• Journal of Applied Biological Chemistry
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• 제51권4호
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• pp.143-147
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• 2008

Purified atrazine chlorohydrolase (AtzA) was entrapped in the nanoparticles of biomimetically synthesized silica at the ambient condition within 20 min. Entrapped AtzA in biomimetic silica was less affected by pH change and showed higher thermostability than free enzymes. The entrapped AtzA was also more tolerant against proteolysis, with 80% of the initial activity remaining and retained 82% of the initial activity even after four cycles of usage. These results suggest that entrapment of AtzA in biomimetic silica could be utilized under diverse environmental conditions with the active catalytic performance sustained.

• 약학회지
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• 제53권3호
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• pp.114-118
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• 2009

Bioemulsifiers are those chemicals which are produced from microorganisms but which have both hydrophilic and hydrophobic groups. $\alpha$-Glucosidase inhibitor ($\alpha$-GI) produced from Bacillus lentimorbus B-6 (B-6) showed bioemulsifying activity. But $\beta$-glucosidase inhibitor produced from B-6 didn't show emulsifying activity. $\alpha$-GI was purified from supernatant of B-6 grown in minimal culture medium containing glucose and sodium glutamate by Sephadex G-100 column chromatography and isolated from $\beta$-GI by dialysis against water. Toluene was determined as the best substrate for emulsifying activity of $\alpha$-GI. $\alpha$-GI showed thermostability at $100^{\circ}C$ for 15 min, high salt tolerance up to 32% NaCl and wide range of pH-stability at pH $4\sim10$. Emulsifying character of $\alpha$-GI can be useful for the liposome formation for the treatment of diabetes mellitus.

• 산업기술연구
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• 제29권A호
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• pp.169-176
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• 2009

The gene encoding endoxylanase (xylS) was isolated from a genomic library of Bacillus licheniformis NBL420. Two positive clones, which harbor 1.5 kb and 0.8 kb inserts respectively, were screened on RBB dyed-xylan plates and the recombinant plasmids were named as pBX3 and pBX5. The nucleotide sequencings of two inserts revealed the existence of common 639 bp of open reading frame which encode 232 amino acids. The xylS gene was successfully subcloned into pET22b(+) vector and overexpressed. Enzymatic properties including optimum pH, optimum temp, thermostability and pH stability were investigated. Activity staining of XylS was identical with that of original Bacillus licheniformis NBL420.

• 한국환경과학회지
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• 제6권3호
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• pp.225-229
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• 1997

호염기성 V. vulnificus는 연안에 존재하는 미생물로서 치명적인 상처 감염과 생명을 위협하는 패혈증과 관련이 있다. Hemolysin은 V. vulnificus를 포함하는 여러 가지 세균종에 의해 생성되는 독성 물질이다. 본 연구에서는 해양 V. vulnificus에서 hemolysin을 정제한 후 hemolysin의 활성에 미치는 pH, 온도 및 금속 이온의 영향을 조사하였다. Hemolysin은 sheep red blood cell을 용혈시켰으며 hemolysin의 최적 pH는 8.0, 최적 온도는 4$0^{\circ}C$이었으며 $K^+$ 이온은 homolysin의 활성을 증가시켰으나 $Mn^{2+}$는 감소시켰다. 그러나 hemolysin은 열에 불안정하였다.

• Journal of Oral Medicine and Pain
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• 제7권1호
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• pp.77-85
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• 1982

Identification of blood group from dental hard tissue for the purpose of individual identification of a highly burned corpse would play a significant role in a practical legal medicine. The author conducted a study of blood group with teeth left stading at a high temperature by the method of elution test. The following results were obtained. 1. The blood identifcation from heated dental hard tissue proved to be possible. 2. In cases of heat-treated theeth at $100^{\circ}C$ for 120 minutes, at $150^{\circ}C$ for 120 minutes and at $200^{\circ}C$ for 45 minutes for A.B.O(H) blood group, the identification of blood group was possible. 3. In case of heat-treated teeth, thermostability of blood group was found to be $150^{\circ}C$. 4. The adequate surface area for the detection of blood group was 40-80 meshes.

• Food Science and Biotechnology
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• 제18권3호
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• pp.655-660
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• 2009

Biotechnological phytase preparations are commercially available and are currently used in animal feeding. However, thermostability constraints, low yields, and the high cost of the enzyme have limited its use. This study represents a new perspective for the food enzyme market. The research screened thermostable yeast strains for their ability to produce phytase. The screening was carried out with a gradual increase in temperature ($30-48^{\circ}C$). Sixteen strains (1 strain identified as Saccharomyces cerevisiae) maintained the ability to produce phytase at $48^{\circ}C$ and their phytase activity was confirmed using 2 phytase assay methodologies. The yeast strains tested in this study seem to be potential efficient producers of phytase, indicating a possible new source of thermostable phytase of commercial interest, particularly that from S. cerevisiae.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1976년도 제7회 학술발표회
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• pp.184.5-184
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• 1976

In the course of studies on thermostable liquefying amylase from thermostable Bacillus spp., we have isolated a strain which produces amylase activity. This strain was identified to be Bacillus stearothermophlus. The amylase of this strain demonstrated a maximum activity at 65$^{\circ}C$ and Ca$\^$＋＋/ did not improve thermostability of the enzyme although the erzyme was capable of hydrolyzing starch at temperature of 80$^{\circ}C$ and above. The maximum amount of the enzyme was product at pH 7.0, 50$^{\circ}C$.

• 한국미생물·생명공학회지
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• 제22권3호
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• pp.259-265
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• 1994

A bacteriocin-producing lactic acid bacteria was isolated from contaminated milk products, which was identified by using the API50 CH kit as Lactococcus lactis subsp. lactis with reliability of 98%. Fatty and analysia of the cell membrane showed that this strain contained same fatty acids profiles as type strain, Lactococcus lactis subsp. lactis ATCC 19435. The bacteriocin of Lactococcus sp. HY 449 showed relatively wide range of inhibition spectrum against gram positive and some gram negative bacteria such as Escherichia coli and maintained the inhibitory activity between pH2.0 and pH9.0 The thermostability of this bacteriocin was higher in acidic solution than in distilled water and was stable at 60$\circ $C for 1 hour.

• 한국미생물·생명공학회지
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• 제40권3호
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• pp.186-189
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• 2012

A gene coding for mannanase (manA) from Bacillus subtilis was introduced into a shuttle vector pGK12 between Escherichia coli, B. subtilis and Lactobacillus paracasei. As a result of transferring the resultant plasmid, designated pGK12M3, into three different strains, the manA gene was found to be expressed in L. paracasei as well as in B. subtilis and E. coli. In a 4 L fermentor culture, the production of mannanase by recombinant L. paracasei (pGK12M3) reached a maximum level of 5.4 units/ml in an MRS medium with a fixed pH 6.5. Based on the zymogram of mannanase, it is assumed that mannanase produced by recombinant L. paracasei is not maintained stably with proteolytic degradation. The optimal temperature and thermostability of mannanase produced by recombinant L. paracasei were also found to be different from those of enzymes produced by B. subtilis.

• Bulletin of the Korean Chemical Society
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• 제19권3호
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• pp.308-313
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• 1998

A thermally irreversible photochromic system, 2,3-bis(2,4,5-trimethyl-3-thienyl)maleic anhydride (MTMA), has been studied by semi-empirical molecular orbital methods. There are one pair of stable conformations for the closed-ring form and three pairs for the open-ring form, each pair consisting of two mirror-image conformations. Interconversion between the parallel and anti-parallel conformations of the open-ring form is restricted due to high energy barriers. Only the anti-parallel conformation appears to be responsible for photochromic cyclization. Thermostability of the compound is attributed to an avoided crossing at high energy in the ground states of the isomers, whereas the photoreactivity can be explained by the mutually connected excited singlet (S1) states of the isomers, forming a double well potential with a low energy barrier. The large solvent effects can be partly explained with the low dipole moment of the anti-parallel conformation of MTMA in the S1 state. The large variation of quantum efficiency suggests that excess vibronic energy can be utilized to provide the activation energy for the photochromic reaction.