• Asian-Australasian Journal of Animal Sciences
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• v.24 no.3
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• pp.379-385
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• 2011

Ferulic acid esterase (FAE) and acetyl esterase (AE) cleave feruloyl groups substituted at the 5'-OH group of arabinosyl residues and acetyl groups substituted at O-2/O-3 of the xylan backbone, respectively, of arabinoxylans in the cell wall of grasses. In this study, the enzyme profiles of FAE, AE and polysaccharide hydrolases of the anaerobic rumen fungus Neocallimastix sp. YQ1 grown on Chinese wildrye grass hay (CW) or alfalfa hay (AH) were investigated by two $2{\times}4$ factorial experiments, each in 10-day pure cultures. The treatments consisted of two glucose levels ($G^+$: glucose at 1.0 g/L, $G^-$: no glucose) and four N sources (N1: 1.0 g/L yeast extract, 1.0 g/L tryptone and 0.5 g/L $(NH_4)_2SO_4$; N2: 2.8 g/L yeast extract and 0.5 g/L $(NH_4)_2SO_4$; N3: 1.6 g/L tryptone and 0.5 g/L $(NH_4)_2SO_4$; N4: 1.4 g/L tryptone and 1.7 g/L yeast extract) in defined media. The optimal combinations of glucose level and N source for the fungus on CW, instead of AH, were $G^-N4$ and $G^-N3$ for maximum production of FAE and AE, respectively. Xylanase activity peaked on day 4 and day 6 for the fungus grown on CW and AH, respectively. The activities of esterases were positively correlated with those of xylanase and carboxymethyl cellulase. The fungus grown on CW exhibited a greater volatile fatty acid production than on AH with a greater release of ferulic acid from plant cell wall.

• Journal of Microbiology and Biotechnology
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• v.30 no.2
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• pp.155-162
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• 2020

Acetyl xylan esterase (AXE; E.C. 3.1.1.72) is one of the accessory enzymes for xylan degradation, which can remove the terminal acetate residues from xylan polymers. In this study, two genes encoding putative AXEs (LaAXE and BhAXE) were cloned from Lactobacillus antri DSM 16041 and Bacillus halodurans C-125, and constitutively expressed in Escherichia coli. They possess considerable activities towards various substrates such as p-nitrophenyl acetate, 4-methylumbelliferyl acetate, glucose pentaacetate, and 7-amino cephalosporanic acid. LaAXE and BhAXE showed the highest activities at pH 7.0 and 8.0 at 50℃, respectively. These enzymes are AXE members of carbohydrate esterase (CE) family 7 with the cephalosporine-C deacetylase activity for the production of antibiotics precursors. The simultaneous treatment of LaAXE with Thermotoga neapolitana β-xylanase showed 1.44-fold higher synergistic degradation of beechwood xylan than the single treatment of xylanase, whereas BhAXE showed no significant synergism. It was suggested that LaAXE can deacetylate beechwood xylan and enhance the successive accessibility of xylanase towards the resulting substrates. The novel LaAXE originated from a lactic acid bacterium will be utilized for the enzymatic production of D-xylose and xylooligosaccharides.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.11
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• pp.1576-1584
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• 2016

Acetyl xylan esterase (AXE), which hydrolyzes the ester linkages of the naturally acetylated xylan and thus known to have an important role for hemicellulose degradation, was isolated from the anaerobic rumen fungus Neocallimastix frontatlis PMA02, heterologously expressed in Escherichi coli (E.coli) and characterized. The full-length cDNA encoding NfAXE1 was 1,494 bp, of which 978 bp constituted an open reading frame. The estimated molecular weight of NfAXE1 was 36.5 kDa with 326 amino acid residues, and the calculated isoelectric point was 4.54. The secondary protein structure was predicted to consist of nine ${\alpha}$-helixes and 12 ${\beta}$-strands. The enzyme expressed in E.coli had the highest activity at $40^{\circ}C$ and pH 8. The purified recombinant NfAXE1 had a specific activity of 100.1 U/mg when p-nitrophenyl acetate (p-NA) was used as a substrate at $40^{\circ}C$, optimum temperature. The amount of liberated acetic acids were the highest and the lowest when p-NA and acetylated birchwood xylan were used as substrates, respectively. The amount of xylose released from acetylated birchwod xylan was increased by 1.4 fold when NfAXE1 was mixed with xylanase in a reaction cocktail, implying a synergistic effect of NfAXE1 with xylanase on hemicellulose degradation.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.153-156
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• 2000

Xylan, the major hemicellulose component of many plants, occurs naturally in a partially acetylated form and lignin, the most resistant component in plant cell wall degradation, is also attached to ${\beta}-1,4-linked-D-xylose$ backbone through the ester linkage. Esterases are required to release the esterified substituent and acetyl esterases are important in the complete degradation of acetylated polysaccharides, like pectins and xylans. The gene(Axe) encoding acetyl xylan estarase(AXE) was isolated from genomic ${\lambda}$ library from Aspergillus ficuum. Nucleotide sequencing of the Axe gene indicated that the gene was separated with two intervening sequences and the amino acid sequence comparison revealed that it was closely related to that from A. awamori with the 92 % indentity. Heterologous expression of AXE was conducted by using YEp352 and Saccharomyces cerevisae 2805 as a vector and host expression system, respectively. The Axe gene was placed between GAL1 promoter and GAL7 terminator and then this recombinant vector was used to transform S. cerevisiae 2805 strain. Culture filtrate of the transformed yeast was assayed for the presence of AXE activity by spectrophotometry and, comparing with the host strain, four to five times of enzyme activity was detected in culture filtrate of transformed yeast.

• Journal of the Korean Wood Science and Technology
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• v.25 no.2
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• pp.100-109
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• 1997

The objectives of this study was to decrease pollutions of bleaching effluent and was to enhanced brightness of non-chlorine bleached pulps by xylanase treatments. Xylanase cloned Esherichacoli(E. coli) capable of each of endo, exo-xylanase and acetyl-esterase were obtained from Bacillus stearothermophillus. These xylanase was maintained high activity in alkali and high temperature. Especially endo-xylanase would be more active in $60^{\circ}C$ and pH 11. Xylanase pretreatment(X) of unbleached pulp increased brightness, and decreased the degree of delignification. The degree of increase in brightness of pulp due to xylanase pretreatment was similar to non-enzyme treated pulp, regardless of the amount of enzyme added. Therefore, the addition of xylanase of 2 unit was recommended when considering costs of enzyme. The pulp bleached XO sequence had higher brightness and lower Kappa no, than O bleached pulp, while pulp bleached XP sequence had similar brightness and Kappa no. with P bleached pulp. In XOC/D, XOZ and XOP bleaching sequences, brightness and degree of delignification were improved. The C/D and Z stage bleached pulp was good effect on rate of raise in brightness and Kappa no., but P stage bleached pulp had similar level in non-enzyme treated bleaching sequence.

• Journal of fish pathology
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• v.27 no.1
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• pp.25-33
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• 2014

Hydrolase activities of excretory-secretory products (ESP) and somatic extracts (SE) from Anisakis simplex sensu stricto (s.s.) and Anisakis pegreffii larvae were investigated by using API ZYM kit. In esterase group, acid phosphatase showed high activity from both of A. simplex (s.s.) and A. pegreffii. Esterase (C4) showed activity only from SE and A. simplex (s.s.) showed higher activity than A. pegreffii. Alkaline phosphatase, acid phosphatase and naphthol-AS-BI-phosphohydrolase showed higher activity in 3rd stage larvae than in 4th stage larvae of both species. In aminopeptidase group, only leucine arylamidase showed remarkable activity in SE of both anisakid species, and A. simplex (s.s.) SE showed higher activity than A. pegreffii SE. In glycosidase group, N-acetyl-${\beta}$-glucosaminidase, ${\alpha}$-mannosidase, ${\alpha}$-fucosidase showed higher activity in A. simplex (s.s.) than A. pegreffii, and 4th larvae showed higher activity than 3rd larvae. These differences in hydrolase activity of anisakid nematodes larvae are thought to be due to different metabolism such as growth, moulting, digestion and feeding.

• Korean Journal of Microbiology
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• v.42 no.4
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• pp.257-264
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• 2006

Fifty eight Cryptococcus neoformans strains isolated from clinical and environmental sources in Korea were examined for their serotypes and extracellular enzyme activities. Among the 51 strains isolated from clinical sources, 48 strains were serotype A (94.1%), 2 strains were serotype B (3.92%), and 1 strain was serotype D (1.96%). All seven environmental strains isolated from pigeon excreta were identified as serotype A. All isolates of C. neoformtans were positive for the production of extracellular proteinase and phospholipase. In the API-ZYM system, all fifty eight isolates produced alkaine phosphatase, esterase C4, esterase lipase: C8, leucine arylamidase, acid phosphatase, naphthol-AS-BI-phosphohydrase, $\alpha$-glucosidase and $\beta$-glucosidase. Thirty nine isolates (67.2%) of C. neoformans produced N-acetyl-$\beta$-glucosidase. Two isolates, serotype B, and B only one serotype A produced $\beta$-glucuronidase. Analysis of enzymatic profiles to 21 enzymes revealed four biotypic patterns among the 58 strains. The enzymatic patterns of C. neoformans isolated from clinical and environmental sources represented a significant relationship with the serotypes.

• Journal of Life Science
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• v.23 no.12
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• pp.1420-1427
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• 2013

A novel acetylalginate esterase (AcAlgE) gene was previously cloned and characterized from Sphingomonas sp. MJ-3. In this study, the synergistic effects of MJ-3 AcAlgE, and KS-408 alginate lyase on the degradation of acetylalginate from Pseudomonas aeruginosa were investigated by using high-field 1H-NMR and an FPLC-equipped peptide column. The alginate lyase coupled assay of AcAlgE showed that degradation of high molecular weight acetylalginate was more difficult than degradation of acid hydrolyzed acetylalginate. The degradation of acetylalginate by alginate lyase was easier after AcAlgE was used to remove the acetyl group from acetylalginate. This result showed that the recombinant AcAlgE enhanced the degradation of acetylalginate by alginate lyase.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1203-1210
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• 2011

Function-driven metagenomic analysis is a powerful approach to screening for novel biocatalysts. In this study, we investigated lipolytic enzymes selected from an alluvial soil metagenomic library, and identified two novel esterases, EstDL26 and EstDL136. EstDL26 and EstDL136 reactivated chloramphenicol from its acetyl derivates by counteracting the chloramphenicol acetyltransferase (CAT) activity in Escherichia coli. These two enzymes showed only 27% identity in amino acid sequence to each other; however both preferentially hydrolyzed short-chain p-nitrophenyl esters (${\leq}C_5$) and showed mesophilic properties. In vitro, EstDL136 catalyzed the deacetylation of 1- and 3-acetyl and 1,3-diacetyl derivates; in contrast, EstDL26 was not capable of the deacetylation at $C_1$, indicating a potential regioselectivity. EstDL26 and EstDL136 were similar to microbial hormone-sensitive lipase (HSL), and since chloramphenicol acetate esterase (CAE) activity was detected from two other soil esterases in the HSL family, this suggests a distribution of CAE among the soil microorganisms. The isolation and characterization of EstDL26 and EstDL136 in this study may be helpful in understanding the diversity of CAE enzymes and their potential role in releasing active chloramphenicol in the producing bacteria.

• Journal of Microbiology and Biotechnology
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• v.16 no.6
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• pp.921-926
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• 2006

The production and location of xylanolytic enzymes in alkaliphilic Bacillus sp. K-1, isolated from the wastewater treatment plant of the pulp and paper industry, was studied. When grown in alkaline xylan medium, the bacteria produced xylanolytic enzymes such as xylanase, $\beta$-xylosidase, arabinofuranosidase, and acetyl esterase. Two types of xylanases (23 and 45 kDa) were found to be extracellular, but another type of xylanase (35 and/or 40 kDa) was detected as pellet-bound that was eluted with 2% triethylamine from the residual xylan of the culture. The xylanases were different in their molecular weight and xylan-binding ability. Arabinofuranosidase and $\beta$-xylosidase were found to be intracellular and extracellular, respectively, and acetyl esterase was found to be extracellular. The extracellular xylanolytic enzymes effectively hydrolyzed insoluble xylan, lignocellulosic materials, and xylans in kraft pulps.