• Korean Journal of Microbiology
• /
• v.26 no.2
• /
• pp.129-136
• /
• 1988

To investigate the influence of cosubstrate supplement and ammonium sulfate on lignin degradation by Pseudomonas diminuta KM-4-2, isolated in the laboratory, the strain was cultured on the lignin media which contained lignin as a source of carbon and the culture filtrate was analyzed by Sephadex G-75 column chromatography. It was found that polymerization was not appeared unlike wood-rot fungi. When the carbohydrates were added, the peak of lignin at 280nm by UV scanning spectra of the filtrate, was significantly increased. In order to determine the effect of ammonium sulfate on the ligninolytic activity, the isolated strain was incubated in the media containing 0.1%, 0.25% and 0.5% of nitrogen concentration in the Warburg flask and the rate of oxygen uptake was esitmated by Warbuge Respirometer. As a result, the activity was maximum at 0.1% of nitrogen concentration and thereafter decreased in parallel with nitrogen concentration.

• Journal of Microbiology
• /
• v.37 no.4
• /
• pp.200-205
• /
• 1999

7-Aminocephalosporanic acid (7-ACA) is the initial compound in preparation of cephalosporin antibiotics widely used in clinical treatment. Bacteria producing glutaryl 7-ACA acylase, which convert cephalosporin C to 7-ACA, has been screened in soil samples. A bacterial strain exhibiting high glutaryl 7-ACA acylase activity, designated KAC-1, was isolated and identified as a strain of Pseudomonas diminuta by characterizing its morphological and physiological properties. The screening procedures include culturing on enrichment media containing glutaric acid, glutamate, and glutaryl 7-aminocephalosporanic acid as selective carbon sources. To enhance enzyme production, optimal cultivation conditions were investigated. This strain grew optimally at pH 7 to 9 and in temperatures of 20 to 40 C, but acylase production was higher when the strain was grown at 25 C. Glutaric acid, glutamate and glucos also acted as inducers for acylase production. In a jar fermenter culture, P. diminuta KAC-1 produce acylase in a growth-associated manner. The substrate specificity of KAC-1 acylase by cell extract showed that this enzyme had specificity toward glutaryl 7-ACA, glutaryl 7-ADCA, but not cephalosporin C.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.2
• /
• pp.326-328
• /
• 2001

Pseudomonas diminuta (ATCC 19146) has been typically used in the bacterial challenge test for validation of the sterilizing filtration process. Cell size is critical for determining the retention characteristics of membrane filters with pore-size of $0.2{\mu}m$. The changes of cell sizes after osmotic shocks at 150, 260, 500, and 700 mosM were measured by a particle size analyzer and the changes of their buoyant densities were analyzed with a Percoll gradient. The results indicated that there were no significant differences when cells were cultured in 260 mosM medium and osmotically shocked at 500 and 700 mosM. However, the osmotically shocked cells at 150 mosM showed a 38% increase of the cell size compared to the cells at 260 mosM. From these study, we concluded that the worst case condition for validation of a sterilizing filter would be 500 mosM, not because of changes in the cell size, but due to decrease in cell viability under those conditions.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.3
• /
• pp.452-457
• /
• 2001

The glutaryl 7-aminocephalosporanic acid (glutaryl 7-ACA) acylase was purified from Pseudomonas diminuta KAC-1 cells isolated from soil, and characterized. The acylase was purified by procedures including ammonium sulfate fractionation and column chromatographies on DEAE-Sepharose, Phenyl-Sepharose, Q-Sepharose, and Superose 12H/R. The negative acylase was found to be composed of two subunits with molecular masses of approximately 55 kDa and 17 kDa, respectively. The isoelectric point of the enzyme was 4.0. The specific activities of the purified acylase were 8.0 and 7.0 U/mg on glutaryl 7-ACA and glutaryl 7-aminodesacetoxy cephalosporanic acid (glutaryl 7-ADCA), respectively, and $K_m$ values were 0.45 mM for glutaryl 7-ADCA and 0.67 mM for glutaryl 7-ADCA. The enzyme had a pH optimum at 8.0 and a tmperature optimum at $40^{\circ}C$. The acylase catalyzed the synthesis of glutaryl 7-ACA from glutaric acid and 7-ACA as well as the hydrolysis of glutaryl 7-ADCA, although the reaction rate of the synthesis was slower than that of the hydrolysis. In addition, it was found that the enzyme had a glutaryl transferase activity, thereby transferring the glutaryl group from one cephalosporin nucleus to another.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.24 no.4
• /
• pp.631-635
• /
• 1995

In order to develop effective manufacturing method and to improve quality of low-salt fermented squid(10% of table salt), we investigated the effects of temperature, salinity and pH on the growth of Staphylococcus xylosus, Micrococcus varians, Pseudomonas diminuta and Pseudomonas D2 isolated from of low-salt fermented squid and the growth characteristics of these bacteria during fermentation were elucidated. All bacteria showed good growth during the process of low-salt fermented squid(pH 6~7 ; concentration of NaCl, 7~10% ; temperature, 7~1$0^{\circ}C$) and their cell numbers increased as fermentation proceeded under the same fermentation condition.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.10 no.6
• /
• pp.510-515
• /
• 2005

Pseudomonas cepacia BY21 was found to produce glutaryl acylase that is capable of deacylating glutaryl-7-aminocephalosporanic acid (glutaryl-7-ACA) to 7-aminocephalosporanic acid (7-ACA), which is a starting material for semi-synthetic cephalosporin antibiotics. Amino acids of the reported glutaryl acylases from various Pseudomonas sp. strains show a high similarity (>93% identity). Thus, with the known nucleotide sequences of Pseudomonas glutaryl acylases in GenBank, PCR primers were designed to clone a glutaryl acylase gene from P. cepacia BY21. The unknown -subunit gene of glutaryl acylase from chromosomal DNA of P. cepacia BY21 was cloned successfully by PCR. The -subunit amino acids of P. cepacia BY21 acylase (GenBank accession number AY948547) were similar to those of Pseudomonas diminuta KAC-1 acylase except that Asn408 of P. diuminuta KAC-1 acylase was changed to Leu408.

• Korean Journal of Food Science and Technology
• /
• v.31 no.6
• /
• pp.1619-1627
• /
• 1999

Microbiological characteristics of gamma irradiated low salt squid Jeot-gal were examined. Following the fermentation periods, total bacterial cell, Lactobacillus spp., Staphylococcus spp., Streptococcus spp., Pseudomonas spp. and yeast cell number were counted on their selective media and some acid forming bacteria and Pseudomonas spp. were identified. As the gamma irradiation dose increased, the microbial density of early fermentation phase was reduced and the growth rate was delayed. The repression effects on microbiological growth by gamma irradiation were to be higher as salt concentration increased. Adequate conditions of salt concentration and gamma irradiation for low-salt squid Jeot-gal preparation were 10% and 10 kGy, respectively. Lactobacillus sp. 2, Micrococcus varians and Streptococcus sp. I were isolated from 5% salt containing squid Jeot-gal, and Micrococcus morrhuae was from 20% only while Lactobacillus plantarum and Lactobacillus brevis were widespread. Lactobacillus brevis, Pediococcus halophilus and Pseudomonas diminuta were sensitive and Lactobacillus plantarum, Micrococcus morrhuae and Pseudomonas sp. 3 were resistant to gamma irradiation. The diversity of microflora decreased as salt concentration decreased and gamma irradiation dose increased.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.10
• /
• pp.4910-4916
• /
• 2012

Changes of low concentrated nitrogen-phosphate removal efficiency were investigated in 4 strains of marine bacteria applied to ceramic media. Marine bacteria were isolated and identified from Gwangyang bay. Growth rates and removal efficiencies of $NH_3$-N of 4 strains of marine bacteria applied to ceramic media were increased approximately 3 fold and over 30% than control group, respectively. A. hydrophila and P. diminuta had highest ${NO_3}^-$-N and phosphate removal efficiencies, respectively. This results showed that ceramic media is very nice material for improvement of nitrogen-phosphate removal efficiency and isolated marine bacteria may be useful to control nitrogen-phosphate at low concentration in field.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.7
• /
• pp.3267-3274
• /
• 2012

371 strains of marine bacteria were isolated from Gwangyang bay in Korea. The dominant species were identified as Pseudomonas aeruginosa, Aeromonas hydrophila, P. fluorescens, P. paucimobilis, Chryseomonas luteola and P. vescularis. To screen marine bacteria capable of removing nutrients and organics, marine bacteria was inoculated in 10 mL of marine broth 2216 (DIFCO) with $NH_3-N$ (100 mg/L), ${NO_3}^{-}-N$ (100 mg/L), and ${PO_4}^{-3}-P$ (10 mg/L) with 1.0% (v/v), and incubated for 12 h. Results from the screening test, showed that the removal efficiencies for $COD_{Cr}$, ammonia niterogen, nitrate nitrogen, and phosphate were over 25% for 16 strains, 15% for 9 strains, 50% for 63 strains, and 15% for 80 strains, respectively. Aeromonas hydrophila, Chryseomonas indologenes, Pseudomonas diminuta, Vibrio parahaemolyticus were selected for nutrients removal experiments. For the batch test, 4 species of marine bacteria were inoculated in modified marine broth containing with nutrients($COD_{Cr}$ 250 mg/L, $NH_3-N$ 40 mg/L, ${NO_3}^{-}-N$ 40 mg/L, ${PO_4}^{3-}-P$ 10 mg/L, respectively), incubated for 10 hr and the removal efficiencies were measured.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.2
• /
• pp.195-204
• /
• 2013

While structured packing modules are known to be efficient for surface wetting and gas-liquid exchange in abiotic surface catalysis, this model study explores structured packing as a growth surface for catalytic biofilms. Microbial biofilms have been proposed as selfimmobilized and self-regenerating catalysts for the production of chemicals. A concern is that the complex and dynamic nature of biofilms may cause fluctuations in their catalytic performance over time or may affect process reproducibility. An aerated continuous trickle-bed biofilm reactor system was designed with a 3 L structured packing, liquid recycling and pH control. Pseudomonas diminuta established a biofilm on the stainless steel structured packing with a specific surface area of 500 $m^2m^{-3}$ and catalyzed the oxidation of ethylene glycol to glycolic acid for over two months of continuous operation. A steady-state productivity of up to 1.6 $gl^{-1}h^{-1}$ was achieved at a dilution rate of 0.33 $h^{-1}$. Process reproducibility between three independent runs was excellent, despite process interruptions and activity variations in cultures grown from biofilm effluent cells. The results demonstrate the robustness of a catalytic biofilm on structured packing, despite its dynamic nature. Implementation is recommended for whole-cell processes that require efficient gas-liquid exchange, catalyst retention for continuous operation, or improved catalyst stability.