• Korean Journal of Microbiology
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• v.48 no.1
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• pp.48-51
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• 2012

A novel Chryseobacterium sp. JK1 strain producing extracellular protease had been isolated from soil. The largest clear zones were observed on nutrient agar plates supplemented with 1% skim milk at $30-35^{\circ}C$ along with the growth of Chryseobacterium sp. JK1. The cell growth of JK1 strain was maximal at 24 h and maximum protease activity was reached up to 560 unit/ml at the stationary phase in liquid culture. In the presence of maltose, glucose or mannitol in Nutrient broth, cells grew well, but protease were produced poorly with lower production yields of 64-77% than in NB broth only. Similarly, the addition of skim milk, beef extract, yeast extract, malt extract or tryptone showed good growth and poor enzyme production. On the contrary, the addition of $(NH_4)_2HPO_4$ or $(NH_4)_2SO_4$ gave poor growth and good enzyme production of 121-146%.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.86-92
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• 2010

Thirty-one chicken feather-degrading bacteria were isolated from wasted feather, compost and wastewater in a chicken farm. These isolates were categorized as Firmicutes (21 strains), ${\gamma}$-proteobacteria (4 strains), Actinobacteria (4 strains), and Bacteroidetes (2 strains) by 16S rRNA gene sequence analysis. We examined the feather-degrading isolates for degradation in the 2% of chicken feather meal. The strain Chryseobacterium sp. FBF-7, Stenotrophomonas maltophilia FBS-4, and Lysinibacillus sp. FBW-3 were selected as a keratinolytic protein degrading bacteria which showed the highest feather degradation of 75-90%. The characteristics of amino acids extracted from chicken feather meal by using keratinolytic protein degrading isolates and chemical method with $Ca(OH)_2$ were analyzed. Total amino acid content of strain Chryseobacterium sp. FBF-7 was 1,661.6 ${\mu}mol$/ml, which was the highest and it was similar with chemical method. And essential amino acid content of total amino acid was thirty-seven percent (619.3 ${\mu}mol$/ml) and 596.9 ${\mu}mol$/ml for keratinolytic protein degrading isolates and chemical method, respectively. The major amino acids were valine, glutamic acid, aspartic acid, glycine, and proline by the strain Chryseobacterium sp. FBF-7 and especially, higher contents of aspartic acid, threonine, serine, cysteine, and tyrosine were detected compared with chemical method.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.78-82
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• 2013

A novel Chryseobacterium sp. JK1 strain isolated from soil had been reported that this isolate produced large amount of extracellular protease at mesophilic temperature in previous study. The optimal temperature and pH of extracellular protease were $40^{\circ}C$ and 7.0, respectively, showing narrow range of optimal temperature and relatively broad activity from pH 6.0 to 9.0. In addition, the protease showed greatest activity against skim milk and lowest against bovine serum albumin (BSA). The protease strongly inhibited by ethylenediaminetetraacetic acid (EDTA), ethylene glycol tetraacetic acid (EGTA) or phenylmethylsulfonyl fluoride (PMSF), and addition of cation $Ag^+$ or $Cu^{2+}$, and slightly inhibited by $Al^{3+}$. No significant inhibition was found with pepstatin, and addition of cation, $K^+$, $Ca^{2+}$, $Na^+$, $Fe^{2+}$ or $Mg^{2+}$. On the contrary, protease was enhanced by addition of divalent cation $Mn^{2+}$ (5 mM). Zymography analysis of concentrated culture supernatant revealed two major bands at 67 and 145 kDa. These results suggest that Chryseobacterium sp. JK1 strain produced extracellular neutral serine proteases which could apply in food industry.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.99-107
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• 2009

Strain PUPC1 produces an antifungal protease as well as plant growth promoting enzymes such as 1-aminocyclopropane-1-carboxylate (ACC) deaminase and phosphatase. Morphological, cultural, and physiological characteristics as well as 16S rRNA gene-sequence-based phylogenetic analysis confirmed the taxonomic affiliation of PUPC1 as Chryseobacterium aquaticum. The optimum growth of PUPC1 was observed at pH 6.0 and $30^{\circ}C$, and maximum protease production was observed in medium B amended with 1% tryptone, 0.5% sucrose, and 0.005% $MnCl_2$. The protease was purified by ammonium sulfate precipitation, Sephadex G-75 gel filtration chromatography, and electroelution from preparative SDS-PAGE. The protease had a molecular mass of 18.5 kDa. The optimum pH and temperature stability of the protease were pH 5.0-10.0 and temperature $40-70^{\circ}C$. Chryseobacterium aquaticum PUPC1 and its protease showed a broad-spectrum antifungal activity against phytopathogenic fungi. Strain PUPC1 also exhibited plant growth promoting traits. The objective of the present investigation was to isolate a strain for agricultural application for plant growth promotion and biocontrol of fungal diseases.

• Clinical and Experimental Pediatrics
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• v.50 no.7
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• pp.698-701
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• 2007

We report on two premature infants who developed nosocomial infection caused by Chryseobacterium meningosepticum in a neonatal intensive care unit (NICU). One premature infant developed sepsis, meningitis, and hydrocephalus, and was treated successfully with ciprofloxacin plus trimethoprim-sulfamethoxazole combination therapy for 4 weeks and with a ventriculoperitoneal shunt. The other premature infant, who was in a chronically debilitated state, had infection that had colonized only in the respiratory tract but had no clinical signs for 66 days. Extensive environmental surveillance demonstrated that the suction bottle apparatus was the source of infection. We prevented the spread of infection by closing the NICU temporarily, isolating the patients early in their infection, and eradicating the source of infection source.

• Journal of Applied Biological Chemistry
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• v.58 no.3
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• pp.247-251
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• 2015

In this study, a keratin-degrading bacterium was isolated from soil contaminated with feather waste. The isolated strain was identified as Chryseobacterium sp. P1-3 on the basis of the 16S rRNA gene sequence alignment. Chryseobacterium sp. P1-3 is currently used in various biotechnological applications (e.g., in the hydrolysis of poultry feathers). It hydrolyzed the feather meal within 2 days and possesses a high level of keratinase activity (98 U/mL). The keratinase, partially purified from this strain, prefers casein as a substrate and shows optimal activity at a temperature of $30^{\circ}C$ and at a pH of 8.0.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.351-353
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• 2017

Chryseobacterium sp. strain T16E-39, isolated from roots of a tomato plant, promotes plant growth and suppresses phytophthora blight and bacterial wilt diseases. The complete genome of strain T16E-39 consists of a circular chromosome with 4,872,888 base pairs with a G + C content of 35.22%. The genome includes 4,289 coding sequences, 15 rRNAs, and 71 tRNAs. We detected genes involved in phosphate solubilization, phytohormone regulation, antioxidant activity, chitin degradation, and the type IX secretion system (T9SS) that may be related to growth promotion and disease suppression in plants.

• Microbiology and Biotechnology Letters
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• v.32 no.4
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• pp.371-374
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• 2004

A bacterium producing the $\beta$-mannosidase was isolated from intestine of fresh fish. The isolate YB-29 has been identified as Chryseomeningosepticum on the basis on its 16S rRNA sequence, morphology and biochemical proper The $\beta$-mannosdiase activity was detected in both the culture filtrate and the cell extract of C. meningosepticum YB-29. The $\beta$-mannosidase of culture filtrate showed the maximum activity for hydrolysis of para-nitrophenyl-$\beta$-D-mannopyranoside at pH 5.0-6.0 and 55-$60^{\circ}C$. The enzyme was able to hydrolyze the oligomeric substrates such as mannobiose and mannotriose with higher activity for mannotriose than mannobiose.

• Biomedical Science Letters
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• v.25 no.3
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• pp.275-281
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• 2019

This study was performed to characterize the chromosomal metallo-${\beta}$-lactamases (MBLs) of Chryseobacterium indologenes isolated from Korea and to propose a clustering method of IND MBLs based on their amino acid similarities. Chromosomal MBL genes were amplified by PCR from 31 clinical isolates of E. indologenes. Nucleotide sequencing was performed by the dideoxy chain termination method using these PCR products. Antimicrobial susceptibilities were determined by the agar dilution method. PCR experiments showed that all 31 E. indologenes isolates contained all $bla_{IND}$ genes. DNA sequence analysis revealed that E. indologenes isolates possessed ten types of $bla_{IND}$ gene, including seven novel variants ($bla_{IND-8}$ to $bla_{IND-14}$). The most common combination of MBL was IND-2 (n = 18). Minimum inhibitory concentrations of imipenem and meropenem for the isolates harboring novel IND MBLs were ${\geq}16{\mu}g/mL$. IND MBLs were grouped in three clusters, based on amino acid similarities.

• Journal of Dairy Science and Biotechnology
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• v.40 no.2
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• pp.86-91
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• 2022

Chryseobacterium mulctrae KACC 21234^T is a novel species isolated from raw bovine milk. Psychrotrophic bacteria are considered contaminants and are hypothesized to originate from the environment. In this investigation, the C. mulctrae KACC 21234^T genome was determined to be 4,868,651 bp long and assembled into four contigs with a G+C ratio of 33.8%. In silico genomic analyses revealed the presence of genes encoding proteases (endopeptidase Clp, oligopeptidase b, carboxypeptidase) and lipases (phospholipase A(2), phospholipase C, acylglycerol lipase) that can catalyze the degradation of the proteins and lipids in milk, causing its quality to deteriorate. Additionally, antimicrobial resistance and putative bacteriocin genes were detected, potentially intensifying the pathogenicity of the strain. The genomic evidence presented highlights the need for improved screening protocols to minimize the potential contamination of milk by proteolytic and lipolytic psychrotrophic bacteria.