title: Microaeration enhances productivity of bioethanol from hydrolysate of waste house wood using ethanologenic Escherichia coli KO11.
abstract: This is the first study showing the successful application of waste house wood (WHW) to the pilot-scale production of bioethanol by hydrolysis using diluted acid and fermentation using the ethanologenic recombinant Escherichia coli KO11. The major sugars in the WHW hydrolysate were glucose, mannose and xylose; the percentages were approximately 35%, 35% and 20% (w/w), respectively. In anaerobic fermentation using a 5-l reactor in which the oxygen transfer rate (OTR) was 0 mmol/(l x h), KO11 consumed only 25% of the xylose in the WHW hydrolysate over the examined fermentation time of 100 h; however, hexoses such as glucose and mannose were consumed completely. Microaeration at an OTR of 4 mmol/(l x h) enhanced the xylose utilization ratio of KO11 to 100%, at which the ethanol concentration was 35.4 g/l and the ethanol yield was 0.42, although the maximum ethanol concentrations were 28.8 and 26.6 g/l at OTRs of 0 mmol/(l x h) and 15 mmol/(l x h), respectively. Moreover, this microaerobic fermentation at OTR of 4 mmol/(l x h) was applied to 1000-l scale bioethanol production using the WHW hydrolysate. The xylose utilization ratio reached 100% and the ethanol yield was determined to be 0.45 for a 63-h fermentation, which were comparable to those obtained from the laboratory-scale fermentation.
authors.affiliation: Bio Business Development Group, Tsukishima Kikai Co., Ltd., 17-15 Tsukuda 2-Chome, Chuo-ku, Tokyo 104-0051, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Okuda
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Ninomiya
authors.forename: Masako
authors.initials: M
authors.lastname: Takao
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Katakura
authors.forename: Suteaki
authors.initials: S
authors.lastname: Shioya
mesh_terms: D000332:Aerobiosis / Q000502:physiology; D000693:Anaerobiosis / Q000502:physiology; D004926:Escherichia coli / Q000254:growth & development* / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D006601:Hexoses / Q000737:chemistry / Q000378:metabolism*; D007218:Industrial Microbiology; D012037:Refuse Disposal; D014934:Wood / Q000737:chemistry* / Q000378:metabolism
chemical_list: D006601:Hexoses; D000431:Ethanol