• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.626-632
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• 2005

A new bacterium BL-2 excreting a novel cationic polyglucosamine biopolymer was isolated from the spoiled leaves of Chinese cabbage and identified as Enterobacter sp. BL-2. The isolated Enterobacter sp. BL-2 was cultivated in pH-stat fed-batch culture using acetic acid as the feeding stock at pH 8.0, resulting in 17.11 g/l of cells and 1.53 g/l of an extracellular biopolymer after 72 h. The excreted biopolymer was purified by a three-step procedure, involving ethanol precipitation and deproteinizations, to a nearly homogeneous state, and its molecular weight was found to be 106 kDa. It was composed of glucosamine, rhamnose, and galactose at a molar ratio of 86.4:1.6:1.0, respectively, indicating a rarely found novel high-glucosamine-containing biopolymer. The FT-IR and $^{13}C-NMR$ spectra of the novel cationic polyglucosamine biopolymer PGB-l revealed a close identity with chitosan from crab shell. It can effectively flocculate various suspended solids, including kaolin clay, $Ca(OH)_2,\;Al_{2}O_3$, active carbon, microbial cells, and acidic dyes.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.104-106
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• 2008

Enterobacter sp. BL-2 excretively produced a unique cationic polyglucosamine biopolymer PGB-1 comprised of more than 95% D-glucosamine in an acetate-mediated culture condition. The excretion of the biopolymer PGB-1 was closely associated with the cellular morphology of Enterobacter sp. BL-2, a feature highly dependable on the pH of the medium. The initially formed uneven and irregular surface cells were aggregated into the cell-biopolymer network structure connected by the adhesion modules of the cell-bound biopolymer. The excretive production of the biopolymer PGB-1 coincided with the disruption of the cell-biopolymer network, most actively at the medium pH of 8.0.

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.544-545
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• 2006

• Toxicological Research
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• v.23 no.1
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• pp.65-72
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• 2007

This study was conducted to obtain information of the oral dose acute toxicity of PGB-2, a novel polyglucosamine polymer produced from Citrobacter sp. BL-4 (a new strain) in male and female mice. Mortality, body weight changes, clinical signs were monitored during 14 days after single oral dose of test article at dose levels of 2000, 1000, 500, 250 and 125 ml/kg. Gross lesions, organ weight and histopathology of principal organs were examined after necropsy. As the results, we could not find any mortalities, clinical signs, changes in the body weight and gross findings except for white foci in the liver. In addition, no PGB-2-treatment related abnormal changes on the organ weight and histopathology of principle organs were detected except for atypical signs of liver. White liver foci were confirmed as focal infiltration of inflammatory cells. The results suggest that the PGB-2 is relatively safe in mice but the possibility of hepatotoxicity could not be excluded. The $LD_{50}$ and approximate LD in mice after single oral dose of PGB-2 were considered over 2000 mg/kg, respectively. In future, the potential hepatotoxicity of PGB-2 should be evaluated through the repeat dose toxicity test prior to develop as a new agent.

• Toxicological Research
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• v.23 no.4
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• pp.373-382
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• 2007

This study was conducted to obtain acute information of the oral dose toxicity of PGB-1, a novel polyglucosamine polymer produced from a new strain Enterobacter sp. BL-2 in male and female mice. In order to calculated 50% lethal dose ($LD_{50}$) and approximate lethal dose (LD), test material was once orally administered to male and female ICR mice at dose levels of 2000, 1000, 500, 250, 125 and 0 (vehicle control) ml/kg (body wt.). The mortality and changes on body weight, clinical signs, gross observation and organ weight and histopathology of principle organs were monitored 14 days after dosing with PGB-1. We could not find any mortalities, clinical signs, body weight changes and gross findings. In addition, significant changes in the organ weight and histopathology of principal organs were not observed except for some sporadic findings. The results obtained in this study suggest that PGB-1 may not be toxic in mice and may be therefore safe for clinical use. The $LD_{50}$ and approximate LD in mice after single oral dose of PGB-1 were considered over 2000 mg/kg in both female and male mice.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.175-175
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• 2003

Phthalocyanine, a water soluble porphyrin derivative and dye, is known to inhibit the mutagenic and carcinogenic actions of compounds having polycyclic structures, e.g. heterocyclic amines. There is evidence that this adsorbent effect shows by a complex formation between the porphyrin-like structure of phthalocyanine and the planar molecular surfaces of theses compounds. That phthalocyanine can form an insoluble material when mixed with chitosan, a polyglucosamine, and that the solid chitosan-phthalocyanine, named Eco-Blue, thus prepared can efficiently adsorb polycyclic mutagenic compounds. The adsorption was experimented by UV/VIS spectrometry. The adsorbent effects of mutagens and carcinogens was identified by Gas chromatography (GC) and Ames Test. The adsorbed polycyclic mutagens were elutable with buffer, but only to small extents. Chitosan-phthalocyanine may be expected to be useful as an adsorbent against polycyclic mutagens and carcinogens.