title: Evaluating Carriers for Immobilizing Saccharomyces cerevisiae for Ethanol Production in a Continuous Column Reactor.
abstract: We evaluated a more practical and cost-effective immobilization carriers for ethanol production using the yeast Saccharomyces cerevisiae. Three candidate materials-rice hull, rice straw, and sawdust-were tested for their cell-adsorption capacity and operational durability. Derivatizations of rice hull, rice straw, and sawdust with the optimal concentration of 0.5 M of 2-(diethylamino)ethyl chloride hydrochloride (DEAE · HCl) resulted in > 95% adsorption of the initial yeast cells at 2 hr for DEAE-rice hull and DEAE-sawdust and in only approximately 80% adsorption for DEAE-rice straw. In addition, DEAE-sawdust was found to be a more practical carrier for immobilizing yeast cells in terms of operational durability in shaking flask cultures with two different speeds of 60 and 150 rpm. Furthermore, the biosorption isotherms of DEAE-rice hull, -rice straw, and -sawdust for yeast cells revealed that the Qmax of DEAE-sawdust (82.6 mg/g) was greater than that of DEAE-rice hull and DEAE-rice straw. During the 404-hr of continuous column reactor operation using yeast cells immobilized on DEAE-sawdust, no serious detachment of the yeast cells from the DEAE-sawdust was recorded. Ethanol yield of approximately 3.04 g/L was produced steadily, and glucose was completely converted to ethanol at a yield of 0.375 g-ethanol/g-glucose (73.4% of the theoretical value). Thus, sawdust is a promising practical immobilization carrier for ethanol production, with significance in the production of bioethanol as a biofuel.
authors.affiliation: Department of Biotechnology, Korea National University of Transportation, Jeungpyung 368-701, Korea.
authors.forename: Hye-Geun
authors.initials: HG
authors.lastname: Cha
authors.affiliation: Department of Biotechnology, Korea National University of Transportation, Jeungpyung 368-701, Korea.
authors.forename: Yi-Ok
authors.initials: YO
authors.lastname: Kim
authors.affiliation: Department of Medical Biomaterials Engineering, Kangwon National University, Chuncheon 200-701, Korea.
authors.forename: Woon Yong
authors.initials: WY
authors.lastname: Choi
authors.affiliation: Korea Institute of Ocean Science and Technology, Ansan 426-744, Korea.
authors.forename: Do-Hyung
authors.initials: DH
authors.lastname: Kang
authors.affiliation: Department of Food Science and Engineering, Seowon University, Cheongju 361-742, Korea.
authors.forename: Hyeon-Yong
authors.initials: HY
authors.lastname: Lee
authors.affiliation: Department of Biotechnology, Korea National University of Transportation, Jeungpyung 368-701, Korea.
authors.forename: Kyung-Hwan
authors.initials: KH
authors.lastname: Jung
keywords: Continuous column reactor; Ethanol production; Immobilization carrier; Saccharomyces cerevisiae; Sawdust