic whey protein hydrolyate (HWPH) was prepared by decomposing β-LG and α-LA of WP using exo- and endo-type proteases. The enzyme mixing ratio and reaction conditions were optimized using response surface methodology (RSM). Degradation of α-LA and β-LG was confirmed through gel electrophoresis, and digestion, and absorption rate, and immunostimulatory response were measured using in vitro and in vivo systems. Through RSM analysis, the optimal hydrolysis conditions for degradation of α-LA and β-LG included a 1:1 mixture of Alcalase and Prozyme reacted for 10 h at a 1.0% enzyme concentration relative to substrate. The molecular weight of HWPH was <5 kDa, and leucine was the prominent free amino acid. Both in vitro and in vivo tests showed that digestibility and intestinal permeability were higher in HWPH than in WP. In BALB/c mice, as compared to WP, HWPH reduced allergic reactions by inducing elevated Type 1/Type 2 helper T cell ratio in the blood, splenocytes, and small intestine. Thus, HWPH may be utilized in a variety of low allergenicity products intended for infants, adults, and the elderly.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.481-489
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• 2007

[ $\alpha$ ]-L-Arabinofuranosidases (AFases; EC 3.2.1.55) are exo-type enzymes, which hydrolyze terminal nonreducing arabinose residues from various polysaccharides such as arabinan and arabinoxylan. Genome-wide BLAST search showed that various bacterial strains possess the putative AFase genes with well-conserved motif sequences at the nucleotide and amino acid sequence levels. In this study, two sets of degenerate PCR primers were designed and tested to detect putative AFase genes, based on their three highly conserved amino acid blocks (PGGNFV, GNEMDG; and DEWNVW). Among 20 Bacillus-associated species, 13 species were revealed to have putative AFase genes in their genome and they share over 67% of amino acid identities with each other. Based on the partial sequence obtained from an isolate, an AFase from Geobacillus sp. was cloned and expressed in E. coli. Enzymatic characterization has verified that the resulting enzyme corresponds to a typical AFase. Accordingly, degenerate PCR primers developed in this work can be used for fast, easy, and specific detection and isolation of putative AFase genes from bacterial cells.

• 임산에너지
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• 제20권2호
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• pp.20-27
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• 2001

글루코스 생산을 위한 효과적인 방법을 개발하기 위해서 cellulase에 의한 현사시 나무의 효소가수분해를 실시하였다. 목재의 효소가수분해는 미생물이 생산한 효소를 사용하여 글루코스를 생산하는 반응이다. 이렇게 얻어진 글루코스는 발효에 의해 쉽게 에탄올로 변환시킬 수 있다. 에탄올은 아세톤이나 부탄올, 시트릭산 그리고 락틴산을 제조하는 원료물질이나 석유자원을 대체할 수 있는 대체에너지 자원이다. 셀룰로오스의 효소가수분해 기작은 endo-cellulase, exo-cellulase 그리고 β-D-glucosidase라는 세 개의 서로 다른 형태의 효소가 연속적인 반웅에 의해 일어난다고 설명되어지고 있다. 본 실험의 목적은 다양한 농도의 수산화나트륨으로 현사시나무를 전처리 하여 이러한 전처리가 셀룰로오스의 결정화도와 리그닌함량에 미치는 영향과 가수분해율과의 관계를 조사하였다.

• 한국식품저장유통학회지
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• 제8권2호
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• pp.131-139
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• 2001

Kiyomi tangor(Citus unshiu x sinensis) was stored at 3$\^{C}$ and 85% relative humidity, and the changes in firmness, pectin degrading enzymes activity and other physicochemical properties of citrus fruits during storage were investigated. Decay ratio and weight loss during 180 days’ storage were increased gradually to 13.0% and 12.9%, respectively. Firmness of fruits with 2 mm probe was decreased gradually from 808.7 g-force to 406.4 g-force, and moisture of peel and flesh were decreased from 76.5% to from 89.6% to 87.6% during storage, respectively. Exo-polygalacturonase activity of peel after 150 days’ storage were increased gradually to 558.09 units/100g. Pectin methylesterase activity of peel and flesh were increased from 14.7 units/g to 2.3 units/g, and from 9.4 units/ml to 2.7 units/ml at 150days’ storage, respectively. Endo-polygalacturonase activities were not changed notably during storage. Alcohol-insoluble solid(AIS) of peel was not changed notably. During storage of the fruits water soluble pectin(WSP) of peel and flesh were increased from 474.49 mg/100g to 614.29mg/100g, and from 66.91mg/100g to 92.74mg/100g as wet basis, respectively. Hexameta-phosphate soluble pectin(HMP) of peel were decreased from 405.5mg/100g to 270.43mg/100g, hydochloric acid soluble pectin(HSP) of peel was also decreased from 544.02mg/100g to 412.64mg/100g during storage. Total pectin substance(TPS) of peel and flesh were decreased from 1,424.01mg/100g to 1,297.36mg/100g, and from 165.51mg/100g to 171.54mg/100g, respectively. Composition ratio of pectin was in order of WSP > HSP > HMP.

• 한국미생물·생명공학회지
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• 제26권2호
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• pp.117-121
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• 1998

김치로부터 분리한 Lactobacillus plantarum bacteriophage SC 921은 M.O.I가 0.2일 경우 용균효과가 빠르게 진행됨을 알 수 있었고, SDS-PAGE를 실시하여 phage particle protein을 조사해 본 결과 4개의 major protein으로 구성되어 있는데 이들은 각각 48, 34, 32, 29 kDa으로 구성되어 있다. Exo III로 30분간 반응시킨 후 S1 nuclease를 처리하여 DNA의 형태를 조사해 본 결과 intact DNA는 linear form의 double strand를 유전전달 물질로 가지고 있었다. 제한효소에 대한 절단 효과를 조사한 결과, Sma I에 대해서 1개, Xba I, Cla I, Kpn I, EcoRI에 대해서 각각 2, 4, 5, 6개의 절단부위를 가지고 있으며, Hind III에 대해서는 절단부위가 매우 많은 것을 알 수 있었다. Hind III를 이용하여 intact DNA의 genome size를 측정해본 결과 약 66.5 kbp정도였다. 위의 실험결과와 restriction enzyme mapping을 통해 기존에 알려진 bacteriophage B2와 비교해본 결과 숙주 균주는 같으나 단백질적인 구조나 유전전달물질로 본 구조는 서로 다름을 알 수 있었다.

• 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 Microbiology
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• 제45권5호
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• pp.394-401
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• 2007

In this study, bacterial communities within the guts of several longicorn beetles were investigated by a culture-dependent method. A total of 142 bacterial strains were isolated from nine species of longicorn beetle, including adults and larvae. A comparison of their partial 16S rRNA gene sequences showed that most of the bacteria constituting the gut communities can typically be found in soil, plants and the intestines of animals, and approximately 10% were proposed as unreported. Phylogenetic analysis demonstrated that the bacterial species comprised 7 phyla, and approximately half were Gammaproteobacteria. Actinobacteria were the second most populous group (19%), followed by Firmicutes (13%) and Alphaproteobacteria (11%). Betaproteobacteria, Flavobacteria, and Acidobacteria were minor constituents. The taxonomic compositions of the isolates were variable according to the species of longicorn beetle. Particularly, an abundance of Actinobacteria existed in Moechotypa diphysis and Mesosa hirsute, which eat broadleaf trees; however, no Actinobacteria were isolated from Corymbia rubra and Monochamus alternatus, which are needle-leaf eaters. Considerable proportions of xylanase and pectinase producing bacteria in the guts of the longicorn beetles implied that the bacteria may play an important role in the digestion of woody diets. Actinobacteria and Gammaproteobacteria were the dominant xylanase producers in the guts of the beetles.

• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.397-404
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• 2013

Paenibacillus xylanilyticus KJ-03 was isolated from soil samples obtained from a field with Amorphophallus konjac plants. A gene encoding xylanase was isolated from KJ-03 and cloned using a fosmid library. The xynA gene encodes xylanase; it consists of 1,035 bp and encodes 345 amino acids. The amino acid sequence deduced from the P. xylanilyticus KJ-03 xylanase showed 81% and 69% identities with those deduced from the P. polymyxa E681 and Paenibacillus sp. HPL-001 xylanases, respectively. The xynA gene comprises a single domain, consisting of a catalytic domain of the glycosyl hydrolase (GH) 10 family. The xynA gene was expressed in Escherichia coli BL21 (trxB), and the recombinant xylanase was purified by Niaffinity chromatography. The purified xylanase showed optimum activity with birchwood xylan as a substrate at $40^{\circ}C$ and pH 7.4. Treatment with $Mg^{2+}$ and $Li^+$ showed a slight decrease in XynA activity; however, treatment with 5 mM $Cu^{2+}$ completely inhibited its activity. The results of the thin layer chromatography analysis indicated that the major hydrolysis product was xylobiose and small amounts of xylose and xylotriose. XynA showed increased activity with oat spelt xylan and birchwood xylan, but showed only slight activity with locust bean gum.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1724-1730
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• 2012

An ${\alpha}$-L-arabinofuranosidase (TmAFase) from Thermotoga maritima MSB8 is a highly thermostable exo-acting hemicellulase that exhibits a relatively higher activity towards arabinan and arabinoxylan, compared with other glycoside hydrolase 51 family enzymes. In the present study, we carried out the enzymatic characterization and structural analysis of TmAFase. Tight domain associations found in TmAFase, such as an inter-domain disulfide bond (Cys306 and Cys476) in each monomer, a novel extended arm (amino acids 374-385) at the dimer interface, and total 12 salt bridges in the hexamer, may account for the thermostability of the enzyme. One of the xylan binding determinants (Trp96) was identified in the active site, and a region of amino acids (374-385) protrudes out forming an obvious wall at the substrate-binding groove to generate a cavity. The altered cavity shape with a strong negative electrostatic distribution is likely related to the unique substrate preference of TmAFase towards branched polymeric substrates.