• Carbon letters
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• 제17권1호
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• pp.1-10
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• 2016

Lignocellulosic biomass conversion to biofuels such as ethanol and other value-added bio-products including activated carbons has attracted much attention. The development of an efficient, cost-effective, and eco-friendly pretreatment process is a major challenge in lignocellulosic biomass to biofuel conversion. Although several modern pretreatment technologies have been introduced, few promising technologies have been reported. Microwave irradiation or microwave-assisted methods (physical and chemical) for pretreatment (disintegration) of biomass have been gaining popularity over the last few years owing to their high heating efficiency, lower energy requirements, and easy operation. Acid and alkali pretreatments assisted by microwave heating meanwhile have been widely used for different types of lignocellulosic biomass conversion. Additional advantages of microwave-based pretreatments include faster treatment time, selective processing, instantaneous control, and acceleration of the reaction rate. The present review provides insights into the current research and advantages of using microwave-assisted pretreatment technologies for the conversion of lignocellulosic biomass to fermentable sugars in the process of cellulosic ethanol production.

• Journal of Microbiology and Biotechnology
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• 제1권1호
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• pp.12-16
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• 1991

Previously RP1::Tn951 which is a derivative of RP1 containing the lactose transposon Tn951 was introduced into Z. mobilis strain ZM6l00, and RP1::Tn951 was integrated into its genome to yield ZM6306. The galactose operon was incorporated into ZM6306 to yield ZM6307 for more efficient utilization of lactose. Batch culture study has been carried out on Z. mobilis strains, ZM6306 ($lac^+$ ) and ZM6307 ($lac^+$ , $gal^+$ ), which can convert lactose directly to ethanol. Using a medium containing 80 gㆍ$1^{-1}$ glucose and 40 gㆍ$1^{-1}$ lactose, it was found that ZM6306 and ZM6307 produced maximum ethanol concentration of 40 gㆍ$1^{-1}$ and 42 gㆍ$1^{-1}$, respectively, whereas parent strain ZM6 produced 37 gㆍ$1^{-1}$.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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• pp.115-121
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• 1992

In order to broaden the spectrum of substrate utilization of a Gram negative bacterium Zymomonas mobilis which has a great potential as an industrial ethanol producing microorganism, cloning of $\alpha$-amylase gene into Z. mobilis ZM4 was tried. The $\alpha$-amylase gene was isolated from Bacillus stearothermophilus. By Southern blot analysis, it was proven that the $\alpha$-amylase gene fragment was originated from a naturally occuring plasmid of B. stearothermophilus ATCC 31195. To place $\alpha$-amylase gene under the control of Z. mobilis promoter, two different Z. mobilis expression vectors, pZA26 and pLOI204, were used. The truncated $\alpha$-amylase gene was then introduced into these vectors. Both qualitative and quantitative activities of $\alpha$-amylase were observed in Z. mobilis cells harboring these plasmids with the $\alpha$-amylase gene inserted. Gas chromatographic analysis of ethanol showed that one of the Z. mobilis transconjugants was capable of producing 67 mM ethanol from rich medium(RM) containing 5% soluble starch as a sole carbon source.

• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.297-302
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• 1999

Simultaneous saccharification and fermentation (SSF) experiments were carried out with a lignocellulosic biomass. The effects of temperature on enzymatic saccharification and the ethanol fermentation were also investigated. The batch SSF process gave a final ethanol concentration of 10.44 g/l and equivalent glucose yield of 0.55 g/g, which was increased by 67％ or higher over the saccharification at 42℃. The optimal operating condition was found to vary in several parameters, such as the transmembrane pressure, permeation rate, and separation coefficient, related to the SSF combined with membrane system (semi-batch system). When the fermentation was operated in a semi-batch mode, the efficiency of the enzymes and yeast lasted three times longer than in a batch mode.

• 한국식품영양과학회지
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• 제18권1호
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• pp.34-39
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• 1989

쌍화차의 제조공정중 추출은 용매를 50% etanol 로 하고 그 첨가량은 원료량의 10배로 하였을 때 가장 수율이 높았고, 추출온도 및 시간은 $90^{\circ}C$ water bath에서 8시간 추출하는 방법이 가장 효과적으로 생산비를 절감할 수 있었다. 또한 특수성분의 HPLC분석 결과는 50% ethanol로 추출한 제품이 물로 추출한 것보다 높은 양을 나타내었고 특히 Decursinol성분의 경우에 물추출로는 38.59 PPM, 50% ethanol추출로는 298.02PPM으로 가장 현저한 차이를 나타내었다.

• KSBB Journal
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• 제7권1호
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• pp.67-71
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• 1992

50개의 폴리프로필렌 실관과 3개의 테르폰 실관으로 구성된 실관반응기에서 Saccharomyces cerevisiae효모를 이용하여 알콜의 연속 생산을 연구하였다. 생산된$CO_2$는 테프론 실관으로 내어 보냈고 과잉효모 세포는 shell-side를 통하여 제거하였다. Shell-side 부피를 기준으로 세포농도는 266g/L였고 알콜 생산성은 205g/L를 얻었다. 질소 결핍배지를 사용했을 경우 생산성이 너무 낮아 실제 응용할 가치는 없었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권2호
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• pp.55-60
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• 1998

Various Saccharomyces cerevisiae strains were transformed with a 2 ${\mu}$-based multicopy expression plasmid, pYIGP, carrying Kluyveromyces marxianus inulinase gene under the control of GAPDH promoter. Among then two strains, SEY2102 and 2805, showed high levels of cell growth and inulinase expression, and were selected to study their fermentation properties on inulin. Jerusalem artichoke inulin was more effective for cell growth (10∼11 g-dry wt./L at 48 hr) and inulinase expression (1.0 units/mL with SEY2102/pYIGP and 2.5 units/mL with 2805/pYIGP) than other inulin sources such as dahlia and chicory. It was also found that maximal ethanol production of 9 g/L was obtained from Jerusalem artichoke inulin at the early stationary phase (around 30 hr), indicating that recombinant S. cerevisiae cells secreting exoinulinase could be used for the simultaneous saccharification of inulin and ethanol fermentation.

• KSBB Journal
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• 제30권6호
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• pp.332-338
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• 2015

The objective of this study was designed to determine the possibility of bioethanol production from wasted medium density fiberboard (wMDF). We were investigated the enzymatic saccharification characteristics using the enzyme (Cellic CTec3) after pretreatment with sodium chlorite. According to the component analysis results, the lignin contents before and after the pretreatment of wMDF (milling using sieve size of $1,000{\mu}m$) was significantly reduced from 31.13% to 4.11%. Therefore, delignification ratio of pretreated wMDF was found to be up to about 87-89% depending on the sieve size. And we were tested to compare the saccharification ratio according to the sieve size of wMDF ($1,000{\mu}m$, $200{\mu}m$), but it was no significance depending on the sieve size. When enzyme dosage was 5% based on the substrate concentration, enzymatic saccharification ratio was obtained up to 70% by maintaining at $50^{\circ}C$ for 72 hours. We could made the substrate concentration of pretreated wMDF ($1,000{\mu}m$) up to 12% and then enzymatic saccharification ratio was 76.8%, also contents of glucose and xylose were analyzed to 77,750 and 14,637 mg/L, respectively.

• 동의생리병리학회지
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• 제21권5호
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• pp.1148-1153
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• 2007

Streptococcus mutans is considered one of the primary etiologic agents of dental caries. we studied the effect of the ethanol extracts of Tribuli fructus (T. fructus) on the growth, biofilm formation, acid production, adhesion and insoluble glucan synthesis of S. mutans. The ethanol extracts of T. fructus showed concentration dependent inhibitory activity against the growth and acid production of S. mutans, and produced significant inhibition at the concentration of 0.025, 0.05, 0.1, 0.2, 0.3, 0.5 mg/ml compared to the control group. In the biofilm assay, the ethanol extracts of T. fructus inhibited formation of biofilm synthesized by S. mutans at the concentration of 0.05 mg/ml. The extracts markedly inhibited S. mutans adherence to HA treated with saliva, and cell adherence was repressed by more than 50% at the concentration 0.05 mg/ml. On the activity of glucosyltransferase which synthesizes water insoluble glucan form sucrose, ethanol extract of T. fructus showed more than 10% inhibition over the concentration of 0.025 mg/ml. Hence, we conclude that T. fructus might be a candidate of anticaries agent. Further studies are necessary to clarify the active constituents of T. fructus responsible for such biomolecular activities.

• Journal of the Korean Wood Science and Technology
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• 제40권4호
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• pp.294-301
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• 2012

본 연구는 농업 부산물인 옥수숫대를 이용하여 옥살산 전처리와 효소가수분해를 통한 에탄올 발효 효율 향상조건을 탐색하였다. 옥살산 전처리 옥수숫대의 효소가수분해는 Accellerase 1000을 이용하였으며, $50^{\circ}C$ 온도조건과 pH 4.5에서 96시간 가수분해하여 가장 높은 단당류 수율인 $64.8g/{\ell}$의 단당류 수율을 나타냈다. 옥수숫대에서 생산된 단당류의 발효에는 Pichia stipitis CBS 6054를 공시균주로 사용하였고, 전처리 옥수숫대 및 효소 투입량이 각각 10~14%와 15 FPU 이었을 때 효율적인 에탄올 생산에 가장 적합한 것으로 판명되었다. 이러한 조건에서 24시간 발효 후에 약 88.2%의 에탄올 전환율에 해당되는 0.45의 에탄올 수율을 얻었다.