• Journal of Forest and Environmental Science
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• 제24권1호
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• pp.53-59
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• 2008

목질 바이오매스(wood biomass)를 효율적으로 분해하는 최적 배양조건을 확립하기 위하여 국내 침엽수 4수종(소나무, 낙엽송, 잣나무, 리기다소나무)의 목질바이오매스를 혼합하여 목분의 적정입도, 배양기간, 기질첨가농도별 균주의 균체외효소 활성을 측정하였다. 연구 결과, 혼합목분을 기질로 했을때 Fomitopsis palustris가 분비하는 균체외효소 활성은 효소 종류에 따라 기질농도, 목분입도, 및 배양기간등의 배양조건에 따라 다른 효소활성 값을 나타냈다. 침엽수 혼합목분을 기질로 했을 때 대부분의 cellulase 분비를 유도하는 최적 조건은 목분 입도, 80~100 mesh, 기질 농도는 7.5%가 적정한 것으로 밝혀졌다. 또한 최적의 목분입도 및 투입농도 조건에서 배양기간은 4~8주로 적절한 것으로 구명되었다.

• 한국미생물·생명공학회지
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• 제23권3호
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• pp.304-310
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• 1995

A thermophilic bacterium producing the extracellular cellulase-free xylanase was isolated from soil and has been identified as Bacillus sp. The optimal growth temperature was 50$\circ$C and the optimal pH, 7.0. Under the optimal growth condition, maximal xylanase production was 2.2 units/ml in the flask culture. The enzyme production was induced by xylan and xylose, but was repressed by sucrose or trehalose. The partially purified xylanase was most active at 70$\circ$C. It was found that the enzyme was stable at 65$\circ$C for 10 hours with over 75% of the activity. The enzyme was most active at pH 7.0 and retained 90% of its maximum activity between pH 5.0 and pH 9.0 though Bacillus sp. was not grown on alkaline conditions (>pH 8.0). In addition, the activity of xylanase was over 60% at pH 10.0. At the ambient temperature, the enzyme was stable over a pH range of 5.0 to 9.0 for 10 h, indicating that the enzyme is thermostable and alkalotolerant. The activity of xylanase was completely inhibited by metal ions including Hg$^{2+}$ and Fe$^{2+}$, while EDTA, phenylmethylsulfonyl fluoride (PMSF), $\beta$-mercaptoethanol and SDS didn't affect its activity. The enzyme was also identified to exert no activity on carboxymethylcellulose, laminarin, galactomannan, and soluble starch.

• 한국미생물·생명공학회지
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• 제47권4호
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• pp.546-554
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• 2019

This study, for the first time, reports the functional expression of lipase B derived from the yeast Candida antarctica (CALB) in Corynebacterium strain using the Escherichia coli plasmid PK18. The CALB gene fragment encoding a 317-amino-acid protein was successfully obtained from the total RNA of C. antarctica. CALB was readily produced in the Corynebacterium strain without the use of induction methods described in previous studies. This demonstrated the extracellular production of CALB in the Corynebacterium strain. CALB produced in the Corynebacterium MB001 strain transformed with pEC-CALB recombinant plasmid exhibited maximum extracellular enzymatic activity and high substrate affinity. The optimal pH and temperature for the hydrolysis of 4-nitrophenyl laurate by CALB were 9.0 and 40℃, respectively. The enzyme was stable at pH 10.7 in the glycine-KOH buffer and functioned as an alkaline lipase. The CALB activity was inhibited in the presence of high concentration of Mg²⁺, which indicated that CALB is not a metalloenzyme. These properties are key for the industrial application of the enzyme.

• Journal of Microbiology
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• 제41권1호
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• pp.58-62
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• 2003

An extracellular pretense of Bacillus amyloliquefaciens S94 was purified to apparent homogeneity. The enzyme activity was strongly inhibited by general inhibitor for serine protease, PMSF, suggesting that the enzyme is a serine pretense. The purified enzyme activity was inhibited by leucine peptidase inhibitor, bestatin, suggesting that the enzyme is a leucine endopeptidase. The maximum proteolytic activity against different protein substrates occurred at pH 10, 45$^{\circ}C$ (protein substrate) and pH 8, 45$^{\circ}C$ (synthetic substrate). The purified enzyme was specific in that it readily hydrolyBed substrates with Leu or Lys residues at P$_1$ site. The pretense had characteristics of a cold-adapted protein, which was more active for the hydrolysis of synthetic substrate in the range of 15$^{\circ}C$ to 45$^{\circ}C$, specially at low temperature.

• The Korean Journal of Ecology
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• 제18권3호
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• pp.409-418
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• 1995

As a part of studying the function and structure of the mudflat environment of the Yellow Sea, seawater samples in the overlying waters of sediment near Daesan were collected every hour on March 29 (spring tides) and on April 5 (neap tides), 1995 to study the diurnal distribution of aerobic saprophytic bacteria and their extracellular enzyme activities. The diurnal distribution of aerobic saprophytic bacteria ranged from 1.0 X $10^{2}$ to 7.07 X $10^{3}$ cfu /ml at spring tides and from 1.0 X $10^{2}$ to 8.3 X $10^{3}$ cfu /ml at neap tides. The diurnal variations of aerobic saprophytes at the suface waters were greater than those of middle and bottom waters. However, th diurnal fluctuation of saprophyte numbers at spring tides showed no significant difference compared with that at neap tides. The numbers of three physiological groups of aerobic hacteria (proteolytic, lipolytic and amylolytic bacteria) at the surface waters during spring and neap tides were lower than those at the middles and bottom waters. The diurnal variations of five extracellular enzyme activities at the surface waters during the survey period showed lower values than those at the middle and botton waters. Among the measured extracellular enzyme activities, phosphatase showed the highest. However, the activities of amylase, chitinase and cellulase showed a similar tendency.

• Mycobiology
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• 제35권3호
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• pp.162-165
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• 2007

Thirty seven species of Fusarium were evaluated for their ability of producing extracellular enzymes using chromogenic medium containing substrates such as starch, cellobiose, CM-cellulose, xylan, and pectin. Among the tested species Fusarium mesoamericanum, F. graminearum, F. asiaticum, and F. acuminatum showed high ${\beta}$-glucosidase acitivity. Xylanase activity was strongly detected in F. proliferatum and F. oxysporum. Strong pectinase activity was also found in F. oxysporum and F. proliferatum. Amylase activity was apparent in F. oxysporum. No clear activity in cellulase was found from all the Fusarium species tested.

• 미생물학회지
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• 제51권2호
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• pp.108-114
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• 2015

본 연구에서는 Streptomyces subrutilus P5의 생장과 세포내 외 철 함유 superoxide dismutase 활성을 비교 분석하여 철함유 superoxide dismutase의 분비 시점을 확인하고 분자 수준에서 이 효소의 분비에 관여하는 유전정보를 확인하고자 하였다. Streptomyces subrutilus P5의 균체 생장은 건체 중량을 측정하여 결정하였다. Glucose는 log phase에서 급격히 소모되어 24시간 후에 이르러 완전히 고갈되었다. 세포내의 철 함유 superoxide dismutase는 배양 후 3시간에 나타나며 세포외 철 함유 superoxide dismutase는 배양 후 7.5시간부터 나타난다. 따라서 superoxide dismutase는 용균에 의해서가 아니라 능동적인 분비기작에 의해서 세포 외로 분비된 것으로 추측할 수 있다. Streptomyces subrutilus P5의 sodF에는 signal peptide 유전정보가 존재하지 않았다. 그러나 sodF의 상류지역에서 다른 세균의 type III 분비단백질 유전자와 유사한 type III 분비상자가 발견되었다. Streptomyces 균주에서 type III 분비단백질이 존재할 가능성이 있음을 처음으로 제시하였다.

• 미생물학회지
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• 제39권4호
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• pp.230-234
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• 2003

Bacillus amyloliquefaciens psychrotrophic strain이 분비하는 세포 외 단백질 가수분해효소를 정제하여, endopeptidase 활성에 관한 특성을 분석하였다. Protease SE910로 명명된 효소는 단백질 내부의 leucine에 연결된 peptide 결합만을 가수분해하는 endopeptidase로 작용한다. 효소를 특이한 아미노산 잔기에 작용하는 화학수식제와 반응하였을 때 효소의 활성부위에 관여하는 아미노산 잔기가 수식되었을 때는 효소활성이 저해를 받는다. 본 효소는 serine을 수식하는 PMSF에의해 endopeptidase 활성이 완전히 저해되었으며, 카르복실 기능기를 수식하는 화학수식제에 의해 저해되었고, lysine을 화학수식하는 PLP에 의해서는 큰 영향을 받지 않았다. 이것은 본 효소의 endopeptidase 활성에 serine과 aspartic acid 잔기가 관여하는 것을 의미한다. 구조적으로 leucine을 포함하는 유도체인 bestatin은 효소의 endopeptidase 활성을 경쟁적으로 저해하였다.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.861-869
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• 1999

An extracellular protease was purified to homogeneity from the culture supernatant of psychrotrophic bacteria Bacillus sp. JH 108 using procedures including ammonium sulfate fractionation, anion exchange chromatography, gel filtration chromatography, and cation exchange chromatography. The enzyme exhibited a molecular weight of 36 kDa, an optimum pH of 8 to 9, and optimum temperature of $60^{\circ}C$. The enzyme preferentially hydrolyzed leucine at the N-terminus of peptides and thus can be classified as an aminopeptidase. It was strongly inhibited by metal chelating agents such as EDTA and l, l0-phenanthroline. The activity lost by EDTA was restored with $Zn^{2+}{\;}or{\;}Co^{2+}$. These divalent cations also stimulated the native enzyme. This suggests that the enzyme is a metalloprotease acting as a leucine aminopeptidase.

• Journal of Microbiology and Biotechnology
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• 제19권10호
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• pp.1184-1190
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• 2009

A thermostable extracellular $\beta$-mannanase from the culture supernatant of a fungus Aspergillus niger gr was purified to homogeneity. SDS-PAGE of the purified enzyme showed a single protein band of molecular mass 66 kDa. The $\beta$-mannanase exhibited optimum catalytic activity at pH 5.5 and $55^{\circ}C$. It was thermostable at $55^{\circ}C$, and retained 50% activity after 6 h at $55^{\circ}C$. The enzyme was stable at a pH range of 3.0 to 7.0. The metal ions $Hg^{2+}$, $Cu^{2+}$, and $Ag^{2+}$ inhibited complete enzyme activity. The inhibitors tested, EDTA, PMSF, and 1,10-phenanthroline, did not inhibit the enzyme activity. N-Bromosuccinimide completely inhibited enzyme activity. The relative substrate specificity of enzyme towards the various mannans is in the order of locust bean gum>guar gum>copra mannan, with $K_m$ of 0.11, 0.28, and 0.33 mg/ml, respectively. Since the enzyme is active over a wide range of pH and temperature, it could find potential use in the food-processing industry.