• Preventive Nutrition and Food Science
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• 제18권4호
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• pp.269-272
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• 2013

This study was performed to compare the performance of Sanita-Kun dry medium culture plate with those of traditional culture medium and Petrifilm dry medium culture plate for the enumeration of the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet. Mesophilic aerobic bacteria were comparatively evaluated in milk, ice cream, ham, and codfish fillet using Sanita-Kun aerobic count (SAC), Petrifilm aerobic count (PAC), and traditional plate count agar (PCA) media. According to the results, all methods showed high correlations of 0.989~1.000 and no significant differences were observed for enumerating the mesophilic aerobic bacteria in the tested food products. SAC method was easier to perform and count colonies efficiently as compared to the PCA and PAC methods. Therefore, we concluded that the SAC method offers an acceptable alternative to the PCA and PAC methods for counting the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products.

• Journal of Microbiology
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• 제40권1호
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• pp.82-85
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• 2002

The aerobic batch growth of Issatchenkia orientalis DY252 with glucose and fructose medium was investigated at 32$\^{C}$ and pH 5.0. Aerobic ethanol production was evident with yeast I, orientalis. A diauxic lag of about 1 h between growth on glucose and growth on ethanol during batch culture was observed. However, no diauxic growth occurred with fructose. As the incubation temperature was increased from 32 to 39$\^{C}$, viability at the end of each batch culture declined significantly, from 93 to 43%, Unlike the effect of temperature, viability was not greatly affected by incubation pH, and cell yield values in a range of 0.45-0.48 were obtained. In order to overcome overflow metabolism, a fedbatch culture under glucose limitation was carried out. Compared with aerobic batch culture, about 10% improvement in cell yield was achieved with a fed-batch culture in optimal conditions.

• 한국물환경학회지
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• 제31권6호
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• pp.599-609
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• 2015

OSA (oxic-settling-anaerobic)공정은 종래 활성슬러지법(conventional activated sludge)의 잉여슬러지 감량을 목적으로 슬러지 반송라인에 혐기조가 추가된 공정이다. 본 연구에서는 호기조(1)-혐기조-호기조(2)가 순차적으로 구성된 OSA 모의공정의 슬러지 감량원리를 조사하기 위해 각 반응조의 세포 내 에너지 전달물질(ATP, NAD(H), NADP(H)) 변화를 관찰하였다. 시간이 경과함에 따라 호기조 및 혐기조 모두 에너지전달물질이 급격히 감소하였다. 혐기조의 경우 호기조(1)과 (2)보다 낮은 에너지를 함유하는 것으로 나타났으며, 혐기조를 거친 호기조(2)의 경우 호기조(1) 보다 에너지 전달물질이 낮은 수준으로 관찰되었다. 또한, OSA 공정에서 내생호흡을 유도하여 슬러지를 감량하는 혐기조의 화학적 산소요구량 (SCOD), 체류시간 및 온도변화에 따른 호기조(1)과 (2)의 에너지량 차이를 확인한 결과 낮은 농도의 SCOD, 긴 체류시간 및 높은 온도는 호기조(2)의 세포 내 에너지량을 감소시켰다. 혐기조 및 호기조(2)의 세포 내 에너지 수준은 각각 호기조(1)의 57.73% 및 39.12% 수준으로, 두 단계의 호기조 사이에 추가된 혐기조는 OSA 공정의 세포 내 에너지 수준을 낮출 뿐 아니라, CAS 공정보다 적은 양의 슬러지가 생산하였다. 본 연구결과를 토대로, 호기조 사이에 추가된 혐기조의 운전조건에 따라 각 반응조의 세포 내 에너지 수준의 조절뿐만 아니라 잉여슬러지의 생성을 제어할 수 있을 것이라 생각된다.

• 한국지반환경공학회 논문집
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• 제11권11호
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• pp.27-36
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• 2010

본 연구는 정읍시에서 배출되는 하수슬러지, 축산 분뇨, 음식물 쓰레기를 대상으로 Pilot-scale($100m^3$) 초고온 호기성 퇴비화 공정에서의 온도, pH, C/N비, 함수율, 유기물 함량, 그리고 부피 등 물리 화학적 영양 인자를 평가하였다. 각각의 대상 물질은 1차 발효(유기성 폐기물+종균)와 2차 발효(유기성 폐기물+종균+반송 퇴비)로 나누어 수행하였다. 퇴비화가 진행됨에 따라 교반과 송풍만으로 열공급 없이 온도는 1,2차 발효에서 최고온도 $90{\sim}105^{\circ}C$가 되었다. pH, $O_2$, $CO_2$, $NH_3$, 농도 변화는 전형적인 미생물에 의한 유기물 분해 양상을 보여주었으며, 다른 모든 물리 화학적 인자들은 일반 호기성 퇴비화의 성능 이상을 보여주었다. 발효가 완료된 후 퇴비의 중금속 농도는 퇴비 비료 규격 기준 농도에 적합한 것으로 나타났다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.147-152
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• 2004

Aerobic cometabolism of cis-1,2-dichloroethylene (c-DCE) and c-DCE epoxide by a butane-grown mixed culture was evaluated. Transformation of c-DCE resulted in the concomitant generation of c-DCE epoxide. Chloride release studies showed nearly complete oxidative dechlorination of c-DCE (approximately 75%). Mass spectrometry confirmed tile presence of a compound with mass-to-charge-fragment ratios of 112, 83, 48, and 35. The values are in agreement with the spectra of a chemically synthesized c-DCE epoxide. Some evidences indicating the involvement of the monooxygenase in the transformation of c-DCE epoxide are: 1) $O_2$ requirement for c-DCE transformation and butane degradation; 2) butane inhibition on c-DCE transformation and vice versa; 3) the inactivation of c-DCE and c-DCE epoxide transformations by acetylene (a known monooxygenase inactivator); and 4) tire inhibition of c-DCE epoxide transformation by c-DCE.

• 한국환경과학회지
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• 제14권10호
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• pp.955-963
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• 2005

From sludge of S municipal wastewater treatment plant in Busan, Korea, we isolated the denitrifier DN-9 which showed the ability of denitrification under aerobic conditionby the color change and gas formation in liquid culture with Giltay medium. The isolated strain was identified as Pseudomonas sp. DN-9 on the basis of the morphological, physiological, biochemical and nucleotide sequence analysis of l6S rRNA. The isolated strain, Pseudomonas sp. DN-9, has cytochrome $cd_1$, nirS of nitrite reductase. By the co-existance of additional ammonium and nitrate ion, the strain was not affected largely on growth in SL series broth. It seemed the result of denitrification. Although Pseudomonas sp. DN-9 has a good nitrate reduction activity under aerobic condition, the activity is less than Pseudomonas stutzeri in same cultivation condition. However, Escherichia coli had little the activity of aerobic denitrification and Pseudomonas putida showed lower activity of aerobic denitrification than Pseudomonas sp. DN-9 and Pseudomonas stutzeri in this study.

• Journal of Microbiology and Biotechnology
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• 제20권3호
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• pp.485-493
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• 2010

A modified graphite felt electrode with neutral red (NR-electrode) was shown to catalyze the chemical oxidation of nitrite to nitrate under aerobic conditions. The electrochemically oxidized NR-electrode (EO-NR-electrode) and reduced NR-electrode (ER-NR-electrode) catalyzed the oxidation of $1,094{\pm}39$ mg/l and $382{\pm}45$ mg/l of nitrite, respectively, for 24 h. The electrically uncharged NR-electrode (EU-NR-electrode) catalyzed the oxidation of $345{\pm}47$ mg/l of nitrite for 24 h. The aerobic bacterial community immobilized in the EO-NR-electrode did not oxidize ammonium to nitrite; however, the aerobic bacterial community immobilized in the ER-NR-electrode bioelectrochemically oxidized $1,412{\pm}39$ mg/l of ammonium for 48 h. Meanwhile, the aerobic bacterial community immobilized on the EU-NR-electrode biochemically oxidized $449{\pm}22$ mg/l of ammonium for 48 h. In the continuous culture system, the aerobic bacterial community immobilized on the ER-NR-electrode bioelectrochemically oxidized a minimal $1,337{\pm}38$ mg/l to a maximal $1,480{\pm}38$ mg/l of ammonium to nitrate, and the community immobilized on the EU-NR-electrode biochemically oxidized a minimal $327{\pm}23$ mg/l to a maximal $412{\pm}26$ mg/l of ammonium to nitrate every two days. The bacterial communities cultivated in the ER-NR-electrode and EU-NR-electrode in the continuous culture system were analyzed by TGGE on the $20^{th}$ and $50^{th}$ days of incubation. Some ammonium-oxidizing bacteria were enriched on the ER-NR-electrode, but not on the EU-NR-electrode.

• 한국미생물·생명공학회지
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• 제24권4호
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• pp.485-492
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• 1996

myo-Inositol, a growth factor for Saccharomyces cerevisiae (S. cerevisiae), has been known to be incorporated into phosphatidylinositol (PI), which is a kind of phospholipid in the cell membrane, by a membrane-associated PI-synthesizing enzyme. The deficiency of myo-inositol in S. cerevisiae adversely affected the membrane structure and function. On the basis of biochemical functions of myo-inositol, the effect of deficiency of myo-inositol on the aerobic glucose metabolism was investigated by measuring specific oxygen uptake rate (Q$_{O2}$) used as an indicator representing the respiratory capacity of S. cerevisiae in batch and continuous cultures. The respiratory capacity of aerobic glucose metabolism in S. cerevisiae was also monitored after glucose pulse-addition in a continuous culture (D=0.2, 1/hr), in which glucose was utilized through respiratory metabolism. The deficiency of myo-inositol was found to lead to both the decrease of the maximum specific oxygen uptake rate (Q$_{O2max}$) observed from the batch as well as in the continuous culture experiment and the decrease of the respiratory capacity of aerobic glucose metabolism of S. cerevisiae determined from the glucose pulse-addition experiment, in which the glucose flux into respiratory and fermen- tative metabolism was quantitatively analyzed.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.885-892
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• 2011

The bacterial communities in the intestinal tracts of earthworm were investigated by culture-dependent and -independent approaches. In total, 72 and 55 pure cultures were isolated from the intestinal tracts of earthworms under aerobic and anaerobic conditions, respectively. Aerobic bacteria were classified as Aeromonas (40%), Bacillus (37%), Photobacterium (10%), Pseudomonas (7%), and Shewanella (6%). Anaerobic bacteria were classified as Aeromonas (52%), Bacillus (27%), Shewanella (12%), Paenibacillus (5%), Clostridium (2%), and Cellulosimicrobium (2%). The dominant microorganisms were Aeromonas and Bacillus species under both aerobic and anaerobic conditions. In all, 39 DNA fragments were identified by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. Aeromonas sp. was the dominant microorganism in feeds, intestinal tracts, and casts of earthworms. The DGGE band intensity of Aeromonas from feeds, intestinal tracts, and casts of earthworms was 12.8%, 14.7%, and 15.1%, respectively. The other strains identified were Bacillus, Clostridium, Enterobacter, Photobacterium, Pseudomonas, Shewanella, Streptomyces, uncultured Chloroflexi bacterium, and uncultured bacterium. These results suggest that PCR-DGGE analysis was more efficient than the culturedependent approach for the investigation of bacterial diversity and the identification of unculturable microorganisms.

• 한국식생활문화학회지
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• 제23권3호
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• pp.397-402
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• 2008

This study was conducted to evaluate the quality characteristics of domestic as well as imported fermented skate. Three types of fermented skate products were analyzed for proximate composition, pH, VBN, ammonia-N, free amino acids, and fatty acids. The results indicated that the domestic fermented skate contained large amounts of TMAO. Also, the domestic and imported fermented skates each contained approximately 7.1 log CFU/g and $5.8{\sim}6.5$ log CFU/g of aerobic bacteria, respectively, and 585.9 mg and $384.1{\sim}398.5$ mg of total free amino acids, respectively; all samples contained high levels of taurine, anserine, lysine, alanine, glycine, proline, and ${\beta}-alanine$. For fatty acid composition, the domestic fermented skate contained 11 different types of saturated fatty acid and 16 types of unsaturated fatty acid, whereas the imported skate contained 8 types of saturated fatty acid and $10{\sim}15$ types of unsaturated fatty acid. Overall, the results suggest that domestic fermented skate is a better source of amino acids and essential fatty acids and contains more aerobic bacteria than imported fermented skate.