• Journal of Forest and Environmental Science
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• v.24 no.1
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• pp.53-59
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• 2008

Extracellular enzyme activities of Fomitopsis palustris were determined by the particle sizes, culture periods and concentrations of wood particle substrate which was mixture of 4 domestic coniferous woods, such as Pinus densiflora, Larix leptolepsis, Pinus koraiensis, and Pinus rigida. The results showed that the culture conditions had an effect on the secretion of most of the extracellular enzymes from Fomitopsis palustris in the mixed wood particle substrate. :The optimal culture conditions for enzyme activities were 80~100 mesh in wood particle size, 7.5% in concentrations of wood substrate, and 4~8 weeks in culture period.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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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.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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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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• v.41 no.1
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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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• v.18 no.3
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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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• v.35 no.3
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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.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.108-114
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• 2015

We tried to analyze the growth time for secretion of the iron containing superoxide dismutase by comparing the intra-and extracellular enzyme activity from Streptomyces subrutilus P5 and analyze possible genetic information for this enzyme secretion. The mycelial dry weights and glucose concentrations in culture filtrates were determined during growth. Glucose was consumed rapidly during logarithmic growth phase and almost exhausted at 24 h of cultivation. While the intracellular activity of iron containing superoxide dismutase was first appeared at three hours, the extracellular activity of this enzyme appeared from 7.5 h of cultivation, early logarithmic growth phase. This early presence of the superoxide dismutase might not be the result of cell lysis but active secretion pathway. There was no information for signal peptide responsible for the enzyme secretion in sodF. However, we found a type three secretion box in the promoter region of sodF that has been known for the genes of type III secreted proteins in other bacteria. This is the first report on the possible existence of type III secretion in Streptomyces.

• Korean Journal of Microbiology
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• v.39 no.4
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• pp.230-234
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• 2003

An extracellular protease 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 protease. The purified enzyme activity was inhibited by leucine peptidase inhibitor, bestatin, suggesting that the enzyme is a leucine endopeptidase. When the enzyme was chemically modified with PMSF, which specifically reacted with serine residue on the enzyme, the activity was eliminated. The endopeptidase activity was inhibited by the modifier which chemically modified carboxyl group of aspartate and glutamate. PLP, which would modify lysine residue, did not affect the endopepetidase activity to a greater extent. This demonstrates that serine and aspartate (or glutamate) residues of enzyme would participate in a important function of the endopeptidase activity.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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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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• v.19 no.10
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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.