Daejeon, South Korea
Daejeon, South Korea

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Jang Y.-S.,KAIST | Malaviya A.,Synthetic Biotech Institute For The Biocentury | Lee J.,Synthetic Biotech Institute For The Biocentury | Im J.A.,Synthetic Biotech Institute For The Biocentury | And 5 more authors.
Biotechnology Progress | Year: 2013

Butanol is considered as a superior biofuel, which is conventionally produced by clostridial acetone-butanol-ethanol (ABE) fermentation. Among ABE, only butanol and ethanol can be used as fuel alternatives. Coproduction of acetone thus causes lower yield of fuel alcohols. Thus, this study aimed at developing an improved Clostridium acetobutylicum strain possessing enhanced fuel alcohol production capability. For this, we previously developed a hyper ABE producing BKM19 strain was further engineered to convert acetone into isopropanol. The BKM19 strain was transformed with the plasmid pIPA100 containing the sadh (primary/secondary alcohol dehydrogenase) and hydG (putative electron transfer protein) genes from the Clostridium beijerinckii NRRL B593 cloned under the control of the thiolase promoter. The resulting BKM19 (pIPA100) strain produced 27.9 g/l isopropanol-butanol-ethanol (IBE) as a fuel alcohols with negligible amount of acetone (0.4 g/l) from 97.8 g/l glucose in lab-scale (2 l) batch fermentation. Thus, this metabolically engineered strain was able to produce 99% of total solvent produced as fuel alcohols. The scalability and stability of BKM19 (pIPA100) were evaluated at 200 l pilot-scale fermentation, which showed that the fuel alcohol yield could be improved to 0.37 g/g as compared to 0.29 g/g obtained at lab-scale fermentation, while attaining a similar titer. To the best of our knowledge, this is the highest titer of IBE achieved and the first report on the large scale fermentation of C. acetobutylicum for IBE production. © 2013 American Institute of Chemical Engineers.

Jeon Y.-S.,KAIST | Jeon Y.-S.,Caltex R and nter | Yang J.-S.,Korea Institute of Science and Technology | Park E.-R.,Jeollabukdo | And 2 more authors.
Journal of the Taiwan Institute of Chemical Engineers | Year: 2016

In this study, we developed a new electrochemical process to remove the salts from food wastes. The primary removal mechanisms are washing and electromigration. The screw speed and current were selected as the primary factors influencing the removal of salts. An experimental design was applied in order to determine the optimum conditions for the removal of salts and 82.7% of the salts were removed under some of these conditions. Based on the continuous operation of the apparatus, the criteria for the removal of salts in the food composts could be achieved. © 2016 Taiwan Institute of Chemical Engineers.

Oh J.,Yonsei University | Yang S.,Yonsei University | Kim C.,Yonsei University | Choi I.,Caltex R and nter | And 2 more authors.
Applied Catalysis A: General | Year: 2013

Synthesis of biomass-derived lubricants via esterification, transesterification, and simultaneous reactions of both was studied by using sulfated zirconia catalysts. Soybean oil or free fatty acids derived from soybean oil were used as a biomass-derived resource for the synthesis of biolubricants. Long chain alcohols (carbon number ≥ 8) or neo-polyols (e.g., 2,2-diethyl-1,3-propanediol, trimethylol propane, pentaerythritol) were used as co-reactants. The structure of the alcohol significantly affected the conversion and yield for the esterification with oleic acid. The esters produced showed kinematic viscosity and viscosity index comparable to commercial lubricants. Various sulfated zirconia catalysts were prepared and were characterized by X-ray diffraction, NH3 temperature-programmed desorption, Brunauer-Emmett-Teller isotherm, and tested for esterification. The type of zirconium precursor demonstrated a significant effect on the physical property of the catalyst and its catalytic activity. Interestingly, esters with fully saturated hydrocarbon chains were synthesized from unsaturated free fatty acids regardless of the absence of hydrogen gas. The sulfated zirconia could be recycled for up to five repeated reactions without any degradation. The effects of reaction time and temperature were also investigated. © 2013 Elsevier B.V. All rights reserved.

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