• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.212-217
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• 2004

The gene coding for mannanase from Bacillus subtilis WL-7, a number of glycosyl hydrolase family 26, was hyperexpressed in Escherichia coli. Two recombinant plasmids, pE7MAN and pENS7, were constructed by introducing the complete mannanase gene and the mature mannanase gene lacking N-terminal signal peptide region into a expression vector pET24a(＋), respectively. The level of mannanase produced by E. coli BL21 (DE3) carrying pENS7, which included the mature mannanase gene, was considerably higher than that by E. coli BL21 (DE3)/pE7MAN. Almost mannanase produced by the recombinant E. coli carrying pENS7 at growth temperature of $37^{\circ}C$ existed as inactive enzyme of insoluble form. Growth at temperature below $31^{\circ}C$ increased the soluble fraction of mannanase having catalytic activity in the recombinant E. coli cells. The highest productivity of active mannanase was observed in cell-free extract of the recombinant E. coli grown at growth temperature ranging from $25^{\circ}C$ to $28^{\circ}C$, while mannanase activity per soluble protein of the cell-free extract was highest in the cells grown at $^31{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.776-783
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• 2018

The agarase gene gaa16a was identified from a draft genome sequence of Gilvimarinus agarilyticus JEA5, an agar-utilizing marine bacterium. Recently, three agarase-producing bacteria, G. chinensis, G. polysaccharolyticus, and G. agarilyticus, in the genus Gilvimarinus were reported. However, there have been no reports of the molecular characteristics and biochemical properties of these agarases. In this study, we analyzed the molecular characteristics and biochemical properties of agarases in Gilvimarinus. Gaa16A comprised a 1,323-bp open reading frame encoding 441 amino acids. The predicted molecular mass and isoelectric point were 49 kDa and 4.9, respectively. The amino acid sequence of Gaa16A showed features typical of glycosyl hydrolase family 16 (GH16) ${\beta}$-agarases, including a GH16 domain, carbohydrate-binding region (RICIN domain), and signal peptide. Recombinant Gaa16A (excluding the signal peptide and carbohydrate-binding region, rGaa16A) was expressed as a fused protein with maltose-binding protein at its N-terminus in Escherichia coli. rGaa16A had maximum activity at $55^{\circ}C$ and pH 7.0 and 103 U/mg of specific activity in the presence of 2.5 mM $CaCl_2$. The enzyme hydrolyzed agarose to yield neoagarotetraose as the main product. This enzyme may be useful for industrial production of functional neoagaro-oligosaccharides.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.296-302
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• 2012

A bacterial strain was isolated from soybean paste fermented in a Korean Buddhist temple as a producer of the extracellular thermostable ${\alpha}$-amylase. The isolate YB-1234 has been identified as Bacillus licheniformis on the basis of its 16S rDNA sequence, morphology and biochemical properties. A gene encoding the thermostable ${\alpha}$-amylase of B. licheniformis YB-1234 was cloned into Escherichia coli and its nucleotide sequence was determined. The deduced amino acid sequence of ${\alpha}$-amylase was very highly homologous to those of the thermostable ${\alpha}$-amylases of B. licheniformis belonging to the glycosyl hydrolase family 13. The ${\alpha}$-amylase produced by recombinant E. coli carrying the ${\alpha}$-amylase gene exhibited maximal activity at pH 6.0, identical to ${\alpha}$-amylase in the culture filtrate of B. licheniformis, while the temperature profile was somewhat different between the two. Particularly, ${\alpha}$-amylase produced from B. lcheniformis is much more thermostable than that from recombinant E. coli. The predominant products resulting from the ${\alpha}$-amylase hydrolysis were glucose, maltose and maltotriose for maltotetraose and maltohexaose.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.141-146
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• 2012

A gene encoding the xylanase (XynA) predicted from partial genomic sequence of Paenibacillus woosongensis was cloned into Escherichia coli by PCR. This xynA gene consisted of 633 nucleotides, encoding a polypeptide of 211 amino acid residues. The deduced amino acid sequence exhibited 85-89% identity with those of several Paenibacillus xylanases, belonging to the glycosyl hydrolase family 11. As a results of expression of the structural gene by T7 promoter of a pET23a(+) expression vector, xylanase activity was higher in cell-free extract than culture filtrate of a recombinant Escherichia coli BL21(DE3) CodonPlus. However, the expression level of xylanase was not sufficient be detected by SDS-PAGE. The cell-free extract showed maximal xylanase activity at $60^{\circ}C$ and pH 5.5. The predominant products resulting from xylan and xylooligosaccharide hydrolysis were xylose and xylotriose. The enzyme could hydrolyze xylooligosaccharides larger than xylbiose.

• Journal of Microbiology and Biotechnology
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• v.23 no.7
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• pp.913-922
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• 2013

An agar-degrading bacterium was isolated from red seaweed (Gelidium amansii) on a natural seawater agar plate, and identified as Saccharophagus sp. AG21. The ${\beta}$-agarase gene from Saccharophagus sp. AG21 (agy1) was screened by long and accurate (LA)-PCR. The predicted sequence has a 1,908 bp open reading frame encoding 636 amino acids (aa), and includes a glycosyl hydrolase family 16 (GH16) ${\beta}$-agarase module and two carbohydrate binding modules of family 6 (CBM6). The deduced aa sequence showed 93.7% and 84.9% similarity to ${\beta}$-agarase of Saccharophagus degradans and Microbulbifer agarilyticus, respectively. The mature agy1 was cloned and overexpressed as a His-tagged recombinant ${\beta}$-agarase (rAgy1) in Escherichia coli, and had a predicted molecular mass of 69 kDa and an isoelectric point of 4.5. rAgy1 showed optimum activity at $55^{\circ}C$ and pH 7.6, and had a specific activity of 85 U/mg. The rAgy1 activity was enhanced by $FeSO_4$ (40%), KCl (34%), and NaCl (34%), compared with the control. The newly identified rAgy1 is a ${\beta}$-agarase, which acts to degrade agarose to neoagarotetraose (NA4) and neoagarohexaose (NA6) and may be useful for applications in the cosmetics, food, bioethanol, and reagent industries.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.327-333
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• 2014

Two genes encoding the mannanase of Bacillus sp. YB-1401 and B. amyloliquefaciens YB-1402, which had been isolated at acidic pH as mannanase producers, were each cloned into Escherichia coli, and sequenced. Both mannanase genes consisted of 1,080 nucleotides, encoding polypeptides of 360 amino acid residues. The deduced amino acid sequences of the two mannanase genes differed by four amino acid residues different, and were highly homologous to those of mannanases belonging to the glycosyl hydrolase family 26. Comparison of two mannanases produced from recombinant E. coli indicated that His-tagged mannanase of YB-1402 (HtMAN1402) was more stable than that of YB-1401 at acidic pH and high temperature. In particular, HtMAN1402 retained more than 50% of its activity at pH 3.0 after 4 h of pre-incubation, suggesting the enzyme is a valuable candidate for use as a feed additive. In addition, thermostability of the two mannanases was found to be enhanced by $Ca^{2+}$ ions.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.4
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• pp.64-73
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• 2008

The cDNA of CCF (coelomic cytolytic factor)-like gene (EC 3.2.1.16), a kind of glycosyl hydorlase, was isolated and cloned from the midgut of the earthworm Eisenia anderi. The size of nucleotide sequence appeared to be 1,152 bp and its predicted coding region was composed of 384 amino acid residues including the initiation methionine. The 17 residues at N-terminal end in the deduced amino acid sequence were regarded to be a signal peptide. Based on the amino acid sequence analysis, it appeared that this CCF-like protein could belong to glycosyl hydrolase family 16 (GHF16) and showed a high sequence homology of about 79~99% with CCF and CCF-like proteins from other earthworm species. The CCFs and CCF-like proteins from various earthworm species exhibited a 100% homology in the polysacchride-binding motif and glucanase motif. It has been reported that the CCFs isolated from E. fedita appeared to show a broader pattern recognition specificity than those from other earthworm species because this species resides in decaying organic matter showing very high microbial activity, implying that CCF-like protein isolated in this study from E. andrei might exhibit a broad substrate specificity that is a useful characteristic for industrial application. A phylogenetic analysis using the deduced amino acid sequences of CCF-related proteins through the BLASTX revealed that GHF16 families could be divided into three groups of metazoa, viriplantae and eubacteria subfamily. Subsequently the CCF-related proteins of metazoa subfamily could clearly be subgroup into lophotrochozoan and edysozoan type including a deuterostome origin. Further understanding of the biological properties of E. andrei CCF-like protein should be addressed to regulate the ${\beta}$-D-glucan hydrolysis and production for the industrial uses.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.3
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• pp.31-37
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• 2010

Chitinases (EC 3.2.1.14) hydrolyze the ${\beta}$-1,4-linkages in chitin, the second most abundant polymer of N-acetyl-${\beta}$-D-glucosamine which is a structural component of protective biological matrices such as fungal cell walls and insect exoskeletons. The glycosyl hydrolases 18 family including chitinases is an ancient gene family widely expressed in archea, prokaryotes and eukaryotes. Since earthworms live in the soil with a lot of microbial activities and fungi are supposed to be a major component of the diet of earthworm, it has been reported that there would be appropriate immune system to protect themselves from microorganisms attacks. In this study, the novel chitinase, EaChi, from the midgut of earthworm, Eisenia andrei, were identified and characterized. To obtain full-length cDNA sequence of chitinase, RT-PCR and RACE-PCR analyses were carried out by using the previously identified EST sequence amongst cDNA library established from the midgut of E. andrei. EaChi, a partial chitinase gene, was composed of 927 nucleotides encoding 309 amino acids. By the multiple sequence alignments of amino acids with other different species, it was revealed that EaCHI is a member of glycosyl hydrolases 18 family, which has two highly conserved domains, substrate binding and catalytic domain.

• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1688-1694
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• 2007

A gene encoding the mannanase of Bacillus subtilis WL-3, which had been isolated from Korean soybean paste, was cloned into Escherichia coli and the nucleotide sequence of a 2.7-kb DNA fragment containing the mannanase gene was subsequently determined. The mannanase gene, designated manA, consisted of 1,080 nucleotides encoding a polypeptide of 360 amino acid residues. The deduced amino acid sequence was highly homologous to those of mannanases belonging to glycosyl hydrolase family 26. The manA gene was strongly expressed in B. subtilis 168 by cloning the gene downstream of a strong B. subtilis promoter of plasmid $pJ27{\Delta}88U$. In flask cultures, the production of mannanase by recombinant B. subtilis 168 reached maximum levels of 300 units/ml and 450 units/ml in LB medium and LB medium containing 0.3% locust bean gum, respectively. Based on the zymogram ofthe mannanase, it was found that the mannanase produced by recombinant B. subtilis could be maintained stably without proteolytic degradation during the culture time.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.50.1-50.1
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• 2008