• Journal of Microbiology and Biotechnology
• /
• 제21권5호
• /
• pp.519-524
• /
• 2011

The correlation between alcoholic fermentation rate, measured as carbon dioxide ($CO_2$) evolution, and the rate of hydrogen sulfide ($H_2S$) formation during wine production was investigated. Both rates and the resulting concentration peaks in fermentor headspace $H_2S$ were directly impacted by yeast assimilable nitrogenous compounds in the grape juice. A series of model fermentations was conducted in temperature-controlled and stirred fermentors using a complex model juice with defined concentrations of ammonium ions and/or amino acids. The fermentation rate was measured indirectly by noting the weight loss of the fermentor; $H_2S$ was quantitatively trapped in realtime using a pre-calibrated $H_2S$ detection tube which was inserted into a fermentor gas relief port. Evolution rates for $CO_2$ and $H_2S$ as well as the relative ratios between them were calculated. These fermentations confirmed that total sulfide formation was strongly yeast strain-dependent, and high concentrations of yeast assimilable nitrogen did not necessarily protect against elevated $H_2S$ formation. High initial concentrations of ammonium ions via addition of diammonium phosphate (DAP) caused a higher evolution of $H_2S$ when compared with a non-supplemented but nondeficient juice. It was observed that the excess availability of a certain yeast assimilable amino acid, arginine, could result in a more sustained $CO_2$ production rate throughout the wine fermentation. The contribution of yeast assimilable amino acids from conventional commercial yeast foods to lowering of the $H_2S$ formation was marginal.

• Fisheries and Aquatic Sciences
• /
• 제25권10호
• /
• pp.525-536
• /
• 2022

Photosynthetic bacteria (PSB) attract considerable interest as useful microorganisms; nevertheless, a generalized culture technique has not been previously reported owing to difficulty in their cultivation. Therefore, a simple culture technique suitable for public use was investigated. Among the PSB tested, the strain Rhodobacter azotoformans EBN-7 was the most suitable for scale-up production because it showed the highest specific growth rate (0.20 h^-1) on basal medium. In scale-up cultivation (500 L), R. azotoformans EBN-7 showed 4.50 × 10¹⁰ colony-forming units mL^-1 (number of viable cells), dry cell weight of 26.8 g/L, and a specific growth rate of 0.15 h^-1. Cultivation using this final culture broth (as seed culture) in a 15 L simple reactor was successful, with maintenance of cell activity evident. For use as seed culture, the maximum allowable preservation period of R. azotoformans EBN-7 at 4℃ was 3 months. When R. azotoformans EBN-7 cultivated in a simple technique was applied to shrimp aquaculture water, NH₄⁺-N was reduced from 0.61 mg/L to 0.24 mg/L (by 60.7%) in 4 days in comparison with the control. Thus, this simple culture technique using R. azotoformans EBN-7 has the potential for a good removal efficiency of NH₄⁺-N, making seed culture easier and suitable for public use.

• 생명과학회지
• /
• 제21권11호
• /
• pp.1511-1517
• /
• 2011

페난스렌은 다환방향족 탄화수소의 일종으로서 미량으로도 인체에 강한 해를 미칠 수 있는 주요 환경오염 물질이다. 미생물을 이용한 페난스렌 제거 목적으로 중국 쑤저우(Suzhou) 지역의 유류 오염토양에서 페난스렌을 강력하게 분해하는 세균을 분리하였다. 16S rDNA 염기서열 결정에 의하여 이 세균은 Sphingobacterium sp. SW-09로 동정되었으며 PCR 증폭을 통하여 페난스렌 분해 유전자인 nahH를 가지고 있음이 확인되었다. 이전의 연구에서 포천일대의 군부대에서 분리된 강력한 페난스렌 분해세균인 Staphylococcus sp. KW-07과 이번에 분리된 Sphingobacterium sp. SW-09을 이용하여 이들의 페난스렌 분해능을 비교분석하였다. 그 결과, 쑤저우 지역에서 분리된 Sphingobacterium sp. SW-09이 최소배지와 실제토양에서 모두 Staphylococcus sp. KW-07보다 강하게 페난스렌을 분해하는 것으로 나타났다. 결과적으로 이번에 분리된 Sphingobacterium sp. SW-09을 사용하여 유류 오염토양의 환경정화에 사용할 수 있을 것으로 판단된다.

• 한국축산식품학회지
• /
• 제29권5호
• /
• pp.640-646
• /
• 2009

발효유제품, 김치, 및 신생아 분변 등에서 유산균을 분리하여 isoflavone 전환 능력을 평가하였다. 유산균 중 높은 수준의 $\beta$-glucosidase 활성을 보인 균주는 Enterococcus sp. 77, L. paracasei, Lactobacillus sp. 712, L. brevis ATCC 8287, Lactococcus sp. KU107, L. acidophilus KCNU, L. plantarum L155 등으로 나타났다. 이들 유산균에 대하여 유당 발효성을 평가하여 가장 우수한 유산균을 선발하여 API, 16S rDNA를 분석한 결과 Lactobacillus plantarum으로 동정되었으며 이 활성 유산균을 Lactobacillus plantarum YS712로 명명하였다. Lactobacillus plantarum YS712는 pH 2.5에서도 약 50% 이상의 강한 생존율을 보였으며 DPPH 라디칼 소거능도 95.8%로, 선발된 유산균 중 가장 높은 라디칼 소거능을 나타내었다. 이로써 Lactobacillus plantarum YS712는 발효식품 및 유제품에 다양하게 이용할 가치가 있다고 판단된다.

• 한국지반공학회지:지반
• /
• 제13권1호
• /
• pp.137-146
• /
• 1997

A Study on the 본 연구에서는 플라스틱드레인을 이용하여 진공수평배수에 의해 개량된 준설 점토 지반의 압밀거동을 파악하기 위하여 대형 압밀시험을 실시하였으며, 실험 결과가 포텐결중공원주의 압밀이론을 이용한 수치해석에 의해 비교 검토되었다. 본 연구 실험결과에 의하면 수평배수진공압밀시험은 점토층 내부의 함수비 및 간극수압과 드레인 배수 속도 등이 진공압밀 시간 경과에 따라 감소되어 압밀이 급속하게 진행되고 있음이 확인되었다. 점토층 중공원주의 방사류에 대한 선형포텐샬압밀이론을 이용하여 수치 압밀해석 결과 간극수압은 확산 형태보다 흙의 변형과 투수에 의해 크게 좌우되고 있으므로, 지표면 부근에서의 실측 침하량은 압밀응력증가율 a가 -0.5정도에서 수치해석과 일치하며 또한 드레인 설치 부근에서의 점토층 침하량은 Baryon 압밀이론과 유사한 거동을 나타내고 있다. 최종적으로 수평 배수에 대한 적당한 선택과정을 포함한 설계 및 시공관리가 시험결과에 의하여 설명 되었으며 포텐셜압밀이론은 진공배수시 수평드레인에 의한 압밀거동을 정확하게 예측할 수 있다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제28권7호
• /
• pp.1006-1013
• /
• 2015

Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high ${\gamma}$-aminobutyric acid (GABA)-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164) at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i) 0 mg/kg, ii) 25 mg/kg, iii) 50 mg/kg, and iv) 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at $28.83{\pm}3.85^{\circ}C$ and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (p<0.05) by the increasing supplementation of the dietary GABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (p<0.05) than that of the hens fed the basal diet, whereas cholesterol level was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009) and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to improve laying performance and egg quality in heat-stressed hens.

• 한국가축번식학회지
• /
• 제21권2호
• /
• pp.85-93
• /
• 1997

These experiments were carried out to examine the development capacity of sexed and then bisected embryo from 8-cell to morula stage. Antisera to histocompatibility-Y(H-Y) antigen were prepared in inbred SD female rat by repeated immunization of spleen cell or testis supernatant from males of same strain. Male and female embryos were separated by delaying development of embryos against H-Y antibody. After sexing, rabbit embryos were bisected and aggregated. The results obtained from the these experiments were summuerized as follows: 1. When mouse and rabbit 8-, 16-cell and morular embryos were culature in H-Y antiserum, the ratio of embryo which has developed to hatching blastocyst was 53.4, 46.3 and 57.4% in mouse embryos, and 49.0, 52.0 and 61.0% in rabbit embryo, respectively. The ratio of mouse and rabbit embryos developed to hatching blastocyst showed nearly natural sex rate(50%), except rabbit mourla showed a little higher ratio(61.0%) as compared to natural sex ratio. 2. When rabbit demi-embryos from 8-, 16-cell embryo and morula were cultured, the percentage of demi-embryos was 70, 68 and 58% without zona pellucida removed, and 62, 69 and 51% with zona pellucida. The rate of aggregation was higher in 8- and 16-cell demi-embryos than in morula demi-embryo. 4. When sexed-demi-embryo was aggregated with another demi-embryo with demi-embryo with same sex, the rate of embryo developed to blastocyst was 60, 50 and 25%, respectively. Eight-cell demi-embryo showed highest rate. In conclusion, it showed that H-Y antiserum which was made by rat spleen cell enabled sexing rabbit embryos. And when rabbit sexed 8-, 16-cell and morula demi-embryo were aggregated, they were developed to eu-blastocyst which suggested the potential of sexed embryo manipulation.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제55권1호
• /
• pp.35-41
• /
• 2006

Although reachers have studied for a long time, they don't make criteria for anesthesia depth. anesthetists can't make a prediction about patient's reaction. Therefor, patients have potential risk such as poisonous side effect late-awake, early-awake and strain reaction. EEG are received from twenty-five patients who agreed to investigate themselves during operation with Enflurane-anesthesis in progress of anesthesia. EEG are divided pre-anesthesia, before incision of skin, operation 1, operation 2, awaking, post-anesthesia by anesthesia progress step. EEG is applied pre-processing, base line correct, linear detrend to get more reliable data. EEG data are handled by electronic processing and the EEG data are calculated by bicoherence. During pre-anesthesia and post anesthesia, appearance rate of bicoherence value is observed strong appearance rate in high frequency range($15\~30Hz$). During the anesthesia of patient, a strong appearance rate is revealed the low frequency area(0~10Hz). After bicoherence is calculated by percentage of a appearance rate, that is, Bicpara$\#$1, Bicpara$\#$2, Bicpara$\#$3 and Bicpara$\#$4 parameter are extracted. In result of bicoherence analysis, Bicpara$\#$2 and Bicpara#4 are considered that the best parameter showed progress of anesthesia effectively. And each separated bicoherence are calculated by average bicoherence's numerical value, divide by 2 area, appear by each BicHz$\#$1, BicHz$\#$2, and observed BicHz$\#$1/BicHz$\#$2's change. In result of bicoherence analysis, BicHz$\#$1, BicHz$\#$2 and BicHz$\#$1/BicHz$\#$2 are considered that the best parameter showed progress of anesthesia effectively. In conclusion, I confirmed the anesthesia progress phase, concluded to usefulness of parameter on bispectrum and bicoherence analysis and evaluated the depth of anesthesia. In the future, it is going to use for doctor's diagnosis and apply to protect an medical accident owing to anesthesia.

• 미생물학회지
• /
• 제49권1호
• /
• pp.83-89
• /
• 2013

채소 재배 비닐하우스 토양으로부터 chlorpyrifos (CP) 분해능을 지니고 있는 CY6 균주를 분리하였다. 형태학적 특징 및 16S rRNA 염기서열의 계통발생학적 유사성을 기초로 CY6 균주는 Naxibacter sp.로 확인되었다. CP는 Naxibacter sp. CY6 의해 탄소 및 인의 단일원으로 이용되었다. 우리는 액체배양에서 Naxibacter sp. CY6의 다른 OP 살충제 분해 양상을 살펴 보았다. Naxibacter sp. CY6는 parathion 및 methyl parathion, diazinon, cadusafos, ethoprop를 분해할 수 있었으며, 이 때 이들은 탄소 및 인의 단일원으로 제공되었다. 또한, CP (100 mg/kg)가 함유된 토양에 Naxibacter sp. CY6 ($10^8$ CFU/g)를 접종한 것이 접종하지 않은 토양에서 보다 약 90%의 높은 분해 정도를 나타냈었다. Naxibacter sp. CY6는 살충제가 오염된 토양의 정화에 사용할 수 있는 잠재성을 지니고 있다.

• 한국미생물·생명공학회지
• /
• 제34권2호
• /
• pp.136-142
• /
• 2006

Haematococcus pluvialis는 astaxanthin을 많이 생산하는 미세조류로써 astaxanthin은 항산화제로 면역반응을 강화시켜주며 항암효과 등을 가지고 있다. 그런데 야생종의 낮은 생장속도와 astaxanthin의 생산에는 한계가 있기 때문에 이를 극복하기위해 돌연변이 방법을 사용하였다. 돌연변이 방법으로는 자외선 조사와 EMS와 colchicines 처리를 사용하여 야생종보다 colony가 크고 더 붉은 것은 선택하였다. 선별된 돌연변이들은 carotenoid 생합성과정을 억제하는 nicotine 과 diphenylamine을 이용하여 다시 선별하였다. 그때 생존율은 40-50%이었고 여기서 선별된 균주들을 다시 규모를 키워 배양한 결과 자외선 처리한 돌연변이인 U15-5가 야생종보다 세포당 total carotenold 생산량이 1.68배 증가하였고, colchicine 처리한 DS와 M4-3은 생장속도가 $20\sim30%$ 증가하였다.