• KSBB Journal
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• 제4권1호
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• pp.11-14
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• 1989

Tower fermentor를 이용한 연속 알콜발효에서 cell re-cycle과 aeration에 대한 영향을 검토하였다. 균주는 floc-culationg 효모인 Saccharomyces cerecisiae TS4를 를 사용하였다. 15% glucose를 사용한 cell recycle system의 연속 알콜발효에서 cell 농도는 50%/1였고, ethanol productiv는 26.4g EtOH/l-hr로서 cell농도가 가장 높은 값을 나타내었으며, aeration rate는 3.8$\times$ $10^-^3$ VVM이상부터는 ethanol pro-ductivity가 감소하였다.

• 한국미생물·생명공학회지
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• 제20권1호
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• pp.85-90
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• 1992

Saccharomyces속 효모를 사용하여 미강을 배지로 하여 에탄올을 발효특성을 조사하였다. 액화효소와 당화효소를 전처리한 미강에서 여러 Saccharomyces속 효모들을 배양한 결과 Saccharomyces cerevisiae IFO 2346이 높은 에탄올 생성 및 유리아미노산 함량을 나타내었다. 균체성장은 발효 24시간에 $3\times 10^8$cell/ml로 증가하였으며, 발효 72시간후 4.7의 에탄올을 생성하였다. 유리아미노산 총량은 발효과정중 1,099mg/l에서 829mg/l로 감소하였으나, glutamic acid, histidine 및 isoleucine은 오히려 각각 218%, 31%5 및 1%48로 증가하였다.

• 한국식품과학회지
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• 제38권2호
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• pp.256-261
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• 2006

20여종의 Monascus속의 균주로 부터 mevinolin의 생산능이 우수하면서도 곰팡이 독소성분 citrinin을 생산하지 않는 우량균주를 선발하였으며, 콩시료에 대한 고상발효를 최적화하기 위한 영양배지의 조성물이 검토되었다. 선발된 M. pilosus IFO 480으로 발효시킨 홍국콩 발효물에 함유된 mevinolin의 주요 화합물은, 약리학적 활성형(drug)의 mevinolinic acid 밝혀졌다(91.8%). 따라서 홍국 발효콩은 생체활성형의 항 콜레스테롤 성분을 최대 0.22% 까지 함유하는, 안전한 건강 기능성식품 소재로서의 활용가능성이 높은 것으로 평가할 수 있다.

• 한국식품과학회지
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• 제43권2호
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• pp.235-239
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• 2011

홍국 배아미 5%와 10% 벌꿀용액으로 제조한 홍국 발효액종을 10-40% 첨가하여 밀가루 반죽의 레올로지 특성으로 falling number, RVA(rapid visco analyzer), farinograph, alveograph 등을 분석하였다. 홍국 발효액종 첨가량이 증가할수록 falling number 값이 낮아졌으며 10% 첨가시 $363{\pm}7.8s$, 20% 첨가시 $318{\pm}2.1s$이었다. 호화도 특성에서 홍국 발효액종 첨가량이 증가할수록 초기점도 온도와 breakdown은 상승하였고, 최고점도와 set-back값은 낮아졌다. Farinograph에서 대조구와 시험구간에 흡수율은 64.3-65.0%로 유의적 차이가 없었으나 반죽형성시간은 발효액종의 첨가량이 증가할수록 빨라졌고, 안정도는 저하되어 20% 첨가시는 9.3 min, 40% 첨가시는 3.0 min이었으며 약화도도 빨라졌다. Alveograph에서 $P_{max}(mm)$는 대조구가 158.0 mm이었으나 발효액종 첨가량이 많을수록 증가하여 40% 첨가시 190.0 mm이었다. 그러나 L, G, W 등의 값은 낮아졌다. 이상의 실험으로 홍국 발효액종을 20% 첨가까지는 반죽의 레올로지 특성인 제빵적성에 영향이 적어 빵 제조가 가능한 것으로 나타났다.

• Korean Chemical Engineering Research
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• 제50권5호
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• pp.759-765
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• 2012

바이오 디젤 생산량 증가에 따라 공정 중에 부산물로 발생하는 글리세린의 과잉공급 및 가격 하락이 이루어지고 있다. 이에 따라 글리세린에 기반한 다양한 화학제품생산과 관련된 연구가 활발히 진행되고 있으며 글리세린을 탄소원으로 한 1,3-프로판디올의 생물학적 생산은 그 중 하나이다. 1,3-프로판디올은 지금까지 화학적인 방법을 통해 생산되어 왔으나 생물학적인 방법을 통해 생산될 경우 공정의 친환경성 및 경제성 확보와 더불어 1,3-프로판디올을 중합원료로 하는 PTT (Poly(trimethylene terephthalate))의 바이오폴리머로서의 활용을 가능하게 한다. 그럼에도 글리세린 유래 1,3-프로판디올의 생물학적 생산의 경제성에 있어 핵심은 경제적인 분리공정의 수립에 있다. 본 총설에서는 1,3-프로판디올을 분리하기 위한 공정들에 대한 연구 동향을 소개하고 최근 에너지 절감과 더불어 1,3-프로판디올 분리와 부산물 제거를 동시에 달성할 있는 공정으로 주목받고 있는 수상이성분계 추출에 대한 연구개발 동향 및 전망을 제시하고자 한다.

• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1494-1500
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• 2012

Fermentation with filamentous fungi in a bioreactor is a complex dynamic process that is affected by flow conditions and the evolution of the rheological properties of the medium. These properties are mainly affected by the biomass concentration and the morphology of the fungus. In this work, the rheological properties of a fermentation with the fungus Beauveria bassiana under different hydrodynamic conditions were studied and the rheological behavior of this broth was simulated through a mixture of carboxymethyl cellulose sodium and cellulose fibers (CMCNa-SF). The bioreactor was a 10 L CSTR tank operated at different stir velocities. Rheological results were similar at 100 and 300 rpm for both systems. However, there was a significant increase in the viscosity accompanied by a change in the consistence index, calculated according to the power law model, for both systems at 800 rpm. The systems exhibited shear-thinning behavior at all stir velocities, which was determined with the power law model. The mixing time was observed to increase as the cellulose content in the system increased and, consequently, the efficiency of mixing diminished. These results are thought to be due to the rheological and morphological similarities of the two fungal systems. These results will help in the optimization of scale-up production of these fungi.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.422-427
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• 2003

Rhodopseudomonas palustris P4 can produce $H_2$ either from CO by water-gas shift reaction or from various sugars by anaerobic fermentation. Fermentative $H_2$ production by P4 is fast, but its yield is relatively low due to the formation of various organic acids. In order to increase $H_2$ production yield from glucose, P4 was investigated for the photo-fermentation of acetate which is a major by-product of fermentative $H_2$ production. Experiments were performed in batch modes using both light-grown and dark-grown cells. When the dark-grown P4 was challenged with light and acetate, $H_2$ was produced with the consumption of acetate after a lag period of 25 h. $H_2$ production was inhibited when a nitrogen source, especially ammonium, is present. When the dark-fermentation broth containing acetate was adopted for photo-fermentation with light-grown cells, $H_2$ production and concomitant acetate consumption occurred without a lag period. The $H_2$ yield was estimated as 2.4 - 2.8 mol $H_2/mol$ acetate and the specific $H_2$ production rate was as 9.8 ml $H_2/g$ cell${\cdot}$h, The fact that a single strain can perform both dark- and light-fermentation gives a great advantage in process development Compared to a one-step dark-fermentation, the combined dark- and light-fermentation can increase the $H_2$ production yield on glucose by two-fold.

• 한국축산식품학회지
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• 제20권1호
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• pp.21-29
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• 2000

This study was carried out to investigate the fermentation characteristics and storage of set-type yoghurt added mugwort extracts(AME) such as pH, growth of lactic acid bacteria, number of viable cells, viscosity, and sensory characteristics during 24 hours fermentation and 15 days storage. Addition of mugwort extracts was grown rapidly of lactic acid bacteria rather than that of control and also 4 or 8% AME groups were grown similar to control. The drop of AME pH of broth was less compared with control during incubation of lactic acid bacteria. The growth of lactic acid bacteria during incubation of AME yoghurt was not different of viable cell count between AME group and control in beginning time, but the viable cell count of AME groups were increased depended opon addition quantity of AME in ending time. Addition of mugwort extracts was not affect on pH change during yoghurt fermentation and increased a lactic acid bacteria number as well as no effect of yoghurt fermentation in ending time. The viscosity of yoghurt was almost not changed 3 hours after yoghurt mix and increased rapidly 6 hours after yoghurt mix. Although control and 0.5% AME group showed maximum viscosity at 18 hours of fermentation, 1 and 2% AME group showed linear increase until 24 hours of fermentation. Mugwort did not affect pH and viable cel number of lactic acid bacteria during 15 days storage 24 hours after fermentation. Sensory evaluation of the AME yoghurt showed that flavour, texture and acid taste were not affected by addition of mugwort. However, the appearance and taste were dropped by addition of mugwort.

• Journal of Microbiology and Biotechnology
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• 제21권6호
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• pp.652-658
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• 2011

The growth kinetics of Streptomyces noursei NRRL 5126 was investigated under different aeration and agitation combinations in a 5.0 l stirred tank fermenter. Poly-${\varepsilon}$-lysine biosynthesis, cell mass formation, and glycerol utilization rates were affected markedly by both aeration and agitation. An agitation speed of 300 rpm and aeration rate at 2.0 vvm supported better yields of 1,622.81 mg/l with highest specific productivity of 15 mg/l.h. Fermentation kinetics performed under different aeration and agitation conditions showed poly- ${\varepsilon}$-lysine fermentation to be a growth-associated production. A constant DO at 40% in the growth phase and 20% in the production phase increased the poly-${\varepsilon}$-lysine yield as well as cell mass to their maximum values of 1,992.35 mg/l and 20.73 g/l, respectively. The oxygen transfer rate (OTR), oxygen utilization rate (OUR), and specific oxygen uptake rates ($qO_2$) in the fermentation broth increased in the growth phase and remained unchanged in the stationary phase.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.121-124
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• 2000

본 연구의 목적은 식품부산물로부터 유기산 생산 및 분리 농축에 있다. 회분식 발효를 실시하여 균주의 최적 발효조건을 구하여 세포 재순환식 연속 발효공정에 적용한 결과, CSL의 최적 함량은 2.5%로 나타났으며 수율과 생산성은 각각 0.80g total acid/g glucose, 0.26g total acid/L/h로 향상 되었다. 세포 재순환식 연속발효 결과, 최대 유기산 생산성은 희석률 0.2/h에서 3.32g organic acid/L/h로 회분식 발효와 비교해 볼 때 최대 생산성으로는 13배, 세포량으로는 22배 증가한 것으로 나타났다. 또한, 최적 추출시스템은 30%w/w TOA/MIBK로 나타났으며, 발효액내의 유기산을 약 90%까지 분리 및 농축할 수 있음을 확인하였다.