• 한국토양동물학회지
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• 제3권1호
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• pp.19-24
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• 1998

The importance of the gut microorganism in the termite, Reticulitermes Speratus kyushuenesis Morimoto, was estimated by feeding with several antibiotics. Antibiotics which killed the bacterium, but not the fungi (Ampicillin, Kanamycin, Erythromycin), or killed both the microorganismw (Cephaloridine, Tetracycline) reduced the life span of the termite from 245 days to about 15 days. On the other hand, some antibiotics, penicillin and pimaricin, did not greatly reduce the life span of the termite.

• Mycobiology
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• 제48권6호
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• pp.501-511
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• 2020

Xylophagous termites are capable of degrading lignocellulose by symbiotic gut microorganisms along with the host's indigenous enzymes. Therefore, the termite gut might be a potential niche to obtain natural yeasts with celluloytic, xylanolytic and ethanologenic traits required for bioethanol production from lignocellulosic biomass. In this study, we cultured 79 yeasts from three different termites viz. Coptotermes heimi, Odontotermes javanicus and Odontotermes obesus. After suitable screening methods, we identified 53 yeasts, which belonged to 10 genera and 16 different species of both ascomycetous and basidiomycetous yeasts. Most yeasts in the present study represent their first-ever isolation from the termite gut. Representative strains of identified yeasts were evaluated for their cellulolytic, xylanolytic, and ethanologenic abilities. None of the isolates showed cellulase activity; 22 showed xylanolytic activity, while six produced substantial quantities of ethanol. Among xylanolytic cultures, Pseudozyma hubeiensis STAG 1.7 and Hannaella pagnoccae STAG 1.14 produced 1.31 and 1.17 IU of xylanase. Among ethanologenic yeasts, the strains belonging to genera Candida and Kodamaea produced high amount of ethanol. Overall, highest ethanol level of 4.42 g/L was produced by Candida tropicalis TS32 using 1% glucose, which increased up to 22.92 g/L at 35 ℃, pH 4.5 with 5% glucose. Fermentation of rice straw hydrolysate gave 8.95 g/l of ethanol with a yield of 0.42 g/g using the strain TS32. Our study highlights the gut of wood-feeding termites as a potential source of diverse yeasts that would be useful in the production of xylanase and bioethanol.

• Journal of the Korean Wood Science and Technology
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• 제46권6호
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• pp.713-725
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• 2018

Lower termites require symbiotic microbes in their gut. The microbial communities in the termites must adapt to the termite temperature. Reticulitermes speratus KMT001 from Bukhan Mountain in Seoul may require a special symbiotic microorganisms for growth in low temperature Korean habitat. A metagenomics analysis showed a dramatic change in the symbiotic bacterial flora in the gut of R. speratus KMT001 in response to low temperatures of $4^{\circ}C$ or $10^{\circ}C$. Elusimicrobia, which are endosymbionts of flagellate protists, is the dominant phylum in the termite gut at ${\geq}15^{\circ}C$ but its population decreased drastically at low temperature. Four representative bacterial strains isolated from R. speratus KMT001 in a previous study produced maximum ${\beta}$-glucosidase levels within the temperature range of $10^{\circ}C-30^{\circ}C$. Elizabethkingia sp. BM10 produced ${\beta}$-glucosidase specifically at $10^{\circ}C$. This strain supported the existence of symbiotic bacteria for the low temperature habitat of the termite. This identified bacterium will be a resource for studying low temperature adaptation of termites, studying the gene expression at low temperatures, and developing an industrial cellulase at low temperature.

• Journal of Microbiology and Biotechnology
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• 제22권4호
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• pp.462-469
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• 2012

A metagenomic fosmid library was constructed from genomic DNA isolated from the microbial community residing in hindguts of a wood-feeding higher termite (Microcerotermes sp.) collected in Thailand. The library was screened for clones expressing lignocellulolytic activities. Fourteen independent active clones (2 cellulases and 12 xylanases) were obtained by functional screening at pH 10.0. Analysis of shotgun-cloning and pyrosequencing data revealed six ORFs, which shared less than 59% identity and 73% similarity of their amino acid sequences with known cellulases and xylanases. Conserved domain analysis of these ORFs revealed a cellulase belonging to the glycoside hydrolase family 5, whereas the other five xylanases showed significant identity to diverse families including families 8, 10, and 11. Interestingly, one fosmid clone was isolated carrying three contiguous xylanase genes that may comprise a xylanosome operon. The enzymes with the highest activities at alkaline pH from the initial activity screening were characterized biochemically. These enzymes showed a broad range of enzyme activities from pH 5.0 to 10.0, with pH optimal of 8.0 retaining more than 70% of their respective activities at pH 9.0. The optimal temperatures of these enzymes ranged from $50^{\circ}C$ to $55^{\circ}C$. This study provides evidence for the diversity and function of lignocellulose-degrading enzymes in the termite gut microbial community, which could be of potential use for industrial processes such as pulp biobleaching and denim biostoning.

• 한국토양동물학회지
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• 제3권2호
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• pp.51-57
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• 1998

A new rod-shaped endospore-forming bacterium isolated from the hindgut flora of the termite, Reticulitermes speratus kyushuenesis Morimoto is described. The isolate stained Gram positive, but the KOH test and the test for L-alanine aminopeptidase were negative. The length of a single cell varies from 2.5-9.0 $\mu $m, and the cell is about 0.5-0.7$\mu $m thick. The isolate had a high cellulolytic ability and was identified as Bacillus amyloliquefaciens.

• Journal of Microbiology and Biotechnology
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• 제27권1호
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• pp.122-129
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• 2017

Termites are destructive to agriculture, forestry, and buildings, but they can also promote agro-ecosystem balance through the degradation of lignocellulose. Termite-triggered cellulose digestion may be clarified through microbial metabolism of cellulose products. In the present study, we characterized the activities of cellulase and its three components synthesized by the cellulase-producing fungal strain HDZK-BYTF620 isolated from the gut of Odontotermes formosanus. The protein components of cellulases were synthesized by strain HDZK-BYTF620, which were isolated and characterized using polyacrylamide gel electrophoresis, and the expression of the cellulases was studied at the proteome level.

• BMB Reports
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• 제44권1호
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• pp.52-57
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• 2011

Termites play an important role in the degradation of dead plant materials and have acquired endogenous and symbiotic cellulose digestion capabilities. The feruloyl esterase enzyme (FAE) gene amplified from the metagenomic DNA of Coptotermes formosanus gut was cloned in the TA cloning vector and subcloned into a pET32a expression vector. The Ft3-7 gene has 84% sequence identity with Clostridium saccharolyticum and shows amino acid sequence identity with predicted xylanase/chitin deacetylase and endo-1,4-beta-xylanase. The sequence analysis reveals that probably Ft3-7 could be a new gene and that its molecular mass was 18.5 kDa. The activity of the recombinant enzyme (Ft3-7) produced in Escherichia coli (E.coli) was 21.4 U with substrate ethyl ferulate and its specific activity was 24.6 U/mg protein. The optimum pH and temperature for enzyme activity were 7.0 and $37^{\circ}C$, respectively. The substrate utilization preferences and sequence similarity of the Ft3-7 place it in the type-D sub-class of FAE.