• Environmental Engineering Research
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• v.24 no.3
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• pp.376-381
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• 2019

In this study, a poly(vinyl) alcohol/sodium alginate (PVA/SA) mixture was used to fabricate core-shell structured gel beads for autotrophic single-stage nitrogen removal (ASNR) using aerobic and anaerobic ammonia-oxidizing bacteria (AAOB and AnAOB, respectively). For stable ASNR process, the mechanical strength and oxygen penetration depth of the shell layer entrapping the AAOB are critical properties. The shell layer was constructed by an interfacial gelling reaction yielding thickness in the range of 2.01-3.63 mm, and a high PVA concentration of 12.5% resulted in the best mechanical strength of the shell layer. It was found that oxygen penetrated the shell layer at different depths depending on the PVA concentration, oxygen concentration in the bulk phase, and free ammonia concentration. The oxygen penetration depth was around $1,000{\mu}m$ when 8.0 mg/L dissolved oxygen was supplied from the bulk phase. This study reveals that the shell layer effectively protects the AnAOB from oxygen inhibition under the aerobic conditions because of the respiratory activity of the AAOB.

• Environmental Engineering Research
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• v.19 no.1
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• pp.23-29
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• 2014

In this study, aerobic granules were applied to a lab-scale aerobic granule sludge airlift reactor (AGSAR) and the ammonium nitrogen oxidation performance was evaluated at different ammonium nitrogen loading rate (NLR). At least 99% of the initial ammonium nitrogen was oxidized at an NLR of 0.27 and 0.53 kg $NH_4{^+}-N/m^3{\cdot}day$, for both aerobic granules (control), and nitrifying aerobic granules (NAGs). The ammonium nitrogen oxidation deteriorated, when the NLR was increased to 1.07 kg $NH_4{^+}-N/m^3{\cdot}day$. The NAGs were characterized by complete nitrification, while partial nitrification was observed in the control.

• Journal of Food Hygiene and Safety
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• v.12 no.2
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• pp.111-116
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• 1997

For the purpose of improving hygienic quality of dried-Angelica Keiskei Koidz powder, the effect of ozone treatment and gamma irradiation on the microbial decontamination and physicochemical properties were investigated. Gamma irradiation at 5 to 7.5 kGy resulted in sterilizing total aerobic bacteria, molds and coliforms below detective levels, while ozone treatment for 8 hours up to 18 ppm did not sufficiently eliminate the total aerobic bacteria of the sample. The physicochemical properties of the sample were not changed by gamma irradiation up to 7.5 kGy, whereas, ozone treatment caused remarkable changes in pH, TBA value, chlorophyll, carotenoid and fatty acid compositions. Therefore, this investigation demonstrated conclusively that gamma irradiation was more effective than ozone treatment for decontaminating and sterilizing the dried-Angelica Keiskei Koidz powder, with minimal effect on the physicochemical properties analyzed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.465-467
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• 1997

The comparative effects of ozone treatment and gamma irradiation on the sterilization, physicochemical properties and sensory quality of red pepper powder were investigated. As for the sterilization of microorganisms, 7.5~10 KGy of gamma irradiation completely eliminated the coliforms, yeast and molds, and total aerobic bacteria. On the other hand, ozone treatment failed to eliminate the highly contaminated microbial load, especially total aerobic bacteria. The physicochemical properties including capsaicin, capsanthin, browning, fatty acid compositions and sensory quality were not significantly changed by gamma irradiation up to 10 kGy, whereas ozone treatment caused significant changes in fatty acid compositions and destruction of natural pigments (p<0.05). The above results led us to conclude that gamma irradiation was more effective than ozone treatment for the sterilization and maintenance of physicochemical and sensory qualities of red pepper powders.

• Journal of Radiation Industry
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• v.8 no.1
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• pp.1-5
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• 2014

This study investigated the reduction of microbial population and sensory properties in red pepper powders irradiated by gamma ray, electron beam, and X-ray. Populations of total aerobic bacteria and yeast & molds in red pepper powders were decreased by irradiation treatment in a dose-dependent manner. Gamma ray, electron beam, and X-ray at doses above 8 kGy caused 100% inhibition on growth of aerobic bacteria in red pepper powders. Inhibitory activity of X-ray on sterilization of red pepper powders was significantly equal to or higher compared to gamma ray and electron beam. Color and off flavor in red pepper powders were no significant difference among the control and samples irradiated with gamma ray, electron beam, and X-ray. As a result, the gamma ray, electron beam, and X-ray irradiation can be used to sterilize the microbial growth in red pepper powders without quality loss.

• Korean Journal of Microbiology
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• v.23 no.3
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• pp.223-229
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• 1985

We have previously isolated seven strains of spiral form bacteria, which have shown several similar characteristics to Leptospira from patient with epidemic pulmonary hemorrhagic fever and matural paddy water. Further studies have performed to characterize them. All of the isolated bacteria were aerobic, gram negative and spiral form and their growth were completely inhibited at temperature below $13^{\circ}C\;and\;50^{\circ}C$. In sensitivity test to drugs, the bacteria were resistant to the bile salts, 5-Fu and Amphotericine B, but sensitive to the 8-Azaguanine. The isolated bacteria as well as 5 serotypes of Leptospira interrogans reacted the patient sera and it was also shown that antisera from rabbit immunized with the isolated bacteria reacted with 5 serotypes of Leptospira interrogans. These results suggest that the isolated bacteria may belong to the genus Leptospira.

• Korean Journal of Veterinary Research
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• v.51 no.3
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• pp.243-247
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• 2011

It is important to identify the bacteria in snakes because they can cause disease; importantly, bacteria such as Stenotrophomonas maltophilia, Escherichia coli, Proteus vulgaris etc. could be pathogens especially in hospitalized, debilitated hosts, and immunocompromised patients. To analyze the distribution of snakes' bacteria in petting zoo, samples from 20 snakes were collected from 2002 to 2008. Nine bacteria species were isolated from both oral and cloaca while four and six species were identified only from oral and cloaca, respectively. Except for Actinobacter sp., all of the identified strains are opportunistic pathogens, and most of them can cause nosocomial infections in humans. Present results indicate that prevalence of various zoonotic bacterial strains in snakes could be involved in potential transfer of these bacteria into caretakers and other animals. Therefore, it needs to examine the antibiotic resistance of these pathogens to prevent outbreaks.

• Journal of Food Hygiene and Safety
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• v.2 no.1
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• pp.21-27
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• 1987

ABS1'RACT-Comparative effects of gamma irradiation and ethylene oxide treatment on the sterilization, and physicochemical and sensory quality of dried marine products(shrimp, anchovy) were investigated. Population of mesophilic total bacteria, aerobic spores and tolerant bacteria of samples were $10^{3}-10^{7}/g,\;10^{7}\;to \;10^{4}/g\;and\;10^{2}\;to\;10^{6}/g$, respectively. Coliforms and molds were found only in dried shrimp as $10^{2}/g$. Mesophilic total bacteria, aerobic spores and acid tolerant bacteria were reduced by over 2 to 4 log cycles with irradiation of 5 to 7 kGy and they were completely sterilized by irradiation dose of 7 to 10 kGy. $D_{10}$ value of mesophilic total bacteria of samples ranged from 1.53 to 2.73 kGy. Coliforms and molds were sterilized at 5 to 7 kGy irradiation but ethylene oxide treatment proved insufficient to eliminate the microorgainsms. An optimum dose of irradiation was less detrimental than ethylene oxide treatment to phpicochemical properties of the samples, such as the pH, TBA value, TMA-N, amino acids, minerals and color difference. Sensory quality after three months of storage showed that the overall acceptability of irradiated sample was higher than that of the non treated control as well as ethylene oxide treated samples.amples.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.1
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• pp.100-110
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• 2020

Objective: The objective of this study was to isolate proteolytic microorganisms and evaluate their effects on proteolysis in total mixed ration (TMR) silages of soybean curd residue. Methods: TMRs were formulated with soybean curd residue, alfalfa or Leymus chinensis hay, corn meal, soybean meal, a vitamin-mineral supplement, and salt in a ratio of 25.0: 40.0:30.0:4.0:0.5:0.5, respectively, on a basis of dry matter. The microbial proteinases during ensiling were characterized, the dominate strains associated with proteolysis were identified, and their enzymatic characterization were evaluated in alfalfa (A-TMR) and Leymus chinensis (L-TMR) TMR silages containing soybean curd residue. Results: Both A-TMR and L-TMR silages were well preserved, with low pH and high lactic acid concentrations. The aerobic bacteria and yeast counts in both TMR silages decreased to about 10⁵ cfu/g fresh matter (FM) and below the detection limit, respectively. The lactic acid bacteria count increased to 10⁹ cfu/g FM. The total microbial proteinases activities reached their maximums during the early ensiling stage and then reduced in both TMR silages with fermentation prolonged. Metalloproteinase was the main proteinase when the total proteinases activities reached their maximums, and when ensiling terminated, metallo and serine proteinases played equally important parts in proteolysis in both TMR silages. Strains in the genera Curtobacterium and Paenibacillus were identified as the most dominant proteolytic bacteria in A-TMR and L-TMR, respectively, and both their proteinases were mainly with metalloproteinase characteristics. In the latter ensiling phase, Enterococcus faecium strains became the major sources of proteolytic enzymes in both TMR silages. Their proteinases were mainly of metallo and serine proteinases classes in this experiment. Conclusion: Proteolytic aerobic bacteria were substituted by proteolytic lactic acid bacteria during ensiling, and the microbial serine and metallo proteinases in these strains played leading roles in proteolysis in TMR silages.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.991-996
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• 2003

Determination of regional microbial contamination in the process of rice rolled in dried laver (Kimbab) and effects of gamma irradiation on the improvement of hygienic quality and shelf stability were investigated. Total aerobic bacterial distribution of raw materials of Kimbab were; 10$^{6}$ ∼10$^{7}$ CFU/g in dried laver, 10$^3$ CFU/g in cucumber and below 10 CFU/g in steamed rice, ham, fried egg, and salted radish. Total coliform bacteria were 10$^3$ CFU/g in dried laver and detected below detection limit (10 CFU/g) in other raw materials. And it was arithmetically calculated that the levels of total aerobic bacteria and coliform bacteria in Kimbab does not exceed 10$^{5}$ CFU/g and 10$^1$ CFU/g under the aseptic process, respectively. However, microbial contamination levels in just prepared Kimbab in a market were about 10$^{6}$ CFU/g of total aerobic and coliform bacteria. Therefore, it was considered that microbial contamination of Kimbab is mainly originated from environmental uptake during the preparation. The representative media for putrefying bacterial growth were steamed rice. Coliform bacteria were mainly increased in ham and fried egg during storage. The bacteria in dried laver were radio-resistant and survived at 3 kGy of gamma irradiation. Coliform bacteria on EMB agar plate were eliminated at the dose of 2 kGy. The sensory acceptability of 2 kGy irradiated Kimbab was stable and the Kimbab can be preserved for 24 hour at 15$^{\circ}C$. Therefore, it was considered that optimal irradiation dose for radicidation of Kimbab was 2 kGy.