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Dilute acid pretreatment of barley straw and its saccharification and fermentation
Special Abstracts / Journal of Biotechnology 150S (2010) S1–S576
[P-B.14] Dilute acid pretreatment of barley straw and its saccharification and fermentation Sung Bong Kim 1,3,4,∗ , Ja Hyun Lee 1,3,4 , Sang Jun Lee 1,3,4 , Eun Ji Jang 1,3,4 , Kyeong Keun Oh 2,3,4 , Seung Wook Kim 1,3,4 1
Korea University, Korea, Republic of Dankuk University, Korea, Republic of 3 Kyonggi University, Korea, Republic of 4 Kwangwoon University, Korea, Republic of Keywords: Dilute acid pretreatment; Saccharification; Fermentation; Barley straw 2
Pretreatment of lignocellulosic biomass is a critical process of whole saccharification process because of its rigid and hard degradable structure. A number of researchers have been studied on pretreatment of lignocellulosic biomass and this effort induced that pretreatment area is improved to affordable level. Dilute acid pretreatment (DAP) solubilized hemicellulosic compounds, one of major components of lignocellulosic biomass. Several factors affect solubility of hemicellulose in DAP. The concentration of acid, reaction time and temperature are revealed as the most important factors. In this study, optimization of these factors using response surface method (RSM) on Korean barley straw was conducted and saccharification of pretreated barley straw and fermentation of both solubilized hemicellulose and enzymatic hydrolysates was also carried out. Optimization was performed with 0.16–1.84% of sulfuric acid, 10–20 min of reaction time and 116∼183 of temperature. Celluclast (60 FPU) and Novozyme188 (10 CBU) was used for saccharification, according to NREL standard procedure (50 temperature, 0.05 M citrate buffer (pH 4.8), 150 rpm agitation speed and 20 g/L substrate concentration). RSM results show the optimal conditions as follow; 1.1% of sulfuric acid, 16 min of reaction time and 140 . Conversion yield in saccharification process was about 65% (7.86 g/L of glucose) obtained from 20 g/L of pretreated barley straw. Also, fermentation of both the glucose after saccharification and xylose solution solubilized by DAP was performed using Saccharomyces cerevisiae and Pitchia stipitis under the condition of 30 , 200 rpm for 12 h. doi:10.1016/j.jbiotec.2010.08.367 [P-B.15] Hydrogen production by bacterial consortia selected from lake sediments S. Romano ∗ , P. Paganin, C. Varrone, S. Tabacchioni, L. Chiarini ENEA - Plant Genetics and Genomics section, Italy Keywords: Hydrogen; Sediments; Clostridium bifermentans; Dark fermentation Bio-hydrogen holds the promise for a substantial contribution to the future renewable energy demands. It seems particularly suitable for relatively small-scale, decentralized systems, integrated with agricultural and industrial activities or waste processing facilities. Biohydrogen is considered as an important key to a sustainable world power supply and is currently being seen as the versatile fuel of the future, with the potential to replace fossil fuels. In order to evaluate the hydrogen production ability of the bacterial community thriving in lake sediments of Averno (Naples) batch fermentation experiment were carried out in semisynthetic
S141
medium at 28 ◦ C. This kind of inoculum was chosen because Averno lake is an eutrophic ecosystem with high bacterial biodiversity and intense fermentative processes in the depth layer. Prior to incubation cultures were heat-treated at 100 ◦ C for 5 minutes to inhibit non-sporigen bacteria. The fermentation experiments were carried out for two weeks and samples were collected on the 3rd and 7th day of each weeks to analyze (i) hydrogen, butyric acid, acetic acid, propionic acid, ethanol, methane, glucose by GC and HPLC; (ii) species composition of bacterial consortia by DGGE and 16S rDNA sequencing. Data suggest that Averno lake sediment is a good inoculum for hydrogen production. We obtained maximum hydrogen yield of about 2 mol H2 /mol Gluc in heat-treated cultures whereas control cultures had lower yield and unstable temporal production. In heat-treated cultures hydrogen was apparently released through Ethanol type Fermentation, which couples hydrogen, ethanol and acetic acid production. Probably this kind of metabolism was due to Clostridium bifermentans, which is the dominant species only in the heat-treated cultures. At present we are evaluating the use of these heat-selected bacterial communities for the simultaneous production of hydrogen and ethanol from organic solid wastes. doi:10.1016/j.jbiotec.2010.08.368 [P-B.16] Use of mixed substrate composed of organic solid wastes and energetic crop plants (Jerusalem artichoke) for the combined production of hydrogen, ethanol and methane in a two-stage fermentation process T. Pepè Sciarria ∗ , S. Romano, A. Correnti ENEA C.R. Casaccia, Italy Keywords: Hydrogen; Organic fraction of municipal wastes; Jerusalem artichoke; Ethanol In the frame of the development of new integrated processes for the production of renewable fuels from fermentable wastes and biomass, we investigated the feasibility on a laboratory scale of a two-stage fermentation process for the production of hydrogen, ethanol and methane; as substrate we used the organic fraction of municipal solid wastes (OSW) together with biomass derived from the plant Helianthus tuberosus (Jerusalem artichoke) which has a high content of sugars, mainly inuline and fructose. Jerusalem artichoke has been cultivated in a field in the surroundings of a landfill site where no food crops are allowed. In the first fermentation stage, selected bacterial consortia produce hydrogen and ethanol through the alcoholic fermentation using OSW and J. artichoke stalks as substrate, while in the second stage methane is produced by acetoclastic archaeobacteria using the effluent of the first fermentation as substrate, where acetic acid is the major carbon source. Bacterial consortia for both fermentation stages have been isolated from the sediments of an eutrophic lake, where hydrogen-producing bacterial communities have been widely investigated. As far as the first fermentation stage is concerned, highest hydrogen production was achieved when equal volumes of OSW and J. artichoke (1:1, v/v) were mixed and used as substrate. Inoculum (20%, v/v) was prepared by inoculating sterile OSW with the above-mentioned selected consortia. In the first fermentation stage, Clostridium bifermentans and C. butyrricum were the dominant species in the consortium. It is conceivable that the former bacterium is the major responsible for the production of ethanol while both bacteria are capable of producing hydrogen. Future research activities will concern the full set up of the second fermentation stage and also the designing and building of a small pilot plant, in order to achieve a preliminary evalu-
[P-B.14] Dilute acid pretreatment of barley straw and its saccharification and fermentation Sung Bong Kim 1,3,4,∗ , Ja Hyun Lee 1,3,4 , Sang Jun Lee 1,3,4 , Eun Ji Jang 1,3,4 , Kyeong Keun Oh 2,3,4 , Seung Wook Kim 1,3,4 1
Korea University, Korea, Republic of Dankuk University, Korea, Republic of 3 Kyonggi University, Korea, Republic of 4 Kwangwoon University, Korea, Republic of Keywords: Dilute acid pretreatment; Saccharification; Fermentation; Barley straw 2
Pretreatment of lignocellulosic biomass is a critical process of whole saccharification process because of its rigid and hard degradable structure. A number of researchers have been studied on pretreatment of lignocellulosic biomass and this effort induced that pretreatment area is improved to affordable level. Dilute acid pretreatment (DAP) solubilized hemicellulosic compounds, one of major components of lignocellulosic biomass. Several factors affect solubility of hemicellulose in DAP. The concentration of acid, reaction time and temperature are revealed as the most important factors. In this study, optimization of these factors using response surface method (RSM) on Korean barley straw was conducted and saccharification of pretreated barley straw and fermentation of both solubilized hemicellulose and enzymatic hydrolysates was also carried out. Optimization was performed with 0.16–1.84% of sulfuric acid, 10–20 min of reaction time and 116∼183 of temperature. Celluclast (60 FPU) and Novozyme188 (10 CBU) was used for saccharification, according to NREL standard procedure (50 temperature, 0.05 M citrate buffer (pH 4.8), 150 rpm agitation speed and 20 g/L substrate concentration). RSM results show the optimal conditions as follow; 1.1% of sulfuric acid, 16 min of reaction time and 140 . Conversion yield in saccharification process was about 65% (7.86 g/L of glucose) obtained from 20 g/L of pretreated barley straw. Also, fermentation of both the glucose after saccharification and xylose solution solubilized by DAP was performed using Saccharomyces cerevisiae and Pitchia stipitis under the condition of 30 , 200 rpm for 12 h. doi:10.1016/j.jbiotec.2010.08.367 [P-B.15] Hydrogen production by bacterial consortia selected from lake sediments S. Romano ∗ , P. Paganin, C. Varrone, S. Tabacchioni, L. Chiarini ENEA - Plant Genetics and Genomics section, Italy Keywords: Hydrogen; Sediments; Clostridium bifermentans; Dark fermentation Bio-hydrogen holds the promise for a substantial contribution to the future renewable energy demands. It seems particularly suitable for relatively small-scale, decentralized systems, integrated with agricultural and industrial activities or waste processing facilities. Biohydrogen is considered as an important key to a sustainable world power supply and is currently being seen as the versatile fuel of the future, with the potential to replace fossil fuels. In order to evaluate the hydrogen production ability of the bacterial community thriving in lake sediments of Averno (Naples) batch fermentation experiment were carried out in semisynthetic
S141
medium at 28 ◦ C. This kind of inoculum was chosen because Averno lake is an eutrophic ecosystem with high bacterial biodiversity and intense fermentative processes in the depth layer. Prior to incubation cultures were heat-treated at 100 ◦ C for 5 minutes to inhibit non-sporigen bacteria. The fermentation experiments were carried out for two weeks and samples were collected on the 3rd and 7th day of each weeks to analyze (i) hydrogen, butyric acid, acetic acid, propionic acid, ethanol, methane, glucose by GC and HPLC; (ii) species composition of bacterial consortia by DGGE and 16S rDNA sequencing. Data suggest that Averno lake sediment is a good inoculum for hydrogen production. We obtained maximum hydrogen yield of about 2 mol H2 /mol Gluc in heat-treated cultures whereas control cultures had lower yield and unstable temporal production. In heat-treated cultures hydrogen was apparently released through Ethanol type Fermentation, which couples hydrogen, ethanol and acetic acid production. Probably this kind of metabolism was due to Clostridium bifermentans, which is the dominant species only in the heat-treated cultures. At present we are evaluating the use of these heat-selected bacterial communities for the simultaneous production of hydrogen and ethanol from organic solid wastes. doi:10.1016/j.jbiotec.2010.08.368 [P-B.16] Use of mixed substrate composed of organic solid wastes and energetic crop plants (Jerusalem artichoke) for the combined production of hydrogen, ethanol and methane in a two-stage fermentation process T. Pepè Sciarria ∗ , S. Romano, A. Correnti ENEA C.R. Casaccia, Italy Keywords: Hydrogen; Organic fraction of municipal wastes; Jerusalem artichoke; Ethanol In the frame of the development of new integrated processes for the production of renewable fuels from fermentable wastes and biomass, we investigated the feasibility on a laboratory scale of a two-stage fermentation process for the production of hydrogen, ethanol and methane; as substrate we used the organic fraction of municipal solid wastes (OSW) together with biomass derived from the plant Helianthus tuberosus (Jerusalem artichoke) which has a high content of sugars, mainly inuline and fructose. Jerusalem artichoke has been cultivated in a field in the surroundings of a landfill site where no food crops are allowed. In the first fermentation stage, selected bacterial consortia produce hydrogen and ethanol through the alcoholic fermentation using OSW and J. artichoke stalks as substrate, while in the second stage methane is produced by acetoclastic archaeobacteria using the effluent of the first fermentation as substrate, where acetic acid is the major carbon source. Bacterial consortia for both fermentation stages have been isolated from the sediments of an eutrophic lake, where hydrogen-producing bacterial communities have been widely investigated. As far as the first fermentation stage is concerned, highest hydrogen production was achieved when equal volumes of OSW and J. artichoke (1:1, v/v) were mixed and used as substrate. Inoculum (20%, v/v) was prepared by inoculating sterile OSW with the above-mentioned selected consortia. In the first fermentation stage, Clostridium bifermentans and C. butyrricum were the dominant species in the consortium. It is conceivable that the former bacterium is the major responsible for the production of ethanol while both bacteria are capable of producing hydrogen. Future research activities will concern the full set up of the second fermentation stage and also the designing and building of a small pilot plant, in order to achieve a preliminary evalu-