• Journal of Microbiology and Biotechnology
• /
• v.14 no.5
• /
• pp.938-943
• /
• 2004

A gene responsible for the chlorothalonil-biotransformation was cloned from the chromosomal DNA of Ochrobactrum anthropi SH35B, an isolated bacterium strain from soil. We determined the nucleotide sequences and found an open reading frame for glutathione S-transferase (GST). The drug-hypersensitive Escherichia coli KAM3 cells transformed with a plasmid carrying the GST gene can grow in the presence of chlorothalonil. The GST of O. anthropi SH35B was expressed in E. coli and purified by affinity chromatography. The fungicide chlorothalonil was rapidly transformed by the purified GST in the presence of glutathione. No significant difference in the chlorothalonil-biotransformation effect was observed among the thiol compounds (cysteine, reduced glutathione, and $\beta$-mercaptoethanol). Thus, the result reported here is the first evidence on the chlorothalonil-biotransformation by conjugation with the cellular free thiol groups, especially glutathione, catalyzed by the bacterial GST.

• 한국생물공학회:학술대회논문집
• /
• 2003.10a
• /
• pp.764-764
• /
• 2003

• 한국생물공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.475-475
• /
• 2005

• Proceedings of the Korean Society of Grassland Science Conference
• /
• 2001.06a
• /
• pp.89.1-89
• /
• 2001

• Journal of Microbiology and Biotechnology
• /
• v.14 no.3
• /
• pp.639-642
• /
• 2004

The pH as a control parameter for oxidation-reduction potential (ORP) was investigated through the denitrification by Ochrobactrum anthropi SY509 under non-growing condition. The optimal pH of nitrate reductase was 7.0, and the minimal ORP level was －250 mV for the denitrification under aerobic condition. In the case of anaerobic condition, the optimal pHs of nitrate and nitrite reductase were shifted to 10.0 and 9.0, respectively, and the minimal ORP levels of nitrate and nitrite reductase were decreased to －370 mV and －340mV, respectively. In the case of alkaline pH and anaerobic condition, the denitrification efficiency of nitrate was increased up to about 2-fold over that of neutral pH and anaerobic condition. Therefore, the combined control of pH and ORP in the anaerobic condition is shown to be an important parameter in the biological denitrification process.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.5
• /
• pp.678-682
• /
• 2006

To remove nitrate from wastewater, a novel bioelectrochemical denitrification system is introduced. In this proposed system, biological reactions are coupled with reactions on the electrode, whereby the electrons are transferred to the bacterial enzymes via a mediator as an electron carrier. The denitrification reaction was achieved with permeabilized Ochrobactrum anthropi SY509 containing denitrifying enzymes, such as nitrate reductase, nitrite reductase, and nitrous oxide reductase, and methyl viologen was used as the mediator. The electron transfer from the electrode to the enzymes in the bacterial cells was confirmed using cyclic voltammetry. A high removal efficiency of nitrate was achieved when the bioelectrochemical system was used with the permeabilized cells. Furthermore, when the permeabilized cells were immobilized to a graphite felt electrode using a calcium alginate matrix containing graphite powder, a high removal efficiency was achieved (4.38 nmol/min mg cell) that was comparable to the result when using the free permeabilized cells.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.11
• /
• pp.1803-1808
• /
• 2008

For practical application, the stability of permeabilized Ochrobactrum anthropi SY509 needs to be increased, as its half-life of enzymatic denitrification is only 90 days. As the cells become viable after permeabilization treatment, this can cause decreased activity in a long-term operation and induce breakage of the immobilization matrix. However, the organic solvent concentration causing zero cell viability was 50%, which is too high for industrial application. Thus, whole-cell immobilization using glutaraldehyde was performed, and 0.1% (v/v) glutaraldehyde was determined as the optimum concentration to maintain activity and increase the half-life. It was also found that 0.1% (v/v) glutaraldehyde reacted with 41.9% of the total amine residues on the surface of the cells during the treatment. As a result, the half-life of the permeabilized cells was increased from 90 to 210 days by glutaraldehyde treatment after permeabilization, and no cell viability was detected.

• Journal of Microbiology
• /
• v.41 no.3
• /
• pp.183-188
• /
• 2003

We isolated and cultured bacteria that inhabited marine biofilms, and identified them by phylogenetic analysis using 16S rDNA sequences. In the marine environment, biofilms cover most subtidal and intertidal solid surfaces such as rocks, ships, loops, marine animals, and algae. The bacteria in most biofilms are embedded in extracellular polymeric substances that comprise mainly of exopolysaccharides. The exopolysaccharides are excreted from multiple bacterial species; therefore, biofilms are a good source for screening exopolysaccharide-producing bacteria. Thirty-one strains were cultured, and a total of 17 unique strains were identified. Phylogenetic analysis using 16S rDNA sequences indicated that the 17 strains belonged to ${\alpha}$-Proteobacteria (Ochrobactrum anthropi, Paracoccus carotinifaciens); ${\gamma}$-Proteobacteria (Pseudoalteromonas agarovorans, P. piscicida, Pseudomonas aeruginosa, Shewanella baltica, Vibrio parahaemolyticus, V. pomeroyi); CFB group bacteria (Cytophaga latercula, Tenacibaculum mesophilum); high GC, Gram-positive bacteria (Arthrobacter nicotianae, Brevibacterium casei, B. epidermidis, Tsukamurella inchonensis); and low GC, Gram-positive bacteria (Bacillus macroides, Staphylococcus haemolyticus, S. warneri).

• Korean Journal of Veterinary Research
• /
• v.50 no.2
• /
• pp.125-131
• /
• 2010

Bacterial contamination is an unavoidable finding of the semen collection process in boar and can lead in deleterious effects on semen quality and longevity if left uncontrolled. The purpose of this study is to identify the bacteria in extended boar semen and to select the effective antimicrobials to control of the contaminants. Of 116 extended boar semen samples submitted from eight AI centers in Korea, 39 (33.6%) samples were positive for bacterial contamination. Among 39 contaminated semen, most of them (84.6%) were contaminated with one or two bacterial species and there was no significant difference between two age groups $(\leq\;24\;and\;>\;24\;month\;old).$ Stenotrophomonas maltophilia (n = 18) was the most predominant bacterium followed by Elizabethkingia meningoseptica (n = 12), Sphingomonas paucimobilis (n = 12), Myroides spp. (n = 5), Ochrobactrum anthropi (n = 3), and so on. Enrofloxacin (72.9%), florfenicol (72.9%), bacitracin (49.2%) and tylosin (49.2%) showed higher sensitivity compared with penicillin (13.6%) or aminoglycosides (6.8%-18.6%). Brucella spp., Leptospira spp., Mycoplasma hyopneumoniae, Mycoplasma hyorhinis, Mycobacterium tuberculosis complex were not detected in semen by PCR.