• Journal of Microbiology and Biotechnology
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• 제32권1호
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• pp.117-125
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• 2022

Until recently, four types of cellobiose-fermenting Saccharomyces cerevisiae strains have been developed by introduction of a cellobiose metabolic pathway based on either intracellular β-glucosidase (GH1-1) or cellobiose phosphorylase (CBP), along with either an energy-consuming active cellodextrin transporter (CDT-1) or a non-energy-consuming passive cellodextrin facilitator (CDT-2). In this study, the ethanol production performance of two cellobiose-fermenting S. cerevisiae strains expressing mutant CDT-2 (N306I) with GH1-1 or CBP were compared with two cellobiose-fermenting S. cerevisiae strains expressing mutant CDT-1 (F213L) with GH1-1 or CBP in the simultaneous saccharification and fermentation (SSF) of cellulose under various conditions. It was found that, regardless of the SSF conditions, the phosphorolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-2 with CBP showed the best ethanol production among the four strains. In addition, during SSF contaminated by lactic acid bacteria, the phosphorolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-2 with CBP showed the highest ethanol production and the lowest lactate formation compared with those of other strains, such as the hydrolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-1 with GH1-1, and the glucose-fermenting S. cerevisiae with extracellular β-glucosidase. These results suggest that the cellobiose-fermenting yeast strain exhibiting low energy consumption can enhance the efficiency of the SSF of cellulosic biomass.

• 유기물자원화
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• 제3권1호
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• pp.35-42
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• 1995

고속발효기에 의해 처리된 음식물찌꺼기 퇴비의 부숙정도를 알아 보기 위해, 고속발효기 두 대를 이용하여 추천 운영조건으로 96시간동안 음식물 찌꺼기의 퇴비제조 실험을 실시한 후, 2차적으로 고속발효기를 통해 처리된 처리품을 약 1루베 규모의 정체식 퇴비화 장치를 이용하여 퇴비화 적정조건으로 재차 퇴비화를 실시하면서 각 단계별로 처리품의 이화학적 특성 및 식물독성을 측정하여 퇴비의 부숙정도를 분석하였다. 고속발효기를 이용한 음식물찌꺼기의 퇴비화시 약 60%정도의 감량효과를 가져와 취급성이 좋은 처리품을 얻을 수 있었다. 이에 반해 음식물찌꺼기 혼합물의 초기분해만을 도모 할 뿐 2~3일만에 완숙퇴비 제조는 불가능하였고, 식물에 시용시 발아억제와 뿌리생장 장해를 유발시켰다. 고속발효기에서 얻어진 처리품을 재차 정체식 퇴비시설을 이용하여 부숙시 최소한 6주 이상 부숙을 시켜야만 완숙된 퇴비로서 이용할 수 있을 것으로 판단되었다.

• Journal of Microbiology and Biotechnology
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• 제4권3호
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• pp.215-221
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• 1994

Two strains of yeast (RA-74-2 and RA-912) showing superior fermenting ability at a high temperature were isolated from soils and wastewaters by an enrichment culture method. Based on the morphological and physiological charateristics, the two strains were identified as Saccharomyces cerevisiae and Kluyveromyces marxianus, respectively. RA-74-2 was able to grow upto $43^{\circ}C$ and sustain similar fermenting ability in the temperatures range from 30 to $40^{\circ}C$. In addition, the sugar- and ethanol-tolerance of RA-74-2 were 30% (w/v) glucose and 10% (v/v) ethanol, which appeared to be higher than those of nine other industrial yeast strains currently being used in the alcohol factories. The thermotolerant ethanol fermenting yeast RA-912 showed identical growth in the temperatures range from 35 to $45^{\circ}C$ and was resistant to various heavy metals. The quality and quantity of byproducts of the isolated yeast strains in fermentation broth after fermentation at $40^{\circ}C$ and $45^{\circ}C$ were similiar with those obtained at $30^{\circ}C$. These results show that RA-74-2 can be adopted for the ethanol fermentation process where the expenses for cooling system is significant, and suggest that RA-912 may be applied in either SSF(simultaneous saccharification and fermentation) or Flash-fermentation process and RA-912 may be used as a gene donor for the development of thermotolerant ethanol-fermenting yeasts.

• 한국자원식물학회지
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• 제28권6호
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• pp.734-742
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• 2015

The purpose of this research was to find the most appropriate process for making yacon leaf tea. We applied both green tea and black tea brewing and fermenting methods for producing yacon leaf tea. This research included consumer test and descriptive analysis of professional trained panel on yacon tea tastes and flavors. Both consumer test and descriptive evaluation preferred yacon tea produced by black tea brewing and fermenting methods because it tasted less bitter and had a sweet, delicate taste. According to orthogonal transformation resulting from varimax rotation, first principal component was positively affected by black tea brewing and fermenting methods, while it was negatively affected by green tea brewing and fermenting methods. As a result, the study concluded black tea brewing and fermenting methods were appropriate for producing yacon leaf tea.

• 펄프종이기술
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• 제44권2호
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• pp.35-41
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• 2012

In this study, wheat starch adhesive was investigated the shape and structure of starch, the difference in characteristics such as chemical composition according to the fermenting period of 2 years or less. The fermenting period of wheat starch adhesive is 1 month, 2months, 4 months,6 months, 1 year, 2years old. The wheat starch adhesives were investigated total sugar contents, protein contents, properties of gelatinization, pH, the bonding strength and also observed the surface of starch,. As a result, the longer the fermenting period, the increasing in total sugar contents and decreasing in protein contents. The particle shape and surface were similar regardless of the period. In addition, properties of gelatinization according to the fermenting period also could not see the difference. In pH of the adhesive, the longer the fermenting period, the near to neutral. The adhesive was high bonding strength in 4 months, but appeared a tendency to decrease from 6 months. The damage assessment through the UV degradation in regard to the papers applied the adhesive was accomplished. Color difference was no change except 1 month. The 4 months and 6 months' pH was each 5.0, 5.2. But it was near to neutral that the 12 months and 24 months' pH was each 5.7, 5.9.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.598-606
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• 2001

A mathematical model is proposed that can depict the kinetics of simultaneous saccharification and fermentation (SSF) using steam-exploded wood(SEW) with a glucose- and cellobiose-fermenting yeast strain. Brettanomyces custersii. An expression to describe the reduction of the relative digestibility during the hydrolysis of the SEW is introduced in the hydrolysis model. The fermentation model also takes two new factors into account, that is, the effects of the inhibitory compounds present in the SEW hydrolysates on the microorganism and the fermenting ability of Brettanomyces custersii, which can use both glucose and cellobiose as carbon sources. The model equations were used to simulate the hydrolysis of the SEW, the fermentation of the SEW hydrolysates, and a batch SSF, and the results were compared with the experimental data. The model was found to be capable of representing ethanol production over a range of substrate concentrations. Accordingly, the limiting factors in ethanol production by SSF under the high concentration of the SEW were identified as the effect of inhibitory compounds present in the SEW, the enzyme deactivation, and a limitation in the digestibility based on the physical condition of the substrate.

• Journal of Microbiology and Biotechnology
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• 제27권9호
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• pp.1649-1656
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• 2017

In simultaneous saccharification and fermentation (SSF) for production of cellulosic biofuels, engineered Saccharomyces cerevisiae capable of fermenting cellobiose has provided several benefits, such as lower enzyme costs and faster fermentation rate compared with wild-type S. cerevisiae fermenting glucose. In this study, the effects of an alternative intracellular cellobiose utilization pathway-a phosphorolytic pathway based on a mutant cellodextrin transporter (CDT-1 (F213L)) and cellobiose phosphorylase (SdCBP)-was investigated by comparing with a hydrolytic pathway based on the same transporter and an intracellular ${\beta}$-glucosidase (GH1-1) for their SSF performances under various conditions. Whereas the phosphorolytic and hydrolytic cellobiose-fermenting S. cerevisiae strains performed similarly under the anoxic SSF conditions, the hydrolytic S. cerevisiae performed slightly better than the phosphorolytic S. cerevisiae under the microaerobic SSF conditions. Nonetheless, the phosphorolytic S. cerevisiae expressing the mutant CDT-1 showed better ethanol production than the glucose-fermenting S. cerevisiae with an extracellular ${\beta}$-glucosidase, regardless of SSF conditions. These results clearly prove that introduction of the intracellular cellobiose metabolic pathway into yeast can be effective on cellulosic ethanol production in SSF. They also demonstrate that enhancement of cellobiose transport activity in engineered yeast is the most important factor affecting the efficiency of SSF of cellulose.

• 현장농수산연구지
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• 제10권1호
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• pp.169-181
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• 2008

The purpose of this study was to produce Pleurotus ostreatus using fermenter with bag cultivation. These results are as follows. 1. While mushroom composts were being fermented in a fermenter, the physical property of the fermented composts was getting better when there isn't any screw or revolving flies in the fermenter and the strength of pressing the composts was getting less. 2. The composts were fermented well as slaked lime of 1% density added to the composts. 3. According to the result of examining our fermenting ways, composts were in the best condition after being fermented for 48 hours since the temperature in a fermenter has come to 60℃, which could be reached by heating the fermenter by 40℃ after putting compost materials and water into it. 4. The good condition of fermenting could be maintained by controlling the speed of revolving flies, therefore the speed be down when the temperature is above 60℃ and up bellow 60℃. 5. Since the composts had been added with 1.5~2% of cottonseed meal or rice bran, the fermented composts were in good condition and also the quantity and quality of the mushroom produced on the fermented composts were satisfied. 6. There were needed 7 hours of labour for 3days from the first day of putting composts into a fermenter for fermenting 3.5M/T(10,000~12,000bags of 750~800g per bag) of composts to the third day of finishing the fermenting work, and also the cost was 112,066￦(130$) including 52,066￦(60$) of electric charge and fuel expense.

• 대한본초학회지
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• 제24권4호
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• pp.101-106
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• 2009

Objectives : We investigated the anti-aging effects on skin with 9 Repetitive steaming and fermenting herbal composition extract (FHE). Methods : Herbal composition is comprised of Panax Ginseng, Rehmannia glutinosa, Polygonum multiflorum and Polygonatum Sibiricum. They steamed and fermented with Saccharomyces cerevisiae and Lactobacillus brevis by turns at 9 times. We measured various effects related to skin aging such as scavenging activity against free radical, cell proliferation, collagen synthesis and toxicity of 9 repetitive steaming and fermenting herbal composition extract were evaluated and compared with herbal composition extract (HE). Results : As the number of steaming and fermenting cycle increased free-radical scavenging activity were increased. But cell proliferating ratio was not increased when the number of steaming and fermenting cycle. The FHE could significantly increase the collagen synthetic ratio compared with HE treated group. And, FHE was showed no toxicity at all tested concentrations. Conclusions : The results of our study propose that FHE has good anti-aging effects on skin.

• 한국미생물·생명공학회지
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• 제47권4호
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• pp.565-573
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• 2019

섬유소계 바이오매스로부터 바이오 연료 등과 같은 유용한 물질을 생산하기 위해서는 바이오매스로부터 유래하는 혼합당을 효과적으로 대사할 수 있는 균주의 개발이 필수적이다. 본 연구에서는 xylose를 대사가 가능한 효모인 P. stipitis를 적응진화하여 cellobiose 대사효율이 향상되고 cellobiose와 xylose를 동시에 대사할 수 있는 균주를 개발하고자 하였다. 총 10회의 계대배양을 통해 얻어진 진화된 P. stipitis 돌연변이 균주는 모균주에 비해 6배 이상 증가된 cellobiose 대사속도를 나타내었으며 ethanol 생산수율을 0에서 0.4 (g ethanol/g cellobiose)로 향상시켰다. 아울러 본 실험에서 개발한 돌연변이 균주는 cellobiose와 xylose 혼합당 조건에서 모균주에 비해 2배 가까이 향상된 ethanol 생산 및 생산속도를 나타내었다.