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Hollow fiber membrane fermentor to convert synthesis gas into bioethanol
S150
Special Abstracts / Journal of Biotechnology 150S (2010) S1–S576
and the medium mixtures were used for cultivation of the both strains under mixotrophic growth condition. Growth was monitored and the algal biomass was harvested at early stationary phase and sequent steps of cell disruption by osmotic shock method using 10% NaCl coupling with chemical extraction (1:1, v/v chloroformmethanol) were undertaken. Finally, total lipids obtained were used for biodiesel production via transesterification reaction. In addition, biodiesel product was also tested in properties following to the standard of American Society for Testing and Materials (ASTM). doi:10.1016/j.jbiotec.2010.08.388
Fig. 1. Schematic diagram of hollow fiber membrane fermentor.
[P-B.36] Hollow fiber membrane fermentor to convert synthesis gas into bioethanol Y.-K. Kim ∗ , K.-M. Ahn Hankyong National University, Korea, Republic of Keywords: Hollow fiber membrane fermentor; Synthesis gas; Bioethanol Since the big jump in oil prices, the development of sustainable and renewable energy sources, such as biofuel including bioethanol and biodiesel, has been a major focus in scientific research. Synthesis gas is obtained by thermal gasification of coal, biomass, or waste organic material, and it contains carbon monoxide, carbon dioxide, hydrogen, nitrogen, methane, and other trace components. Synthesis gas can be converted into bioproducts, including methane, acetic acid, butyric acid, ethanol, and butanol by anaerobic bioprocesses. In anaerobic fermentations of synthesis-gas, the rate-limiting step, which is a barrier to make commercial process, is gas-to-liquid mass transfer, due to extremely low solubility. In conventional stirred tank bioreactors, common approach used to enhance gas-to-liquid mass transfer rate is to make large interfacial area per unit gas volume by increasing the agitator’s power-to-volume ratio or using microbubble disperser. However, this approach is not economical for the large commercial-scale bioreactors, due to excessive power costs. In this study, bioprocess was developed to produce ethanol from CO, CO2 , and H2 by using Clostridium ljungdahlii (ATCC 55383). Scheme of biological reaction is as follows. 6CO + 3H2 O → CH3 CH2 OH + 4CO2 6H2 + 2CO2 → CH3 CH2 OH + 3H2 O The composition of gas substrate was 55% nitrogen, 20% carbon monoxide, 20% carbon dioxide, and 5% hydrogen, based on the composition of common synthesis gas. Anaerobic bioconversion reaction was successfully accomplished to produce ethanol in fermentor at a temperature of 37 ◦ C, and product composition was analyzed by using gas chromatography. Bundle of hollow fiber membranes were installed in bioreactor to supply gas substrate as shown in Fig. 1. Bubbles passed through membrane have microscale size, and slight positive pressure was applied to make long residence time due to attachment of bubbles on membrane surface. Using this operating method, gas substrate supply rate was controlled to same as substrate uptake rate. That resulted in the minimization of gas supply and the removal of recirculation of gas substrate in bioreactor. A proposed bioreaction process was successfully used to produce ethanol from synthesis gas.
Acknowledgement: This research was performed for the New & Renewable Energy R&D Program, funded by the Ministry of Knowledge Economy of Korea. doi:10.1016/j.jbiotec.2010.08.389 [P-B.37] Structural and biochemical approaches to design a synthetic agarolytic pathway: From agar to d-galactose and anhydro-lgalactose S. Lee 1,2,3 , K.H. Kim 1,2,3,∗ , I.-G. Choi 1,2,3 1
Korea University, Korea, Republic of University of California at Berkeley, United States 3 California Institute of Technology, United States Keywords: Agarolytic pathway; Neoagarobiose Agarases; Red algae 2
hydrolase;
Bioenergy production from marine biomass (e.g. macroalgae) has been recognized as an alternative route to overcome disadvantages of using land plant biomass. Among macroalgal biomass, red algae have been highlighted for the production of the sustainable biofuels and its major component is the agar polysaccharides. Many agarase families such as glycoside hydrolase (GH) 16, 50 and 86 families are involved in the microbial agarolytic system. With the synergistic action of these enzymes, agar is degraded into its end product (a disaccharide unt, neoagarobiose). This end product is assumed to be converted into two mono-sugars, d-galactose (GAL) and anhydro-l-galactose (AHG), which are metabolized by being integrated into the central metabolic pathway in agarolytic microbes. Although a few reports on the hydrolytic activity of neoagarobiose have been known, neither related gene nor its molecular information has been available yet. Here, we identified and cloned novel neoagarobiose hydrolase (NABH) enzymes from three kinds of agarolytic microorganisms. Among them, we determined atomic structure of NABH at 2.0 A˚ resolution from Saccharophagus degradans 2∼40 with or without GAL. We compared the atomic structure of agarases (e.g. GH 16) and NABH involved in agarolytic pathway. These atomic structures gave us clue to understand the enzymatic mechanism and evolution of these enzymes, which can provide a functional protein design principle. In addition, we designed an in vitro agarolytic system by obtaining several active agarases from the cloning of GH 16 and 50 family proteins. From the system, we tested a synthetic process for the deconstruction of agar biomass. We suggest that the synthetic process has potential for the efficient bioenergy production from red algal biomass by implementing a biomass deconstruction or consolidated bioprocess. doi:10.1016/j.jbiotec.2010.08.390
Special Abstracts / Journal of Biotechnology 150S (2010) S1–S576
and the medium mixtures were used for cultivation of the both strains under mixotrophic growth condition. Growth was monitored and the algal biomass was harvested at early stationary phase and sequent steps of cell disruption by osmotic shock method using 10% NaCl coupling with chemical extraction (1:1, v/v chloroformmethanol) were undertaken. Finally, total lipids obtained were used for biodiesel production via transesterification reaction. In addition, biodiesel product was also tested in properties following to the standard of American Society for Testing and Materials (ASTM). doi:10.1016/j.jbiotec.2010.08.388
Fig. 1. Schematic diagram of hollow fiber membrane fermentor.
[P-B.36] Hollow fiber membrane fermentor to convert synthesis gas into bioethanol Y.-K. Kim ∗ , K.-M. Ahn Hankyong National University, Korea, Republic of Keywords: Hollow fiber membrane fermentor; Synthesis gas; Bioethanol Since the big jump in oil prices, the development of sustainable and renewable energy sources, such as biofuel including bioethanol and biodiesel, has been a major focus in scientific research. Synthesis gas is obtained by thermal gasification of coal, biomass, or waste organic material, and it contains carbon monoxide, carbon dioxide, hydrogen, nitrogen, methane, and other trace components. Synthesis gas can be converted into bioproducts, including methane, acetic acid, butyric acid, ethanol, and butanol by anaerobic bioprocesses. In anaerobic fermentations of synthesis-gas, the rate-limiting step, which is a barrier to make commercial process, is gas-to-liquid mass transfer, due to extremely low solubility. In conventional stirred tank bioreactors, common approach used to enhance gas-to-liquid mass transfer rate is to make large interfacial area per unit gas volume by increasing the agitator’s power-to-volume ratio or using microbubble disperser. However, this approach is not economical for the large commercial-scale bioreactors, due to excessive power costs. In this study, bioprocess was developed to produce ethanol from CO, CO2 , and H2 by using Clostridium ljungdahlii (ATCC 55383). Scheme of biological reaction is as follows. 6CO + 3H2 O → CH3 CH2 OH + 4CO2 6H2 + 2CO2 → CH3 CH2 OH + 3H2 O The composition of gas substrate was 55% nitrogen, 20% carbon monoxide, 20% carbon dioxide, and 5% hydrogen, based on the composition of common synthesis gas. Anaerobic bioconversion reaction was successfully accomplished to produce ethanol in fermentor at a temperature of 37 ◦ C, and product composition was analyzed by using gas chromatography. Bundle of hollow fiber membranes were installed in bioreactor to supply gas substrate as shown in Fig. 1. Bubbles passed through membrane have microscale size, and slight positive pressure was applied to make long residence time due to attachment of bubbles on membrane surface. Using this operating method, gas substrate supply rate was controlled to same as substrate uptake rate. That resulted in the minimization of gas supply and the removal of recirculation of gas substrate in bioreactor. A proposed bioreaction process was successfully used to produce ethanol from synthesis gas.
Acknowledgement: This research was performed for the New & Renewable Energy R&D Program, funded by the Ministry of Knowledge Economy of Korea. doi:10.1016/j.jbiotec.2010.08.389 [P-B.37] Structural and biochemical approaches to design a synthetic agarolytic pathway: From agar to d-galactose and anhydro-lgalactose S. Lee 1,2,3 , K.H. Kim 1,2,3,∗ , I.-G. Choi 1,2,3 1
Korea University, Korea, Republic of University of California at Berkeley, United States 3 California Institute of Technology, United States Keywords: Agarolytic pathway; Neoagarobiose Agarases; Red algae 2
hydrolase;
Bioenergy production from marine biomass (e.g. macroalgae) has been recognized as an alternative route to overcome disadvantages of using land plant biomass. Among macroalgal biomass, red algae have been highlighted for the production of the sustainable biofuels and its major component is the agar polysaccharides. Many agarase families such as glycoside hydrolase (GH) 16, 50 and 86 families are involved in the microbial agarolytic system. With the synergistic action of these enzymes, agar is degraded into its end product (a disaccharide unt, neoagarobiose). This end product is assumed to be converted into two mono-sugars, d-galactose (GAL) and anhydro-l-galactose (AHG), which are metabolized by being integrated into the central metabolic pathway in agarolytic microbes. Although a few reports on the hydrolytic activity of neoagarobiose have been known, neither related gene nor its molecular information has been available yet. Here, we identified and cloned novel neoagarobiose hydrolase (NABH) enzymes from three kinds of agarolytic microorganisms. Among them, we determined atomic structure of NABH at 2.0 A˚ resolution from Saccharophagus degradans 2∼40 with or without GAL. We compared the atomic structure of agarases (e.g. GH 16) and NABH involved in agarolytic pathway. These atomic structures gave us clue to understand the enzymatic mechanism and evolution of these enzymes, which can provide a functional protein design principle. In addition, we designed an in vitro agarolytic system by obtaining several active agarases from the cloning of GH 16 and 50 family proteins. From the system, we tested a synthetic process for the deconstruction of agar biomass. We suggest that the synthetic process has potential for the efficient bioenergy production from red algal biomass by implementing a biomass deconstruction or consolidated bioprocess. doi:10.1016/j.jbiotec.2010.08.390