• Journal of Marine Bioscience and Biotechnology
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• v.10 no.1
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• pp.9-17
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• 2018

The aim of this study is to elucidate the biochemical properties of manno-oligosaccharides (MOS) hydrolyzed by extracellular enzyme of Bacillus N3. We strived to characterize the biochemical properties of MOS since N3 can effectively hydrolyzed natural polymannans such as galactomannan (GM) and konjac (glucomannan, KM), respectively. The hydrolysis of GM and KM was applied by the strain N3 in terms of reducing sugars and the highest production of reducing sugars was estimated to be about 750 mg/L and 370 mg/L respectively, which were quantified after 7 days of cultivation in the presence of both substrates. Hydrolysates derived from the hydrolysis of KM showed the significant antioxidant activity based on DPPH and ABTS radical scavenging activity with increasing of tyrosinase inhibitory activity. On the other hand, hydrolysates derived from the hydrolysis of GM showed only ABTS radical scavenging activity without showing significant changes on tyrosinase inhibitory activity. Our data suggest that those biological characteristics may be depend on the primary structure and the size of MOS, which may be useful as potent additives for diet foods.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.613-618
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• 2021

The quality characteristics of jelly-containing vinegar drinks were divided into three stages in this study. The jelly, which differs from the contents of the vinegar drink, sharply decreased the pH. After sterilization, hardness was significantly decreased, and the formulation was not maintained, which was considered the effect of low pH and high total acidity of vinegar drinks. Different experiments confirmed that pH and sterilization heating conditions were the major quality variables for gelation as both sodium citrate content and jelly hardness were correlated before and after sterilization. The hardness of the jelly, which differs in gel content, correlated with the increase in gelation content both before and after sterilization. Therefore, considering the spout jelly of a vinegar drink, pH of 3.5-3.7 and a content of glucomannan and caragenane mixed gel were considered appropriate to match the product's sensory properties.

• Journal of Applied Biological Chemistry
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• v.53 no.2
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• pp.71-76
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• 2010

A gene encoding the mannanase of Bacillus licheniformis WL-12, which had been isolated from Korean soybean paste, was cloned into Escherichia coli and nucleotide sequence of the mannanase gene was subsequently determined. The mannanase gene consisted of 1,080 nucleotides encoding a polypeptide of 360 amino acid residues. The deduced amino acid sequence was identical to that of putative mannanase from B. liceniformis DSM13 belonging to GH family 26. The mannanase was partially purified from cell-free extract of the recombinant Escherichia coli carrying a WL-12 mannanase gene by ammonium sulfate fractionation and DEAE-Sepharose column chromatography. Optimal conditions for the partially purified enzyme occurred at pH 6.0 and $65^{\circ}C$. The enzyme showed higher activity on locust bean gum (LBG) galactomannan and konjac glucomannan than on guar gum galactomannan. The predominant products resulting from the mannanase hydrolysis were mannose, mannobiose and mannotriose for LBG or mannooligosaccharides. The enzyme could hydrolyze mannooligosaccharides larger than mannobiose.

• Journal of Life Science
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• v.27 no.9
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• pp.1003-1010
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• 2017

An open reading frame coding for mannanase predicted from the partial genomic sequence of Paenibacillus woosongensis was cloned into Escherichia coli by polymerase chain reaction amplification, and completely sequenced. This mannanase gene, designated man26AT, consisted of 3,162 nucleotides encoding a polypeptide of 1,053 amino acid residues. Based on the deduced amino acid sequence, Man26AT was identified as a modular enzyme, which included a catalytic domain belonging to the glycosyl hydrolase family 26 and two carbohydrate-binding modules, CBM27 and CBM11. The amino acid sequence of Man26AT was homologous to that of several putative mannanases, with identity of 81% for P. ihumii and identity of less than 57% for other strains of Paenibacillus. A cell-free extract of recombinant E. coli carrying the man26AT gene showed maximal mannanase activity at $55^{\circ}C$ and pH 5.5. The enzyme retained above 80% of maximal activity after preincubation for 1 h at $50^{\circ}C$. Man26AT was comparably active on locust bean gum (LBG), galactomanan, and kojac glucomannan, whereas it did not exhibit activity on carboxymethylcellulose, xylan, or para-nitrophenyl-${\beta}$-mannopyranoside. The common end products liberated from mannooligosaccharides, including mannotriose, mannotetraose, mannopentaose, and mannohexaose, or LBG by Man26AT were mannose, mannobiose, and mannotriose. Mannooligosacchrides larger than mannotriose were found in enzymatic hydrolyzates of LBG and guar gum, respectively. However, Man26AT was unable to hydrolyze mannobiose. Man26AT was intracellularly degraded into at least three active proteins with different molecular masses by zymogram.

• Microbiology and Biotechnology Letters
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• v.42 no.2
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• pp.99-105
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• 2014

A Bacillus strain capable of hydrolyzing locust bean gum was isolated as a producer of extracellular mannanase by way of an enrichment culture in an acidic medium from homemade soybean pastes. The isolate YB-1401 showed a biochemical identity of 61.1% with Brevibacillus laterosporus, while the nucleotide sequence of its 16S rDNA had the highest similarity with that of Bacillus amyloliquefaciens. The mannanase productivity of the Bacillus sp. YB-1401 was drastically increased by mannans. Particularly, maximum mannanase productivity was reached at approximately 265 U/ml in LB medium supplemented with konjac glucomannan (4.0%). The mannanase was the most active at $55^{\circ}C$ and pH 5.5. Mannanase activity was completely maintained after pre-incubation at pH 3.5 to 11.0 for 1 h. The predominant products resulting from the mannanase hydrolysis were mannobiose and mannotriose for LBG, guar gum or mannooligosaccharides. A small amount of mannose was also detected in the hydrolyzates.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.4
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• pp.569-576
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• 2007

Four hundred and fifty tilapias ($6.77{\pm}0.23$ g) were assigned randomly to six groups to evaluate the feasibility of the tested antibacterial peptides (ABPs) and oligosaccharides as substitutes for antibiotics. The control group was fed with a commercial tilapia diet; other five groups were fed with the same commercial diet supplemented with konjac glucomannan (KGLM), cluster bean galactomannan (CBGAM), and three animal intestinal ABPs derived from chicken, pig and rabbit at 100 mg/kg respectively. After 21 days of feeding, growth, disease resistance, and in vivo anti-adherence were determined. Furthermore, the inhibitory effect of tested agents on adhesion of Aeromonas veronii biovar sobria (A.vbs) strain BJCP-5 to tilapia enteric epithelia in vitro was assessed by cell-ELISA system. As a result, the tested agents supplemented at 100 mg/kg show significant benefit to tilapia growth and disease resistance (p<0.05), and the benefit may be correlated with their interfering in the contact of bacteria with host mucosal surface. Although none of the tested agents did inhibit the growth of BJCP-5 in tryptic soy broth at $100{\mu}g/ml$, all of them did inhibit the adhesion of A.vbs to tilapia enteric epithelia in vivo and in vitro. In vitro mimic assays show that three ABPs at low concentrations of $25{\mu}g/ml$ and $2.5{\mu}g/ml$ have the reciprocal dose-dependent anti-adherence effect. The inhibition of ABPs may be correlated with a cation bridging and/or receptor-ligand binding, but not with hydrophobicity. The KGLM and CBGAM inhibited the adherence of BJCP-5 to tilapia enteric epithelia with dose-dependent manner in vitro, and this may be through altering bacterial hydrophobicity and interfering with receptor-ligand binding. Our results indicate that the anti-adherence of the tested ABPs and oligosaccharides may be one of the mechanisms in promoting tilapia growth and resistance to A.vbs.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.518-524
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• 2010

A mannanase gene (man26B) was obtained from a sea bacterium, Paenibacillus sp. BME-14, through the constructed genomic library and inverse PCR. The gene of man26B had an open reading frame of 1,428 bp that encoded a peptide of 475- amino acid residues with a calculated molecular mass of 53 kDa. Man26B possessed two domains, a carbohydrate binding module (CBM) belonging to family 6 and a family 26 catalytic domain (CD) of glycosyl hydrolases, which showed the highest homology to Cel44C of P. polymyxa (60% identity). The optimum pH and temperature for enzymatic activity of Man26B were 4.5 and $60^{\circ}C$, respectively. The activity of Man26B was not affected by $Mg^{2+}$ and $Co^{2+}$, but was inhibited by $Hg^{2+},\;Ca^{2+},\;Cu^{2+},\;Mn^{2+},\;K^+,\;Na^+$, and $\beta$-mercaptoethanol, and slightly enhanced by $Pb^{2+}$ and $Zn^{2+}$. EDTA did not affect the activity of Man26B, which indicates that it does not require divalent ions to function. Man26B showed a high specific activity for LBG and konjac glucomannan, with $K_m,\;V_{max}$, and $k_{cat}$ values of 3.80 mg/ml, 91.70 ${\mu}mol$/min/mg protein, and 77.08/s, respectively, being observed when LBG was the substrate. Furthermore, deletion of the CBM6 domain increased the enzyme stability while enabling it to retain 80% and 60% of its initial activity after treatment at $80^{\circ}C$ and $90^{\circ}C$ for 30 min, respectively. This finding will be useful in industrial applications of Man26B, because of the harsh circumstances associated with such processes.