title: Repeated batch fermentation of immobilized E. coli expressing Vitreoscilla hemoglobin for long-term use.
abstract: This study describes an efficient and reusable process for ethanol production from medium containing whey powder, using alginate immobilized ethanologenic E. coli strains either expressing (TS3) or not expressing (FBR5) Vitreoscilla hemoglobin. Reuseabilities of the FBR5 and TS3 strains were investigated regarding their ethanol production capacities over the course of 15 successive 96-h batch fermentations. The ethanol production was fairly stable over the entire duration of the experiment, with strain TS3 maintaining a substantial advantage over strain FBR5. Storage of both strains in 2 different solutions for up to 60 d resulted in only a modest loss of ethanol production, with strain TS3 consistently outperforming strain FBR5 by a substantial amount. Strains stored for 15 or 30 d maintained their abilities to produce ethanol without dimunition over the course of 8 successive batch fermentations; again strain TS3 maintained a substantial advantage over strain FBR5 throughout the entire experiment. Thus, immobilization is a useful strategy to maintain the advantage in ethanol productivity afforded by expression of Vitreoscilla hemoglobin over long periods of time and large numbers of repeated batch fermentations, including, as in this case, using media with food processing wastes as the carbon source.
authors.affiliation: a Department of Molecular Biology and Genetics , Gebze Technical University , Gebze-Kocaeli , Turkey.
authors.forename: Taner
authors.initials: T
authors.lastname: Sar
authors.affiliation: a Department of Molecular Biology and Genetics , Gebze Technical University , Gebze-Kocaeli , Turkey.
authors.forename: Gamze
authors.initials: G
authors.lastname: Seker
authors.affiliation: a Department of Molecular Biology and Genetics , Gebze Technical University , Gebze-Kocaeli , Turkey.
authors.forename: Ayse Gokce
authors.initials: AG
authors.lastname: Erman
authors.affiliation: b Biology Department , Illinois Institute of Technology , Chicago , IL , USA.
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Stark
authors.affiliation: a Department of Molecular Biology and Genetics , Gebze Technical University , Gebze-Kocaeli , Turkey.|c Institute of Biotechnology, Gebze Technical University , Gebze-Kocaeli , Turkey.
authors.forename: Meltem
authors.initials: M
authors.lastname: Yesilcimen Akbas
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D061249:Batch Cell Culture Techniques / Q000379:methods*; D019149:Bioreactors / Q000382:microbiology; D049109:Cell Proliferation; D018914:Cells, Immobilized / Q000502:physiology*; D004926:Escherichia coli / Q000502:physiology*; D000431:Ethanol / Q000302:isolation & purification / Q000378:metabolism*; D024861:Genetic Enhancement / Q000379:methods*; D006454:Hemoglobins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D054793:Truncated Hemoglobins / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D006454:Hemoglobins; D011994:Recombinant Proteins; D054793:Truncated Hemoglobins; C082613:hemoglobin protein, Vitreoscilla; D000431:Ethanol
keywords: Vitreoscilla hemoglobin; ethanol; immobilization; repeated batch; whey