• Asian-Australasian Journal of Animal Sciences
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• v.14 no.12
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• pp.1769-1774
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• 2001

Bacillus licheniformis strains L-25 and PWD-1 are two thermophilic feather-degrading bacteria. Despite isolated from different environmental conditions, they were both capable of breaking down chicken feathers and growing in a medium in which feather was the only source of carbon and nitrogen. A 1.46-kb keratinase gene (ker B) was isolated from strain L-25 by a polymerase chain reaction (PCR) using L-25 genomic DNA as templates. Sequencing results reveal that ker B shares great sequence identity with a previously published keratinase gene of B. licheniformis PWD-1 (ker A). Only two amino acids differences were found in the deduced amino acid sequence between the keratinases from L-25 and PWD-1. However several nucleotide changes were found upstream of the putative promoter region. Protease inhibition studies indicated that neutral protease activity accounted for approximate 25 to 30% of total extracellular proteolytic activity produced by strain L-25 in the feather medium. In contrast, no measurable neutral protease activity was produced by strain PWD-1 in the feather medium. When glucose (1%), a common catabolic repressor, was added into the feather medium, L-25 was still able to grow and produce keratinase. Strain PWD-1 produced no neutral protease activity and its growth was severely inhibited in the feather medium containing glucose. L-25 produced an enhanced level of keratinase in the feather medium in comparison with PWD-1.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.10
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• pp.672-678
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• 2014

In this study, variations of fermentative hydrogen production and microbial community were investigated with different nitrogen concentration of food waste. Optimum hydrogen production rate was acquired at 200 mg/L nitrogen concentration of the food waste. Which was eqivalent to 83.43 mL/g dry biomass/hr. However, bio-hydrogen production was inhibitedly reduced at over 600 mg/L of nitrogen concentration whereas proportional relation between hydrogen production and B/A ratio were not observed. Most dominant specie of the microbial community analyzed was Clostridium sp. throughout PCR-DGGE analysis of 16S rDNA. It revealed that most contributing microorganism producing hydrogen were Enterococcus faecium partial, Klebsiella pneumoniae strain ND6, Enterobacter sp. NCCP-231, and Clostridium algidicarnis strain E107 in this experiment.

• Journal of Microbiology and Biotechnology
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• v.29 no.5
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• pp.794-808
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• 2019

Bacillus velezensis strain WRN014 was isolated from banana fields in Hainan, China. Bacillus velezensis is an important member of the plant growth-promoting rhizobacteria (PGPR) which can enhance plant growth and control soil-borne disease. The complete genome of Bacillus velezensis WRN014 was sequenced by combining Illumina Hiseq 2500 system and Pacific Biosciences SMRT high-throughput sequencing technologies. Then, the genome of Bacillus velezensis WRN014, together with 45 other completed genome sequences of the Bacillus velezensis strains, were comparatively studied. The genome of Bacillus velezensis WRN014 was 4,063,541bp in length and contained 4,062 coding sequences, 9 genomic islands and 13 gene clusters. The results of comparative genomic analysis provide evidence that (i) The 46 Bacillus velezensis strains formed 2 obviously closely related clades in phylogenetic trees. (ii) The pangenome in this study is open and is increasing with the addition of new sequenced genomes. (iii) Analysis of single nucleotide polymorphisms (SNPs) revealed local diversification of the 46 Bacillus velezensis genomes. Surprisingly, SNPs were not evenly distributed throughout the whole genome. (iv) Analysis of gene clusters revealed that rich gene clusters spread over Bacillus velezensis strains and some gene clusters are conserved in different strains. This study reveals that the strain WRN014 and other Bacillus velezensis strains have potential to be used as PGPR and biopesticide.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.673-679
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• 2004

A microbial cryoprotectant formulation using a W/O/W multiple emulsion system was developed. The psychrotolerant microorganism, B4, isolated from soil in South Korea, was observed by the drop freezing method, in which the microorganism sample inhibited ice nucleation activity. The antifreeze activity was eliminated when the microorganism sample was treated with protease, indicating that the antifreeze activity was due to the presence of antifreeze protein. The result of the l6S rDNA sequencing indicated the B4 strain was most closely related to a species of the genus Bacillus. Culture broth of B4 strain (Bacillus sp.) and rapeseed oil containing 1 % polyglycerine polyricinolate (PGPR) were used as core and wall material, respectively. The most stable W/O emulsion was prepared at a core/oil ratio of 1:2. The highest W/O/W emulsion stability was achieved when the primary emulsion to external aqueous phase containing 0.5% caster oil polyoxyethylene ether $(COG25^{TM})$ ratio was 1:1. Microcrystalline cellulose showed better W/O/W emulsion stability than other polymer types. The viability of cells in a W/O/W emulsion was higher than free cells during storage at $37^\circ{C}$. An acidic pH and UV exposure decreased the viability of free cells, but cells in W/O/W emulsion were more stable under these conditions.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.761-767
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• 2022

EHT1 and EEB1 are the key Saccharomyces cerevisiae genes involved in the synthesis of ethyl esters during wine fermentation. We constructed single (Δeht1, Δeeb1) and double (Δeht1Δeeb1) heterogenous mutant strains of the industrial diploid wine yeast EC1118 by disrupting one allele of EHT1 and/or EEB1. In addition, the aromatic profile of wine produced during fermentation of simulated grape juice by these mutant strains was also analyzed. The expression levels of EHT1 and/or EEB1 in the relevant mutants were less than 50% of the wild-type strain when grown in YPD medium and simulated grape juice medium. Compared to the wild-type strain, all mutants produced lower amounts of ethyl esters in the fermented grape juice and also resulted in distinct ethyl ester profiles. ATF2, a gene involved in acetate ester synthesis, was expressed at higher levels in the EEB1 downregulation mutants compared to the wild-type and Δeht1 strains during fermentation, which was consistent with the content of acetate esters. In addition, the production of higher alcohols was also markedly affected by the decrease in EEB1 levels. Compared to EHT1, EEB1 downregulation had a greater impact on the production of acetate esters and higher alcohols, suggesting that controlling EEB1 expression could be an effective means to regulate the content of these aromatic metabolites in wine. Taken together, the synthesis of ethyl esters can be decreased by deleting one allele of EHT1 and EEB1 in the diploid EC1118 strain, which may modify the ester profile of wine more subtly compared to the complete deletion of target genes.

• Korean journal of applied entomology
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• v.35 no.1
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• pp.80-84
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• 1996

Infectivity of entomopathogenic nematodes and fungus was evaluated against fly larvae in the laboratory and outhouses. Mortalities of Muscina stabulans larvae were 96.7f 2.8% in Steinernema glaseri Dongrae strain, 90.0+0.0% in S. carpocapsae All strain, 86.7f 2.7% in Heterorhabditis bacteriophora Hamyang strain, and 70.0+9.4% in S. carpocapsae Pocheon strain on the filter paper. When 260, 000 nem\ulcornertodes were sprayed into the outhouses, H. bacterwphora Hamyang strain killed 100%, S. glaseri Dongrae strain killed 76.9+3.9%, and S. carpocapsae Pocheon strain killed 58.5+6.1% of maggots. When 130, 000 nematodes and 7.0X lo9 cfu of entomopathogenic fungus, Beauveria brongniartii were sprayed alone or combined into outhouses, mortalities of maggots were 73.6+0.1% in B. brongniartii alone, 77.8+3.9% in S. carpocapsae Pocheon strain plus B. brongniartii, and 77.7f 5.1% in H. bacteriophora Hamyang strain plus B. brongniartii. Entomopathogenic nematodes and fungus were potential biological control agents in this study.

• Proceedings of the Microbiological Society of Korea Conference
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• 2004.05a
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• pp.35-38
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• 2004

• Journal of Microbiology
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• v.43 no.1
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• pp.49-53
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• 2005

Putative genes for a two-component signal transduction system (akbS and akbT) were detected near the alkylbenzene-degrading operon of Rhodococcus sp. DK17. Sequence analysis indicates that AkbS possesses potential ATP-binding and histidine autophosphorylation sites in the N- and C-terminal regions, respectively, and that AkbT has a typical response regulator domain. Mutant analysis combined with RT-PCR experiments further shows that AkbS is required to induce the expression of o-xylene dioxygenase in DK17.

• Microbiology and Biotechnology Letters
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• v.19 no.6
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• pp.631-636
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• 1991

The bacteria which can biodegrade aromatic compounds were screened from soil and wastewater. The isolated Pseudomonas sp. HC107 had high removal rate of COD and phenol. And also this strain grew on m-cresol, salicylate, toluene, 2, 4-D and benzene. When the strain culture (2 ml/day) was treated on continuous reactor at mixed wastewater from chemical, pharmaceutical and dye industry, the treatment rate of COD, BOD and phenol was to be about 92.5%, 95.3% and 93.5%, respectively.

• Microbiology and Biotechnology Letters
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• v.4 no.3
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• pp.117-121
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• 1976

A microbial strain capable of degrading ABS (alkyl benzene sulfonate) was isolated and identified as Pseudomonas caryophylli. During the incubation of the isolated bacterium in a synthetic effluent containing 10 ppm of ABS, the extents of removal of ABS, BOD and COD were 40％, 89％ and 71％, respectively. The degradability of ABS by pure culture with the isolated strain was twice higher than that of mixed culture with natural microflora. The biodegradability of some commercial detergents in Korea by the isolated organism was as follows: Hiti 46.2％, Kleenup 37.5％, No.1 29％, and OK 27.9％.