• Journal of Microbiology and Biotechnology
• /
• v.22 no.1
• /
• pp.107-113
• /
• 2012

To develop a practical and cost-effective medium for bioethanol production from the hydrolysate of seaweed Sargassum sagamianum, we investigated the feasibility and performance of bioethanol production in CSL (corn-steep liquor)-containing medium, where yeast Pichia stipitis was used and the repeated batch was carried out in a surface-aerated fermentor. The optimal medium replacement time during the repeated operation was determined to be 36 h, and the surface aeration rates were 30 and 100 ml/min. Under these conditions, the repeated-batch operation was successfully carried out for 6 runs (216 h), in which the maximum bioethanol concentrations reached about 11-12 g/l at each batch operation. These results demonstrated that bioethanol production could be carried out repeatedly and steadily for 216 h. In these experiments, the total cumulative bioethanol production was 57.9 g and 58.0 g when the surface aeration rates were 30 ml/min and 100 ml/min, respectively. In addition, the bioethanol yields were 0.43 (about 84% of theoretical value) and 0.44 (about 86% of theoretical value) when the surface aeration rates were 30 ml/min and 100 ml/min, respectively. CSL was successfully used as a medium ingredient for the bioethanol production from the hydrolysate of seaweed Sargassum sagamianum, indicating that this medium may be practical and cost-effective for bioethanol production.

• KSBB Journal
• /
• v.25 no.3
• /
• pp.283-288
• /
• 2010

We investigated the feasibility of bioethanol production from hydrolysate of brown seaweed Sargassum sagamianum. Prior to bioethanol production using yeasts, six yeast strains were compared and the best ones in terms of the ethanol production levels were selected. Pichia stipitis ATCC 7126, Pichia stipitis ATCC 58784, and Pichia stipitis ATCC 58376 were superior to others in terms of ethanol production. These yeast strains were used for producing bioethanol by the shaking bottle culture and the fermentor culture. Out of approximately 30 g/L reducing sugar, about 3~6 g/L and 4~7 g/L bioethanol were produced in the bottle culture and the fermentor one, respectively. Furthermore, it was observed that around 12~28 g-bioethanol was produced from 1 kilogram of Sargassum sagamianum. Compared with those previously published, these data were almost three to eight times higher in value.

• KSBB Journal
• /
• v.25 no.4
• /
• pp.401-407
• /
• 2010

We established a strategy for bioethanol production using the hydrolysate of rape stem, in which the inhibitor cocktail was added intentionally. The final goal of this study was to circumvent the detoxification process when the hydrolysate of lignocelluloisic biomass contained the toxic substances in high concentration. When six yeast strains were examined, Sacchromyces cerevisiae ATCC 96581 and Pichia stipitis CBS 7126 were relatively resistant to inhibitor cocktail. Then, using strains 96581 and 7126, we designed a process strategy for bioethanol production, assuming that the concentration of toxic substance in the hydrolysate of rape stem was remarkably high. When strains 96581 and 7126 were inoculated simultaneously, it was observed that strain 7126 produced bioethanol as well as strain 96581, although the concentration of inhibitor cocktail was 18.2% (v/v). Finally, throughout this co-cultivation of strains 96581 and 7126, bioethanol was produced about 6.0 (g/L), and bioethanol yield reached at 0.4 (g-bioethanol/g-reducing sugar) (78.4% of theoretical value).

• Mycobiology
• /
• v.37 no.2
• /
• pp.133-140
• /
• 2009

To optimally convert corn hull, a byproduct from corn processing, into bioethanol using Pachysolen tannophlius, we investigated the optimal conditions for hydrolysis and removal of toxic substances in the hydrolysate via activated carbon treatment as well as the effects of this detoxification process on the kinetic parameters of bioethanol production. Maximum monosaccharide concentrations were obtained in hydrolysates in which 20 g of corn hull was hydrolyzed in 4% (v/v) $H_2SO_4$. Activated carbon treatment removed 92.3% of phenolic compounds from the hydrolysate. When untreated hydrolysate was used, the monosaccharides were not completely consumed, even at 480 h of culture. When activated carbon.treated hydrolysate was used, the monosaccharides were mostly consumed at 192 h of culture. In particular, when activated carbon-treated hydrolysate was used, bioethanol productivity (P) and specific bioethanol production rate ($Q_p$) were 2.4 times and 3.4 times greater, respectively, compared to untreated hydrolysate. This was due to sustained bioethanol production during the period of xylose/arabinose utilization, which occurred only when activated carbon-treated hydrolysate was used.

• KSBB Journal
• /
• v.26 no.4
• /
• pp.311-316
• /
• 2011

We investigated the optimal surface aeration rate during bioethanol production from the hydrolysate of seaweed Sargassum sagamianum using Pichia stipitis. It was observed that, when the working volume was 880 mL in 2.5-L lab-fermentor, the surface aeration rates of 30 to 100 mL/min were the optimal values for bioethanol production, in which this surface aeration rate corresponded to less than 0.05 (1/min) as the oxygen transfer rate coefficient ($k_La$). In addition, during repeated-batch operation was carried out, we examined whether those surface aeration rates were the optimal for bioethanol production. It was also observed that the surface aeration rates of 30 to 100 mL/min in the working volume of 880 mL were the optimal values in terms of the cumulative bioethanol producrion and bioethanol yield. On the basis of the oxygen transfer rate coefficient it is probable that those surface aeration rates will be applied to the large-scale bioethanol production from the hydrolysate of seaweed Sargassum sagamianum.

• Journal of Microbiology and Biotechnology
• /
• v.21 no.1
• /
• pp.109-114
• /
• 2011

In this study, we investigated the feasibility of producing bioethanol from the hydrolysate of rape stem. Specifically, the most ideal yeast strain was screened, and the microaeration was performed by surface aeration on a liquid medium surface. Among the yeast strains examined, Pichia stipitis CBS 7126 displayed the best performance in bioethanol production during the surface-aerated fermentor culture. Pichia stipitis CBS 7126 produced maximally 9.56 g/l of bioethanol from the initial total reducing sugars (about 28 g/l). The bioethanol yield was 0.397 (by the DNS method). Furthermore, this controlled surface aeration method holds promise for use in the bioethanol production from the xylose-containing lignocellulosic hydrolysate of biomass.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.10
• /
• pp.1460-1471
• /
• 2013

Microalgal biofuel production from wastewater has economic and environmental advantages. This article investigates the lipid production from high chemical oxygen demand (COD) bioethanol wastewater without dilution or additional nutrients, using a newly isolated heterotrophic microalga, Chlorella vulgaris LAM-Q. To enhance lipid accumulation, the combined effects of important operational parameters were studied via response surface methodology. The optimal conditions were found to be temperature of $22.8^{\circ}C$, initial pH of 6.7, and inoculum density of $1.2{\times}10^8cells/ml$. Under these conditions, the lipid productivity reached 195.96 mg/l/d, which was markedly higher than previously reported values in similar systems. According to the fatty acid composition, the obtained lipids were suitable feedstock for biodiesel production. Meanwhile, 61.40% of COD, 51.24% of total nitrogen, and 58.76% of total phosphorus were removed from the bioethanol wastewater during microalgal growth. In addition, 19.17% of the energy contained in the wastewater was transferred to the microalgal biomass in the fermentation process. These findings suggest that C. vulgaris LAM-Q can efficiently produce lipids from high-concentration bioethanol wastewater, and simultaneously performs wastewater treatment.

• Advances in Energy Research
• /
• v.4 no.1
• /
• pp.69-86
• /
• 2016

The quest to reduce the level of overdependence on fossil fuel product and to provide all required information on proven existing alternatives for renewable energy has resulted into rapid growth of research globally to identify efficient alternative renewable energy sources and the process technologies that are sustainable and environmentally friendly. The present study is aimed at production and characterization of bioethanol produced from sugarcane juice using a $2^4$ factorial design investigating the effect of four parameters (reaction temperature, time, concentration of bacteria used and amount of substrate). The optimum bioethanol yield of 19.3% was achieved at a reaction temperature of $30^{\circ}C$, time of 72 hours, yeast concentration of 2 g and 300 g concentration of substrate (sugarcane juice). The result of statistical analysis of variance shows that the concentration of yeast had the highest effect of 7.325 and % contribution of 82.72% while the substrate concentration had the lowest effect and % contribution of -0.25 and 0.096% respectively. The bioethanol produced was then characterized for some fuel properties such as flash point, specific gravity, cloud point, pour point, sulphur content, acidity, density and kinematic viscosity. The results of bioethanol characterization conform to American society for testing and materials (ASTM) standard. Hence, sugarcane juice is a good and sustainable feedstock for bioethanol production in Nigeria owing relative abundance, cheap source of supply and available land for large scale production.

• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.6
• /
• pp.697-703
• /
• 2017

This study investigated the high-efficient process for bioethanol from barley by various condition. First, higher concentrations of ethanol could be produced without loss of yield by using reducing water consumption. This is because it could prevent to increase viscosity despite reducing water consumption. Second, the ethanol yield could be improved by using reducing particle size of biomass (increase of enzyme reactive surface). Third, The addition of protease could have a considerable effect on yield of fermentation, which provides nutrients to the yeast. This results showed that bioethanol production would provide efficient ethanol production and lower production costs.

• Bulletin of Food Technology
• /
• v.23 no.2
• /
• pp.220-223
• /
• 2010

최근에 대두되고 있는 환경오염문제라던가 원유의 의존도 측면에서 볼 때 삼림자원 바이오매스를 원료로 한 bioethanol의 중요성이 높아지고 있다. 현재 bioethanol 제조는 효모 등을 이용한 발효법으로 대부분 제조되고 있지만 효소를 이용한 bioethanol 제조를 할 수 있다면 효율이 높은 ethanol생산과 이 반응에서 나오는 반응산물을 간단하게 정제할 수가 있게 된다. 또한 내열성 효소를 이용하여 고온 조건에서 효소반응을 하게 되면 효소반응과 반응산물 증류를 동시에 진행할 수 있으며, 반응속도의 향상과 잡균의 혼입억제 등 여러가지 이점이 기대된다. 본 고에서는 내열성 효소를 이용한 cellulose와 hemicellulose로부터 ethanol 제조 연구에 대한 개요를 살펴보기로 한다.