title: Tracing carbon monoxide uptake by Clostridium ljungdahlii during ethanol fermentation using (13)C-enrichment technique.
abstract: Conversion of synthesis gas (CO and H2) to ethanol can be an alternative, promising technology to produce biofuels from renewable biomass. To distinguish microbial utilization of carbon source between fructose and synthesis gas CO and to evaluate biological production of ethanol from CO, we adopted the (13)C-enrichment of the CO substrate and hypothesized that the residual increase in δ(13)C of the cell biomass would reflect the increased contribution of (13)C-enriched CO. Addition of synthesis gas to live culture medium for ethanol fermentation by Clostridum ljungdahlii increased the microbial growth and ethanol production. Despite the high (13)C-enrichment in CO (99 atom % (13)C), however, microbial δ(13)C increased relatively small compared to the microbial growth. The uptake efficiency of CO estimated using the isotope mass balance equation was also very low: 0.0014 % for the low CO and 0.0016 % for the high CO treatment. Furthermore, the fast production of ethanol in the early stage indicated that the presence of sugar in fermentation medium would limit the utilization of CO as a carbon source by C. ljungdahlii.
authors.affiliation: Department of Bio Environmental Chemistry and Institute of Life Science and Natural Resources, Wonkwang University, Iksan 570-749, Republic of Korea.
authors.forename: Seok-In
authors.initials: SI
authors.lastname: Yun
authors.forename: Seong-Joo
authors.initials: SJ
authors.lastname: Gang
authors.forename: Hee-Myong
authors.initials: HM
authors.lastname: Ro
authors.forename: Min-Jin
authors.initials: MJ
authors.lastname: Lee
authors.forename: Woo-Jung
authors.initials: WJ
authors.lastname: Choi
authors.forename: Seong-Gu
authors.initials: SG
authors.lastname: Hong
authors.forename: Kwon-Kyoo
authors.initials: KK
authors.lastname: Kang
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry / Q000378:metabolism; D002248:Carbon Monoxide / Q000378:metabolism*; D003013:Clostridium / Q000254:growth & development / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D000431:Ethanol; D002248:Carbon Monoxide