• 한국미생물·생명공학회지
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• 제22권5호
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• pp.531-537
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• 1994

This study was undertaken with objective of optimizing the conditions of fermentation in an aqueous two-phase system which is composed of polyethylene glycol (PEG) 20000 and crude dextran (Dx). The data were obtained and analyzed using the Box-Wilson's experimental design protocol and the response surface methodology. To reach this end a multilinear polynomial regres- sion model was developed, which can be utilized for the purpose of optimizing the extractive fermentation. Optimum conditions for batch fermentation with aqueous two phase system were found to be at 4.2~5.4% PEG/3.2~4.2% Dx range. The composition of the center was 4.8% PEG/ 3.6% Dx. Optimum operating conditions for initial sugar concentration and fermentation time were approximately 160 g/l, and 21~22 hr, respectively. Fermentation in the aqueous two phase system composed of 5% PEG/4% Dx showed increase of 23% in ethanol concentration, of 9.5% in ethanol yield, and of 19% in ethanol productivity as compared to the case of fermentation of neat Jerusalem artichoke juice.

• KSBB Journal
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• 제6권2호
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• pp.175-180
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• 1991

The quantitative effects of molecular weight and concentrations of two phase-forming polymers-polyethylene glycol and crude dextran on the two phase extractive ethanol fermentation were investigated using a Box-Wilson central composite protocol. The regression model obtained was used in order to determine optimum compositions of aqueous two phase system. In the aqueous two phase extractive ethanol fermentation of Kluyueromyces fragilis CBS 1555 with Jerusalem artichoke juice, it was found from the regression model that the variables influenlcing on ethanol fermentation were PEG concentration, time, Dx concentration, and PEG molecular weight strongly in order. The interaction of PEG concentration and PEG molecular weight was also found, and the effect of PEG concentration decreased with increase in molecular weight of PEG. The ethanol concentration incresed with increase in molecular weight of PEG, and with decrease in concentration of PEG. In conolusion, maximum concentration of ethanol produced was obtained at the following compositions; PEG MW 20000, Dx concentration ranged from 4% to 5%, and PEG concentration ranged from 3% to 7%.

• 한국미생물·생명공학회지
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• 제16권5호
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• pp.358-362
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• 1988

세포외 효소를 효율적으로 생산하기 위한 새로운 발효시스템으로서 수성 2상계를 시험하였다. 실험대상으로는 Bacillus amyloliquefaciens 균주에 의하여 $\alpha$-amylase를 생산하는 시스템을 선정하였다. Polyethylene glycol 5%, dextran 7%, 그리고 발효액이 88% 포함된 수성 2상계 발효시스템에 의하여 $\alpha$-amylase의 생합성은 25% 정도 증가하였으며 효소의 비활성화는 관찰되지 않았다. 또한 Polyethylene glycol 이 효소의 생합성을 증진시키는 것으로 관찰되었다. 효소의 생합성을 증가시키며 동시에 효소를 발효액으로부터 분리하기 위하여는 polyethylene glycol을 성장도중에, dextran은 효소의 활성이 최고에 달한 후에 발효액에 가하는 발효방법이 바람직하다.

• KSBB Journal
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• 제9권5호
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• pp.443-449
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• 1994

여러 가지 조성의 PEG 20000jDx로 구성한 수성 이상계를 사용한 에탄올 추출발효실험을 통하여 K. fragilis에 의한 돼지감자 주스의 발효 특성을 초기 당농도 및 생성 알코올 농도의 함수로 규명하여 다음의 결과를 얻었다. 균체의 비증식속도 빛 에탄올 비생성속도는 PEG 및 Dx 농도가 낮을수록 증가하였다. 비증식속도는 조성에 무관하게 초기 당농도 $80g/\ell$에서 최대치를 보였고, 에탄올 비생성속도는 $120g/\ell$최대치를 보였다. 생성 알코올 농도에 의한 저해 영향은 비증식속도에 대하여 지수함수형 을, 에탄올 비생성속도에 대하여 쌍곡선함수형을 나타냈다. Dx 농도가 2.5~5% 범위에셔 PEG 농도 가 낮을수록 에탄올 저해 영향은 감소하였다. 총괄 에탄올 생산성은 초기 당농도가 증가할수록 높았으 며 생산성이 최대치에 도랄하는 소요시간도 당농도가 증가함에 따라 증가하였다. 시간별 에탄올 생산 속도는 초기 당농도 $160g/\ell$ 에서 가장 높은 값을 보 였다. 총괄 에탄올 생산성은 대조실험에 비하여 수 성이상계 추출발효를 통하여 1.2배 이상 증가하였고 초기 당농도가 높을수록 이상계 추출발효가 더욱 유리한 것으로 나타났다.

• KSBB Journal
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• 제8권2호
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• pp.178-184
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• 1993

Extractive fermentations with the extract of Jerusalem artichoke in an aqueous-two-phase-system of polyethyleneglycol(PEG) and dextran(Dx) were investigated to obtain the effects of composition of PEG and Dx on both fermentation ,characteristics and partition ratio of alcohol. The specific growth rate of K. Fraglis CBS 1555 increased with a decrease of concentration of PEG and Dx. It augmented along with concentration of initial sugar up to 80g/l but decreased thereafter. The specific production rate of alcohol showed a rising tendency up to 100g/lof initial sugar, whereafter represented a decreasing trend. The partition ratio of alcohol between two phases augmented according to decrease of Dx comic. and increase of PEG cone. regardless of initial sugar concentrations. The ratio, however, decreased with Increment of initial sugar concentration at constant composition of PEG and Dx. The partition coefficient of alcohol had an ascending effect to the increase of PEG cone, but it had little effect on the changes of concentrations of Dx and initial sugar. The present study suggests that the optimum composition of PEG and Dx in the aqueous-two-phase-system by extractive fermentation were around 6.5%(w/v) of PEG and 3%(w/v) of Dx in considerations of emulsion state, sedimentation and separation of two phases, alcohol partition ratio, and specific growth rate.

• 한국균학회지
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• 제42권4호
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• pp.328-332
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• 2014

Two-phase fermentation을 통한 Beauveria bassiana 149균주의 대량 배양을 위한 탄소원, 질소원, 기질 그리고 배양 조건 선발 실험을 실시하였다. 1차 액체 배양을 위한 적정 탄소원으로는 옥수수 분말, 전분 그리고 쌀가루가, 질소원으로는 펩톤과 효모 분발을 첨가한 것에서 포자 생산량이 높았다. 포자 대량 생산을 위한 기질 및 첨가물로는 톱밥+밀기울+옥수수 분말, 톱밥+밀기울, 쌀겨+밀기울 혼합에서 포자 생산량이 높았다. B. bassiana 149 균주의 포자 대량 생산을 위한 고체 배양 결과, 포자 생산량은 $30^{\circ}C$ 배양에서 $20^{\circ}C$보다 2배 정도 높은 경향을 보였다. B. bassiana 149 균주의 포자 생산량은 $25^{\circ}C$, 수분함량 60%와 70%에서 배양 시 $26.9{\times}10^8conidia/g$와 $38.6{\times}10^8conidia/g$로 40%와 50%의 $13.9{\times}10^8conidia/g$와 $11.6{\times}10^8conidia/g$ 보다 상당히 높았다.

• Journal of Animal Science and Technology
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• 제56권3호
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• pp.10.1-10.7
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• 2014

An experiment was conducted to investigate the effects of dietary supplementation with citrus pulp, fish by-product, and Bacillus subtilis fermentation biomass on the growth performance, apparent total tract digestibility (ATTD) of nutrients, and fecal microflora of weanling pigs. A total of 180 weaned piglets (Landrace ${\times}$ Yorkshire ${\times}$ Duroc) were randomly allotted to three treatments on the basis of body weight (BW). There were six replicate pens in each treatment with 10 piglets per pen. Dietary treatments were corn-soybean meal-based basal diet supplemented with 0 (control), 2.5, and 5.0% citrus pulp, fish by-product, and B. subtilis fermentation biomass. The isocaloric and isoproteineous experimental diets were fed in mash form in two phases (d 0 ~ 14, phase I and d 15 ~ 28, phase II). Dietary treatments had significant linear effects on gain to feed ratio (G:F) in all periods, whereas significant linear effects on ATTD of dry matter (DM), gross energy (GE), and ash were only observed in phase I. Piglets fed diet supplemented with 5.0% citrus pulp, fish by-product, and B. subtilis fermentation biomass showed greater (p < 0.05) G:F (phase I, phase II, and overall) as well as ATTD of DM, GE, and ash (phase I) than pigs fed control diet. Dietary treatments also had significant linear effects on total anaerobic bacteria populations by d 14 and 28. In addition, piglets fed diet supplemented with 5.0% citrus pulp, fish by-product and B. subtilis fermentation biomass showed greater (p < 0.05) fecal total anaerobic bacteria populations (d 14 and 28) than pigs fed control diet. Dietary treatments had no significant effects (linear or quadratic) on average daily gain (ADG), average dial feed intake (ADFI; phase I, phase II, and overall), or fecal populations of Bifidobacterium spp., Clostridium spp., and coliforms (d 14 and 28). These results indicate that dietary supplementation with 5.0% citrus pulp, fish by-product, and B. subtilis fermentation biomass has the potential to improve the feed efficiency, nutrient digestibility, and fecal microflora of weanling pigs.

• 한국미생물·생명공학회지
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• 제44권2호
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• pp.145-149
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• 2016

해조류 중 홍조류인 K. alvarezii로부터 동시 당화 발효(SSF)를 위한 효소 당화 및 균 배양 온도를 검토하고, 기존의 동시 당화 발효(SSF) 를 개선하기 위해 2단계 동시 당화 발효(SSF)를 수행하였다. 효소 당화와 균 성장 온도를 고려하였을 때 동시 당화 발효(SSF)에 적용하는 배양 온도는 40°C를 선택하여 실험을 진행하였다. 비순치 효모(wild type)와 고농도 갈락토오스에 순치한 효모(adapted yeast to galactose)를 이용한 동시 당화 발효(SSF)를 실시한 결과 발효 156시간에 9.1 g/l의 에탄올 수율(Y_EtOH) 0.24와 10.2 g/l의 에탄올 수율(Y_EtOH) 0.27을 나타내었다. 이러한 기존의 동시 당화 발효(SSF)를 개선한 2단계 동시 당화 발효(SSF)는 에탄올 생산 수율이 0.27에서 0.35로 27.5% 증가하였으며, 에탄올 발효 시간도 156시간에서 96시간으로 61.5% 감소하였다. 이러한 연구결과는 해양 바이오매스인 해조류로부터 바이오연료 생산과정에 있어 기초적인 정보를 제공할 것이다.

• 한국축산시설환경학회지
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• 제6권2호
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• pp.73-81
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• 2000

A two-phase anaerobic digestion system for the treatment of swine waste was constructed in a commercial hog farm. The digester system was composed of 4 major units; slurry storage pit, acidogenic digester, methanogenic digester and sedimentation pit. A biogas boiler unit was also attached to maintain the digester temperature of 37$^{\circ}C$. Substrate lading was made with 2hr-interval by pumping about 2.1$m^3$ of slurry type swine waste from the slurry pit into the acidogenic digester, which corresponds to hydraulic retention time of 4 days for the acidogenic digester and of 11 days for the methanogenic digester. Digester temperature were well maintained as the set temperature of 37$^{\circ}C$ in the methanogenic digester, while the temperature in the acidogenic digester showed around 34$^{\circ}C$. pH also showed a steady-state results of 7.3 in the acidogenic digester and of 7.6 in the methanogenic digester during the operation period. Average biogas production rate was 0.66$m^3$/$m^3$ digester volume. Reduction rate of total solid and volatile solid were 42.8% and 5.8%, respectively. Total nitrogen and ammonia nitrogen were not reduced during the anaerobic fermentation, however, most of VFAs seemed to be converted to the biogas,. These fermentation performance data may suggest that he newly developed a two-phase anaerobic digester for the swine waste treatment worked so successfully.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.932-937
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• 2004

In situ extraction by organic solvent was studied in order to improve the recovery yield of hydrocarbon from the culture of Botryococcus braunii, a green colonial microalga. When the solvent mixture of octanol as an extractive solvent and n-octane as a biocompatible solvent was added to a two-phase column, the algal growth was seriously inhibited, even at a low concentration of polar octanol. Therefore, a two-stage cell-recycle extraction process was proposed to improve the contact area between the organic phase and the aqueous phase. The hydrocarbon recovery with in situ cell-recycle extraction showed a three-fold increase (57% of cell) in yield over that with two-phase extraction. In addition, over 60% of the hydrocarbon could be recovered without serious cell damage by downstream separation when this process was applied to the culture broth after batch fermentation.