title: Preparation of corncob grits as a carrier for immobilizing yeast cells for ethanol production.
abstract: In this study, DEAE-corncobs [delignified corncob grits derivatized with 2-(diethylamino)ethyl chloride hydrochloride (DEAE·HCl)] were prepared as a carrier to immobilize yeast (Saccharomyces cerevisiae) for ethanol production. The immobilized yeast cell reactor produced ethanol under optimized DEAE·HCl derivatization and adsorption conditions between yeast cells and the DEAE-corncobs. When delignified corncob grit (3.0 g) was derivatized with 0.5M DEAE·HCl, the yeast cell suspension (OD600 = 3.0) was adsorbed at >90% of the initial cell OD600. This amount of adsorbed yeast cells was estimated to be 5.36 mg-dry cells/g-DEAE corncobs. The Qmax (the maximum cell adsorption by the carrier) of the DEAE-corncobs was estimated to be 25.1 (mg/g), based on a Languir model biosorption isotherm experiment. When we conducted a batch culture with medium recycling using the immobilized yeast cells, the yeast cells on DEAE-corncobs produced ethanol gradually, according to glucose consumption, without cells detaching from the DEAE-corncobs. We observed under electron microscopy that the yeast cells grew on the surface and in the holes of the DEAEcorncobs. In a future study, DEAE-corncobs and the immobilized yeast cell reactor system will contribute to bioethanol production from biomass hydrolysates.
authors.affiliation: Department of Biotechnology, Chungju National University, Jeungpyung, Chungbuk, Korea.
authors.forename: Sang-Eun
authors.initials: SE
authors.lastname: Lee
authors.forename: Choon Geun
authors.initials: CG
authors.lastname: Lee
authors.forename: Do Hyung
authors.initials: DH
authors.lastname: Kang
authors.forename: Hyeon-Yong
authors.initials: HY
authors.lastname: Lee
authors.forename: Kyung-Hwan
authors.initials: KH
authors.lastname: Jung
mesh_terms: D000327:Adsorption; D056804:Biofuels; D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000295:instrumentation / Q000379:methods; D018914:Cells, Immobilized / Q000166:cytology* / Q000378:metabolism*; D000431:Ethanol / Q000032:analysis / Q000378:metabolism*; D004983:Ethanolamines / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism*; D003313:Zea mays / Q000737:chemistry*
chemical_list: D056804:Biofuels; D004983:Ethanolamines; D000431:Ethanol; C007369:2-diethylaminoethanol