• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2000.10a
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• pp.125-139
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• 2000

The differential enhanced degradation of cis- and trans-1,3-D was observed in the previous two studies performed by Ou et al. (1995) and especially Chung et al. (1999). This study was initiated to investigate the involvement of microorganisms in the differential enhanced degradation of the chemicals. As expected, microorganisms were responsible for the enhanced degradation of the chemicals. A mixed bacterial culture capable of degrading 1,3-D was isolated from an enhanced soil sample collected from a site treated with 1,3-D. Similar to the enhanced soil, the mixed culture degraded trans-1,3-D faster than cis-1,3-D. This mixed culture could not utilize cis- and trans-1,3-D as a sole source of carbon for growth. Rather, a variety of second substrates were evaluated to stimulate the differential enhanced degradation of the two isomers. As a result, the mixed culture degraded cis- and trans-1,3-D only in the presence of a suitable second substrate. Second substrates that had the capacity to stimulate the degradation included soil leachate, tryptone, tryptophan, and alanine. Other substrates tested, including soil extract, glucose, yeast extract, and indole (ailed to stimulate the degradation of the two isomers. Therefore, it appeared that the degradation of cis- and trans-1,3-D was a cometabolic process. The mixed culture was composed of four morphologically distinctive bacterial colonies.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.6
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• pp.797-802
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• 2001

Two strains of rumen fungi (Piromyces rhizinflata B157, Orpinomyces joyonii SG4) and three strains of rumen cellulolytic bacteria (Ruminococcus albus B199, Ruminococcus flavefaciens FD1 and Fibrobacter succinogenes S85) were used as mono-cultures or combinationally arranged as co- and sequential-cultures to assess the relative contributions and interactions between rumen fungi and cellulolytic bacteria on rice straw degradation. The rates of dry matter degradation of co-cultures were similar to those of corresponding bacterial mono-cultures. Compared to corresponding sequential-cultures, the degradation of rice straw was reduced in all co-cultures (P<0.01). Regardless of the microbial species, the cellulolytic bacteria seemed to inhibit the degradation of rice straw by rumen fungi. The high efficiency of fungal cellulolysis seems to affect bacterial degradation rates.

• Microbiology and Biotechnology Letters
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• v.22 no.2
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• pp.203-209
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• 1994

The bacterial strain which utilizes phenol and degrade TCE was isolated from an industrial waste site. The bacterial strain was named as T5-7 and identified as an Acinetobacter species. After phenol-induction, the strain T5-7 removed TCE efficiently without cell growth. So, it seems that TCE degradation was not related to cell growth. TCE degradation increased when initial cell concentrations of phenol-grown T5-7 were high. In the presence of phenol, initial degradation of TCE was delayed but total amount of degradation was not affected at final stage. The strain cultured in 0.1% yeast extract did not degrade TCE, which indicates that phenol induction was essential to the TCE degradation.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.146-155
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• 1983

Fundamental study was carried out to elucidate the mechanisms of biological degradation of dyestuff in environments. A few bacterial strains which were capable of degrading amarnath were obtained from soil through an extensive screening program and identified by microbiolological properties. Conditions for bacterial growth and amaranth degradation were characterized and optimized, and the degradation products were identified. The results were as follows. 1. The most active strain A12-1 to be capable of degradation of amaranth was identified as Pseudomonas sp. 2. Optimal conditions for growth of the strain A12-1 were:$35^{\circ}C$ and pH 7.5, and growth was markedly increaesd by aeration. 3. Degradation of amaranth by the strain was accessed under similiar conditions for growth, however significantly inhibited when the culture was aerated. 4. Both bacterial growth and amaranth degradation were gradually decreased with increased concentration of amaranth in the culture. 5. Reaction of the crude enzyme from the strain A12-1 was optimal at $35^{\circ}C$ and pH 7.5 for degrading amaranth. 6. Sodium naphthionate and R-amino salt were found to be the products of amaranth degradation by the strain A12-1.

• Journal of Microbiology and Biotechnology
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• v.30 no.9
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• pp.1355-1366
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• 2020

Sediment bacterial communities are critical to the biogeochemical cycle in river ecosystems, but our understanding of the relationship between sediment bacterial communities and their specific input streams in rivers remains insufficient. In this study, we analyzed the sediment bacterial community structure in a local river receiving discharge of urban domestic sewage by applying Illumina MiSeq high-throughput sequencing. The results showed that the bacterial communities of sediments samples of different pollution types had similar dominant phyla, mainly Proteobacteria, Actinobacteria, Chloroflexi and Firmicutes, but their relative abundances were different. Moreover, there were great differences at the genus level. For example, the genus Bacillus showed statistically significant differences in the hotel site. The clustering of bacterial communities at various sites and the dominant families (i.e., Nocardioidaceae, and Sphingomonadaceae) observed in the residential quarter differed from other sites. This result suggested that environmentally induced species sorting greatly influenced the sediment bacterial community composition. The bacterial co-occurrence patterns showed that the river bacteria had a nonrandom modular structure. Microbial taxonomy from the same module had strong ecological links (such as the nitrogenium cycle and degradation of organic pollutants). Additionally, PICRUSt metabolic inference analysis showed the most important function of river bacterial communities under the influence of different types of domestic sewage was metabolism (e.g., genes related to xenobiotic degradation predominated in residential quarter samples). In general, our results emphasize that the adaptive changes and interactions in the bacterial community structure of river sediment represent responses to different exogenous pollution sources.

• KSBB Journal
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• v.11 no.5
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• pp.524-528
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• 1996

Bacterial degradation of 4-chloro-2-methylphenoxyacetic acid (MCPA) was studied in column reactors under conditions approximating a fluidized bed system, with granular activated carbon (GAC) as a support matrix. A mixed bacterial culture of MCPA-degrading bacteria was used as an inoculum to develop a biofilm on GAC. Initially, adsorption of MCPA by GAC and blofilm formation on GAC were examined. MCPA degradation was evaluated with a batch and continuous mode of operation of the GAC fixed-film column reactors. In the batch operations, complete degradation of MCPA was achieved during the incubation period. Partial degradation of MCPA occurred in the continuous operations and MCPA degradation was dependent on the feeding rate of MCPA solution.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.964-968
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• 2002

Colon drug delivery is advantageous in the treatment of colonic disease and oral delivery of drugs unstable or suceptible to enzymatic degradation in upper GI tract. In this study, multilayer coated system that is resistant to gastric and small intestinal conditions but can be easily degraded by colonic bacterial enzymes was designed to achieve effective colon delivery of prednisolone. Variously coated tablets containing prednisolone were fabricated using chitosan and cellulose acetate phthalate (CAP) as coating materials. Release aspects of prednisolone in simulated gastrointestinal fluid and rat colonic extracts (CERM) were investigated. Also, colonic bacterial degradation study of chitosan was performed in CERM. From these results, a three layer (CAP/Chitosan/CAP) coated system exhibited gastric and small intestinal resistance to the release of prednisolone in vitro most effectively. The rapid increase of prednisolone in CERM was revealed as due to the degradation of the chitosan membrane by bacterial enzymes. The designed system could be used potentially used as a carrier for colon delivery of prednisolone by regulating drug release in stomach and the small intestine.

• Journal of Environmental Health Sciences
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• v.26 no.2
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• pp.59-66
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• 2000

Effects of carbon dioxide partial pressure(PCO2) on bacterial population, methane production rate and matter degradation in anaerobic digestion were investigated by using anaerobic chemostat type reactors at 35$\pm$1$^{\circ}C$, at the HRT of 7 days. At PCO2 of 0.5 atm, the specific methane production rate and specific substrate removal rate reached the maximum rates. The methane production rates in the reactors fed by mixed substrate were 26% higher than those obtained under the controlled condition. The number of acetate consuming methanogenic bacteria enumerated by the MPN(most probable number) method, decreased when PCO2 exceeded 0.7 atm. Hydrogen consuming methanogenic bacteria and homoacetogenic bacteria increased as PCO2 increased from 0.1 to 0.6 atm, however, decreased slightly at PCO2 above 0.7 atm. The number of hydrolytic bacteria, sulfate-reducing bacteria and H2-producing acetogenic bacterial were not much influenced by the change of PCO2. The potential methanogenic activity reached the maximum at PCO2 0.5 atm, however, decreased significantly when PCO2 exceeded 0.7 atm, would depend on free PCO2 concentration in solution.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.272-278
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• 1989

The bacteria utilizing 3-chlorobenzoate as a sole carbon and energy source were isolated by Most-Probable-Number technique and identified in Korean coastal waters. Pseudomonas, Moraxella and Flavobacterium were dominant genera and comprised 70.2% of total isolates. Forty-four biochemical, cultural, morphological and physiological testa were performed and average linding cluster analysis was conducted from the test results. Total 92.7% of isolates were clustered into 17 groups under the 80% similarity level. The degradation of 3-chlorobenzoate was performed by many heterogeneous bacteria and the species diversity of these bacterial group offers informations of the stability of bacterial communities in relation to carbon compound cycling in coastal enviromnents.

• Journal of the Korean Wood Science and Technology
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• v.25 no.3
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• pp.83-95
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• 1997

The degradation mode of lignocellulose by anaerobic ruminal cellulolytic bacterium Ruminococcus albus F-40 was investigated. Birchwood holocellulose and filter paper were incubated as the sole carbohydrate sources with using the Hungate techniques. After 2 or 4 days of incubation, samples were employed for chemical and electron microscopic evaluations. The degradation rate of cellulosic substrates and the adhesion rate of bacteria to the substrates increased proportionally with the decrease of relative crystallinity of cellulose, indicating the preferential breakdown of amorphous cellulose, by this bacterium. X-ray diffraction analyses and polarized light microscopy showed, however, that crystalline cellulose was also degraded by R. albus. FT-IR spectra indicated that not only cellulose but hemicellulose was also degraded by this bacterium. Electron microscopic investigations showed the protuberant structures on the surface of R. albus. These structures were much more significant when bacterial cells were grown in the media containing insoluble substrates, such as cellulose, indicating clearly that bacterial protuberant structures were induced by the substrates. Protuberant structures extended from the bacterial cells adhered tightly to the substrates and numerous vesicles covered the surface of cellulosic substrates affected. Cellulosome-like structures were distributed on the cellulose matrix. Electron microscopic works showed that diverse surface organells of R. albus were involved in the degradation of cellulosic materials. SEM examinations showed the breakdown of cellulose by R. albus was proceeded by severeal routes : short fiber formation, defibrillation and destrafication of cellulose microfibril.