Enhanced Ethanol Production through Selective Adsorption in Bacterial Fermentation

R. A. Jones,J. A. Gandier,J. Thibault,F. H. Tezel 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.3

To alleviate the ethanol inhibition of Escherichia coli KO11 (ATCC 55124), during fermentation, online ethanol sequestration was achieved using F-600 activated carbon. Two separate schemes were tested, one involving direct addition of activated carbon to the fermentation flask for the purpose of in-situ adsorption and a second involving an externally located activated carbon packed bed. For the in-situ ethanol adsorption experiments, varying amounts of adsorbent were added to the medium at the start of the fermentation. The addition of the activated carbon in the fermentation broth resulted in increased glucose utilization and ethanol production for all flasks containing activated carbon. For the control flasks, approximately 75% of the available substrate was utilized before the fermentation was inhibited. The entire glucose supply of flasks containing activated carbon was depleted. Ethanol production was also increased from 28 g/L for the control containing no activated carbon to nearly 45 g/L (including the ethanol in the adsorbed phase) for the flasks containing activated carbon. The implementation of an externally located packed bed adsorber for the purpose of on-line ethanol removal was tested over a number of adsorption cycles to evaluate the performance of the adsorption bed and the ethanol productivity. Results indicate that maintaining ethanol fermentation medium concentrations below 20 ~ 30 g/L extends and enhances ethanol productivity. After 3 cycles over a period of 180 h, an additional 80% ethanol was produced when compared to the control experiments, despite the suboptimal acidic pH of the medium.

배양액내 나트륨 및 칼륨 이온 농도가 Saccharomyces cerevisiae의 발효에 미치는 영향

송우용,성현아,신수정 한국펄프·종이공학회 2015 펄프.종이技術 Vol.34 No.1

In bioethanol from acid hydrolysis process, neutralization of acid hydrolyzate is essential step, which resultedin dissolved cations in glucose solution. Impact of cations to Saccharomyces cerevisiae in glucosesolution was investigated focused on ethanol fermentation. Both potassium and sodium cations decreased the ethanol fermentation and glucose to ethanol conversion as potassium or sodium cations. In sodium cation, more than 1.13 N sodium cation in glucose solution led to ethanol production lessthan the oretical yield with severe inhibition. In 1.13 N sodium cation concentration, ethanol fermentation was slowed down to reach the maximum ethanol concentration with 48 h fermentation compared with24 h fermentation in control (no sodium cation in glucose solution). In case of potassium cation, three different levels of potassium led to silimar ethanol concentration even though slight slow down of ethanol fermentation with increasing potassium cation concentration at 12 h fermentation. Sodium cation showed more inhibition than potassium cation as ethanol concentration and glucose consumption by Saccharomyces cerevisiae.

Production of Bioethanol from Sugarcane Bagasse Using NH4OH-H2O2 Pretreatment and Simultaneous Saccharification and Co-fermentation

Zhi-Sheng Zhu,Ming-Jun Zhu,Wan-Xia Xu,Lei Liang 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.2

In this study, we investigated the production of bioethanol from sugarcane bagasse (SCB) using an NH4OH-H2O2 pretreatment and simultaneous saccharification and co-fermentation (SScF). Response surface methodology and a 23 Box-Behnken design were used to evaluate the effect of different liquid mixture concentrations, liquid-tosolid ratios (LSRs) and pretreatment temperatures on the production of ethanol. The liquid mixture concentration and LSR significantly influenced the fermentation efficiency. Based on ridge max analysis, the following pretreatment conditions resulted in a fermentation efficiency of 95.79 ±0.01%: liquid mixture concentration 53%, LSR 28, and a temperature of 63°C. A morphological analysis performed using scanning electron microscopy (SEM) and chemical characterization revealed that these pretreatment conditions were effective in disrupting the sugarcane fibers and removing lignin. Ethanol fermentation with the pretreated SCB using SScF in yeast SHY 07-1 resulted in an ethanol concentration of 14.65 ± 0.17 g/L, an ethanol yield of 0.48± 0.01 g/g, and an ethanol productivity of 0.12 ± 0.01 g/(L/h), which represents increases of 106.02, 89.98, and 107.02%, respectively, over the values obtained from SScF with untreated SCB. In this study, we investigated the production of bioethanol from sugarcane bagasse (SCB) using an NH4OH-H2O2 pretreatment and simultaneous saccharification and co-fermentation (SScF). Response surface methodology and a 23 Box-Behnken design were used to evaluate the effect of different liquid mixture concentrations, liquid-tosolid ratios (LSRs) and pretreatment temperatures on the production of ethanol. The liquid mixture concentration and LSR significantly influenced the fermentation efficiency. Based on ridge max analysis, the following pretreatment conditions resulted in a fermentation efficiency of 95.79 ±0.01%: liquid mixture concentration 53%, LSR 28, and a temperature of 63°C. A morphological analysis performed using scanning electron microscopy (SEM) and chemical characterization revealed that these pretreatment conditions were effective in disrupting the sugarcane fibers and removing lignin. Ethanol fermentation with the pretreated SCB using SScF in yeast SHY 07-1 resulted in an ethanol concentration of 14.65 ± 0.17 g/L, an ethanol yield of 0.48± 0.01 g/g, and an ethanol productivity of 0.12 ± 0.01 g/(L/h), which represents increases of 106.02, 89.98, and 107.02%, respectively, over the values obtained from SScF with untreated SCB.

에탄올 생산 향상을 위한 발효저해물질 제거와 리그닌 유래 발효저해물질이 에탄올 발효에 미치는 영향

엄민 ( Min Um ),신경진 ( Gyeong-jin Shin ),이재원 ( Jae-won Lee ) 한국목재공학회 2016 목재공학 Vol.44 No.3

본 연구에서는 옥살산 전처리 바이오매스의 액상가수분해산물에 포함된 발효저해물질을 전기투석과 XAD 수지 처리하여 제거한 후 에탄올을 생산하였다. 전기투석 과정에서 아세트산은 대부분 제거되었으며(95.6%), 비이온성 발효저해물질(Total phenolic compound: TPC, 5-hydroxymethyl furfural: HMF, furfural)은 XAD 수지 처리에 의해 효과적으로 제거되었다. 전기투석과 XAD 수지 처리된 액상가수분해산물로 발효를 수행한 결과 XAD 수지의 침지시간이 짧을수록 에탄올 생산이 향상되었다. 최대 에탄올 생산은 발효 72시간 후 6.16 g/ℓ로 전기투석 후 액상가수분해산물을 XAD-4 수지에서 5분 침지하였을 때 나타났다. 리그닌 유래 발효저해물질 중 syringaldehyde는 저농도(1 mM, 2 mM)에서 에탄올 생산을 향상시켰으며 5 mM에서는 발효에 부정적인 영향을 주었다. 리그닌 유래 발효저해물질의 시너지효과를 확인하고자 합성배지로 발효를 수행하였으며, Syringaldehyde (1 mM)와 ferulic acid (1 mM) 합성배지를 이용하여 발효를 수행한 결과 syringaldehyde보다 ferulic acid의 영향으로 에탄올 생산이 감소했다. In this study, ethanol was produced from a biomass hydrolysate that had been treated by electrodialysis (ED) and Amberlite XAD resin to remove fermentation inhibitors. Most of the acetic acid (95.6%) was removed during the ED process. Non-ionizable compounds such as total phenolic compounds, 5-hydroxymethyl furfural, and furfural were effectively removed by the XAD resin treatment. Ethanol production was improved when the ED-treated hydrolysate was treated with XAD-4 resin for a short reaction time. The highest ethanol production from ED-treated hydrolysate was 6.16 g/ℓ (after 72 h of fermentation) when the treatment with XAD-4 resin was for 5 min. Among the ligninderived fermentation inhibitors tested, syringaldehyde in low concentrations (1 and 2 mM) in the hydrolysate increased ethanol production, whereas a high concentration (5 mM) inhibited the ethanol production process. A synthetic medium containing syringaldehyde and ferulic acid was prepared to investigate the synergistic effect of inhibitors on ethanol fermentation. Ethanol production decreased in the mixture of 1 mM syringaldehyde and 1 mM ferulic acid, implying that the effect of ferulic acid on ethanol fermentation is comparable to that of syringaldehyde.

Methane Fermentation of Artificial Food Waste using Biological Ethanol Fermentation Pretreatment

( Yasunori Kosaki ),( Munetaka Ishikawa ) 한국폐기물자원순환학회(구 한국폐기물학회) 2015 한국폐기물자원순환학회 3RINCs초록집 Vol.2015 No.-

The effect of pretreatment by saccharification and ethanol fermentation on methane fermentation of food waste containing a high density of carbohydrates was studied. The ratio of methane and carbon dioxide in biogas from carbohydrates is the same stoichiometrically even if pretreatment is performed. The methane ratio in methane fermentation increases to 75% when the carbohydrate is converted to ethanol through pretreatment.In addition, this method is expected to control the generation of VFA (Volatile fatty acids) composed of three or more carbon atoms, by conversion to smaller molecules such as ethanol. To verify these effects, batch experiments were performed using artificial food waste as a substrate. It was found that the methane concentration in the biogas increases by about 10% without ethanol inhibiting the activation of biomass Further, information on the possibility of high-load operations by suppressing VFA generation was also obtained.

배양액내 나트륨과 칼륨의 농도가 고온 발효 균주 Kluyveromyces marxianus의 발효에 미치는 영향

송우용(Woo-Yong Song),신수정(Soo-Jeong Shin) 한국펄프·종이공학회 2015 펄프.종이기술 Vol.47 No.3

In acid hydrolysis process of biomass saccharification. neutralization of acid hydrolyzate is essential step, which resulted in dissolved cations in glucose solution. Impact of cations to Kluyveromyces marxianus in glucose solution was investigated focused on ethanol fermentation. Either potassium or sodium cations decreased the ethanol fermentation and glucose to ethanol conversion. Glucose consumption by K. marxianus was delayed by increasing potassium cation concentration as completely consumed within 12 h in potassium cation 0.46 mol and 0.92 mol but within 24 h in potassium cation 1.38 mol. Also, ethanol fermentation process was slowed down with increasing concentration of the potassium sulfate. Fermentation of glucose solution to ethanol was more inhibited by sodium cation than potassium cation in glucose solution. Glucose was completely consumed within 24 h in sodium cation 0.95 mol. but at 1.90 mol or 2.84 mol in sodium cation could not finish the fermentation within 48 hour. Ethanol concentration was 22.26 g/L at low sodium cation in glucose solution with complete fermentation within 24 h. With increasing sodium cation in glucose solution, final ethanol concentration was reached at 14.10 g/L (sodium cation con) and 0.21 g/L (sodium cation con), which meant delaying of fermentation by sodium cations.

배양액내 나트륨과 칼륨의 농도가 고온 발효 균주 Kluyveromyces marxianus의 발효에 미치는 영향

송우용,신수정 한국펄프·종이공학회 2015 펄프.종이技術 Vol.39 No.3

In acid hydrolysis process of biomass saccharification. neutralization of acid hydrolyzate is essential step, which resulted in dissolved cations in glucose solution. Impact of cations to Kluyveromyces marxianus in glucose solution was investigated focused on ethanol fermentation. Either potassium or sodium cations decreased the ethanol fermentation and glucose to ethanol conversion. Glucose consumption by K. marxianus was delayed by increasing potassium cation concentration as completely consumed within 12 h in potassium cation 0.46 mol and 0.92 mol but within 24 h in potassium cation 1.38 mol. Also, ethanol fermentation process was slowed down with increasing concentration of the potassium sulfate. Fermentation of glucose solution to ethanol was more inhibited by sodium cation than potassium cation in glucose solution. Glucose was completely consumed within 24 h in sodium cation 0.95 mol. but at 1.90 mol or 2.84 mol in sodium cation could not finish the fermentation within 48 hour. Ethanol concentration was 22.26 g/L at low sodium cation in glucose solution with complete fermentation within 24 h. With increasing sodium cation in glucose solution, final ethanol concentration was reached at 14.10 g/L (sodium cation con) and 0.21 g/L (sodium cation con), which meant delaying of fermentation by sodium cations.

Bacterial Contamination and Its Effects on Ethanol Fermentation

Chang, In Seop,Kim, Byung Hong,Shin, Pyong Kyun,Lee, Wan Kyu 한국미생물 · 생명공학회 1995 Journal of microbiology and biotechnology Vol.5 No.6

Samples were collected from a commercial ethanol production plant to enumerate the bacterial contamination in each step of a starch based ethanol production process. Though the slurry of raw material used in the process carried bacteria with various colony morphology in the order of 10^4 per ㎖, only the colonies of white and circular form survived and propagated through the processes to the order of 10^8 per ㎖ at the end of fermentation. Almost all of the bacterial isolates from the fermentation broth were lactic acid bacteria. Heterofermentative Lactobacillus fermentum and L. salivarius, and a facultatively heterofermentative L. casei were major bacteria of an ethanol fermentation. In a batch fermentation L. fermentum was more detrimental than L. casei to ethanol fermentation. In a cell-recycled fermentation, ethanol productivity of 5.72 g l^-1 h^-1 was obtained when the culture was contaminated by L. fermentum, whilst that of the pure culture was 9.00 g l^-1 h^-1. Similar effects were observed in a cell-recycled ethanol fermentation inoculated by fermentation broth collected from an industrial plant, which showed a bacterial contamination at the level of 10^8 cells per ㎖.

배양액내 나트륨 및 칼륨 이온 농도가 Saccharomyces cerevisiae의 발효에 미치는 영향

송우용(Woo-Yong Song),성현아(Hyun-A Seung),신수정(Soo-Jeong Shin) 한국펄프·종이공학회 2015 펄프.종이기술 Vol.47 No.1

In bioethanol from acid hydrolysis process, neutralization of acid hydrolyzate is essential step, which resulted in dissolved cations in glucose solution. Impact of cations to Saccharomyces cerevisiae in glucose solution was investigated focused on ethanol fermentation. Both potassium and sodium cations decreased the ethanol fermentation and glucose to ethanol conversion as potassium or sodium cations. In sodium cation, more than 1.13 N sodium cation in glucose solution led to ethanol production less than theoretical yield with severe inhibition. In 1.13 N sodium cation concentration, ethanol fermentation was slowed down to reach the maximum ethanol concentration with 48 h fermentation compared with 24 h fermentation in control (no sodium cation in glucose solution). In case of potassium cation, three different levels of potassium led to silimar ethanol concentration even though slight slow down of ethanol fermentation with increasing potassium cation concentration at 12 h fermentation. Sodium cation showed more inhibition than potassium cation as ethanol concentration and glucose consumption by Saccharomyces cerevisiae.

Saccharomyces cerevisiae를 이용한 반복 유가식 ethanol 발효에서 ethanol 생산량을 증가를 위한 운전 전략

이상은(Sang-Eun Lee),서현범(Hyeon-Beom Seo),권민철(Min Cheol Kwon),이현용(Hyeon-Yong Lee),정경환(Kyung-Hwan Jung) 한국생물공학회 2010 KSBB Journal Vol.25 No.2

S. cerevisiae ATCC 24858을 이용한 ethanol 생산에서, aeration 효과를 ethanol 수율, specific ethanol production rate, ethanol 생산성 측면에서 분석하여, 반복 유가식 공정전략을 설계하였다. Ethanol 수율과 ethanol 생산성은 공기를 0.33 vvm 넣었을 때, 공기를 넣지 않고 배양한 것에 비하여 더 큰 값을 보였고, 24시간 마다 배지를 교체한 배양이 36시간 마다 배지를 교체한 배양 보다 더 큰 값을 보였다. 총 ethanol 생산량 값이 가장 큰 경우는 0.33 vvm의 공기를 넣고, 배지를 24시간마다 완전히 갈아주었을 때이고, 이때 가장 많은 703.8 g의 ethanol이 생산되었다. We designed the optimal operational strategy in repeated fed-batch ethanol fermentation using Sacchromyces cerevisiae ATCC 24858 in views of ethanol yield, specific ethanol production rate, and ethanol productivity, when the aeration rate were controlled at 0.0 and 0.33 vvm. Coincidentally, the time intervals of withdrawal-fill of culture medium (24 and 36 h) were investigated. Ethanol yield and ethanol productivity when the aeration was carried out at 0.33 vvm were superior to those when the aeration was not carried out. Additionally, those parameters when the time interval of withdrawal-fill of culture medium was 24 h were superior to those when time interval of withdrawal-fill of culture medium was 36 h. The total ethanol production reached at the greatest value, 703.8 g-ethanol, when the aeration was carried out at 0.33 vvm and the time interval of withdrawal-fill of culture medium was 24 h. In this study, we verified experimentally the necessity of designing the operational strategy for increasing ethanol production in terms of aeration rate and time interval of withdrawal-fill of culture medium in the repeated fed-batch ethanol fermentation.