• Microbiology and Biotechnology Letters
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• v.35 no.1
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• pp.11-16
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• 2007

The arylsulfatase gene (astA, 984 bp ORF) from Pseudoalteromonas carrageenovora genome was amplified by PCR and subcloned into the pHCE-IA vector, in which the hyper consitutive expression (HCE) promoter from the D-amino acid aminotransferase (D-AAT) gene of Geobacillus toevii was employed. The transformant cell, Escherichia coli BL21 (DE3)/pHCE-AST, on LB agar plate containig 4-methylumbelliferyl sulfate, showed an intense fluorescence at 360 nm, indicating that 4-methylumbelliferone was liberated by desulfatate activity. When BL21 (DE3)/pHCE-AST was grown on LB media containing 0.4% glucose or 0.4% glycerol, the arylsulfatase activity was higher at glycerol rather than at glucose. On 2% glycerol medium, the arylsulfatase activity reached 15.0 unit/ml, which was 2.6-fold higher expression level than that with 1% glycerol. The DNA ladder in agarose prepared from agar by this recombinant enzyme revealed similar resolution and migration patterns with a commercial agarose. This results suggests that arylsulfatase overexpressed in E. coli could be applicable to the economic production of electrophoretic-grade agarose.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.4
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• pp.257-265
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• 2009

The long-term effects of soil management history on microbial communities are still poorly understood. Our objectives were to determine the impact of long-term application of soil amendments on microbial communities in rice paddy fields. The treatments selected were control where crops were grown without any nutrient application (CON); nitrogen-phosphorus-potassium (NPK); NPK plus compost (CNPK); NPK plus lime (LNPK); and NPK plus silicate (WNPK). The long-term addition of organic and inorganic amendments significantly changed soil chemical properties. The amount of organic carbon increased in the treatments with fertilizer and amendments over that in the soil without inputs. However, we could not observe the differences of bacterial population among the treatments, but the number of aerobic bacteria increased by the addition of amendments. Isolates from the rice paddy soils before irrigation were Dactylosporangium, Ewingella, Geobacillus, Kocuria, Kurthia, Kytococcus, Lechevalieria, Micrococcus, Micromonospora, Paenibacillus, Pedobacter, Pseudomonas, Pseudoxanthomonas, Rhodococcus, Rothia, Sphingopyxis, Stenotrophomonas, and Variovorax. Dominant genera were Arthrobacter, Kocuria, Kurthia, and Bacillus in the long-term field. Microbial biomass was the highest in the compost treatment (CNPK), and was the lowest in the CON. Dehydrogenase activity in soils treated with rice compost straw was the highest and the activity showed an increasing trend according to treatment as follows: CON < WNPK < NPK = LNPK < CNPK. These results demonstrate that soil management practice, such as optimal application of fertilizer and amendment, that result in accumulations of organic carbon may increase microbial biomass and dehydrogenase activity in long-term rice paddy soils.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.1008-1012
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• 2003

Symbiobacterium toebii has been reported as a thermophile exhibiting a commensal interaction with Geobacillus toebii. The distribution of the commensal thermophiles in various soils was investigated using a denaturing gradient gel electrophoresis (DGGE). Based on the DGGE analysis, the enrichment condition for the growth of Symbiobacterium sp. was found to also enrich populations of several other microbial spp. as well as Symbiobacterium sp. In the enrichment experiment, several different 16S rDNA sequences of commensal thermophiles were detected in all of the soil samples tested, indicating that commensal thermophiles are widely distributed in various soils.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1579-1585
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• 2016

Sugar esters are valuable compounds composed of various sugars and fatty acids that can be used as antibacterial agents and emulsifiers in toothpaste and canned foods. For example, fructose fatty acid esters suppress growth of Streptococcus mutans, a typical pathogenic bacterium causing dental caries. In this study, fructose laurate ester was chosen as a target material and was synthesized by a transesterification reaction using Candida antarctica lipase B. We performed a solvent screening experiment and found that a t-butanol/dimethyl sulfoxide mixture was the best solvent to dissolve fructose and methyl laurate. Fructose laurate was synthesized by transesterification of fructose (100 mM) with methyl laurate (30 mM) in t-butanol containing 20% dimethyl sulfoxide. The conversion yield was about 90%, which was calculated based on the quantity of methyl laurate using high-performance liquid chromatography. Fructose monolaurate (M_r 361) was detected in the reaction mixture by high-resolution mass spectrometry. The inhibitory effect of fructose laurate on growth of oral or food spoilage microorganisms, including S. mutans, Bacillus coagulans, and Geobacillus stearothermophilus, was evaluated.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.481-489
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• 2007

[ $\alpha$ ]-L-Arabinofuranosidases (AFases; EC 3.2.1.55) are exo-type enzymes, which hydrolyze terminal nonreducing arabinose residues from various polysaccharides such as arabinan and arabinoxylan. Genome-wide BLAST search showed that various bacterial strains possess the putative AFase genes with well-conserved motif sequences at the nucleotide and amino acid sequence levels. In this study, two sets of degenerate PCR primers were designed and tested to detect putative AFase genes, based on their three highly conserved amino acid blocks (PGGNFV, GNEMDG; and DEWNVW). Among 20 Bacillus-associated species, 13 species were revealed to have putative AFase genes in their genome and they share over 67% of amino acid identities with each other. Based on the partial sequence obtained from an isolate, an AFase from Geobacillus sp. was cloned and expressed in E. coli. Enzymatic characterization has verified that the resulting enzyme corresponds to a typical AFase. Accordingly, degenerate PCR primers developed in this work can be used for fast, easy, and specific detection and isolation of putative AFase genes from bacterial cells.

• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.305-313
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• 2018

A microbial consortium, TMC7, was enriched for the degradation of natural lignocellulosic materials under high temperature. TMC7 degraded 79.7% of rice straw during 15 days of incubation at $65^{\circ}C$. Extracellular xylanase was effectively secreted and hemicellulose was mainly degraded in the early stage (first 3 days), whereas primary decomposition of cellulose was observed as of day 3. The optimal temperature and initial pH for extracellular xylanase activity and lignocellulose degradation were $65^{\circ}C$ and between 7.0 and 9.0, respectively. Extracellular xylanase activity was maintained above 80% and 85% over a wide range of temperature ($50-75^{\circ}C$) and pH values (6.0-11.0), respectively. Clostridium likely had the largest contribution to lignocellulose conversion in TMC7 initially, and Geobacillus, Aeribacillus, and Thermoanaerobacterium might have also been involved in the later phase. These results demonstrate the potential practical application of TMC7 for lignocellulosic biomass utilization in the biotechnological industry under hot and alkaline conditions.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.662-671
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• 2015

To enrich the genetic resource of microbial xylanases with high activity and stability under alkaline conditions, a xylanase gene (xynSL4) was cloned from Planococcus sp. SL4, an alkaline xylanase-producing strain isolated from the sediment of soda lake Dabusu. Deduced XynSL4 consists of a putative signal peptide of 29 residues and a catalytic domain (30-380 residues) of glycosyl hydrolase family 10, and shares the highest identity of 77% with a hypothetical protein from Planomicrobium glaciei CHR43. Phylogenetic analysis indicated that deduced XynSL4 is closely related with thermophilic and alkaline xylanases from Geobacillus and Bacillus species. The gene xynSL4 was expressed heterologously in Escherichia coli and the recombinant enzyme showed some superior properties. Purified recombinant XynSL4 (rXynSL4) was highly active and stable over the neutral and alkaline pH range from 6 to 11, with maximum activity at pH 7 and more than 60% activity at pH 11. It had an apparent temperature optimum of 70℃ and retained stable at this temperature in the presence of substrate. rXynSL4 was highly halotolerant, retaining more than 55% activity with 0.25-3.0 M NaCl and was stable at the concentration of NaCl up to 4M. The enzyme activity was significantly enhanced by β-mercaptoethanol and Ca²⁺ but strongly inhibited by heavy-metal ions and SDS. This thermophilic and alkaline- and salt-tolerant enzyme has great potential for basic research and industrial applications.

• Journal of Environmental Health Sciences
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• v.39 no.3
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• pp.279-288
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• 2013

Objectives: Effectiveness and conditions of vapor-phase hydrogen peroxide (VPHP) system on decontamination of Geobacillus stearothermophilus(GS) spores, Escherichia coli (E.coli) and Enterobacteria phage felix01 (felix01) were determined. Methods: The VPHP system was designed to vaporize 35% (w/w) solution of hydrogen peroxide, continuously to inject and withdraw VPHP. The system and VHP 1000ED (Steris) were operated such that dehumidification and conditioning were initiated without samples in the chamber. Then the samples were loaded into and removed. Coupons (glass, anodizing, silicon, viton) with GS spores ($1{\times}10^6$ colony forming unit/mL [CFU/mL]), E.coli ($1{\times}10^7$ CFU/mL) and felix01 ($1{\times}10^7$ plaque forming unit/mL[PFU/mL]), and Biological Indicator (BI) with GS spores ($1{\times}10^6$ CFU/mL) on stainless steel coupons were used. The tested samples were sonicated and vortexed, and then were plated for enumeration, followed by incubation at $55^{\circ}C$, 24 hr for GS spores, and at $37^{\circ}C$, 24 hr for E.coli and felix01. BI analysis in broth culture was only qualitative. Results: The efficacy of the VPHP system on decontamination was almost equivalent to that of VHP 1000ED. The conditions for complete decontamination with the VPHP system was as follows: concentration; 700~450 ppm, relative humidity; approximately 55%, and temperature; $34{\sim}32^{\circ}C$. When comparing the decontamination efficiency among different kinds of coupons, glass was the most effective, however, all kinds of coupons were decontaminated completely after 60 min exposure in both systems. Conclusion: The VPHP system can be recommended as an alternative system for traditional system using ethylene oxide, formaldehyde or chlorine dioxide.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.995-1000
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• 2010

A novel deoC gene was identified from Paenibacillus sp. EA001 isolated from soil. The gene had an open reading frame (ORF) of 663 base pairs encoding a protein of 220 amino acids with a molecular mass of 24.5 kDa. The amino acid sequence was 79% identical to that of deoxyribose 5-phosphate aldolase (DERA) from Geobacillus sp. Y412MC10. The deoC gene encoding DERA was cloned into an expression vector and the protein was expressed in Escherichia coli. The recombinant DERA was purified using Ni-NTA affinity chromatography and then characterized. The optimum temperature and pH of the enzyme were $50^{\circ}C$ and 6.0, respectively. The specific activity for the substrate deoxyribose 5-phosphate (DR5P) was $62\;{\mu}mol/min/mg$. The $K_m$ value for DR5P was determined to be 145 mM with the $k_{cat}$ value of $3.2{\times}10^2/s$ from Lineweaver-Burk plots. The EA001 DERA showed stability toward a high concentration of acetaldehyde (100 mM).

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.585-591
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• 2014

To evaluate the potential utility of pretreatment of raw biomass with a complex microbial system, we investigated the degradation of rice straw by BMC-9, a lignocellulose decomposition strain obtained from a biogas slurry compost environment. The degradation characteristics and corresponding changes in the bacterial community were assessed. The results showed that rapid degradation occurred from day 0 to day 9, with a peak total biomass bacterium concentration of $3.3{\times}10^8$ copies/ml on day 1. The pH of the fermentation broth declined initially and then increased, and the mass of rice straw decreased steadily. The highest concentrations of volatile fatty acid contents (0.291 mg/l lactic acid, 0.31 mg/l formic acid, 1.93 mg/l acetic acid, and 0.73 mg/l propionic acid) as well as the highest xylanse activity (1.79 U/ml) and carboxymethyl cellulase activity (0.37 U/ml) occurred on day 9. The greatest diversity among the microbial community also occurred on day 9, with the presence of bacteria belonging to Clostridium sp., Bacillus sp., and Geobacillus sp. Together, our results indicate that BMC-9 has a strong ability to rapidly degrade the lignocelluloses of rice straw under relatively inexpensive conditions, and the optimum fermentation time is 9 days.