title: Changes in bacterial community during fermentative hydrogen and acid production from organic waste by thermophilic anaerobic microflora.
abstract: OBJECTIVE
  Changes in fermentation pattern during the treatment of organic wastes containing solid materials by thermophilic anaerobic microflora were investigated with respect to product formation and bacterial community structure during hydrogen production.
  
  
  RESULTS
  Anaerobic microflora enriched from sludge compost was cultivated using artificial garbage slurry in a continuous flow-stirred tank reactor. Product formation varied depending on pH and hydraulic retention time (HRT) applied. Community analysis by terminal restriction fragment length polymorphism and clone library analysis of polymerase chain reaction-amplified bacterial 16S rDNA indicated that difference in the fermentative product distribution could be caused by different populations of micro-organisms in the microflora.
  
  
  CONCLUSIONS
  Hydrogen fermentation with acetate/butyrate formation was optimized at <1.0 d HRT at pH 5.0 and 6.0. Thermoanaerobacterium thermosaccharolyticum was the dominant hydrogen-producing micro-organism. Conversely, unidentified organisms became dominant after 4.0 d HRT at pH 7.0 and 8.0, where relatively high-solubilization efficiency of solid materials was observed with no production of hydrogen.
  
  
  CONCLUSIONS
  This is the first report describing product formation in the fermentation of solid organic wastes by a mixed population of micro-organisms. Various fermentation patterns including hydrogen fermentation were characterized and evaluated from engineering and microbial aspects.
authors.affiliation: Kajima Technical Research Institute, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ueno
authors.forename: D
authors.initials: D
authors.lastname: Sasaki
authors.forename: H
authors.initials: H
authors.lastname: Fukui
authors.forename: S
authors.initials: S
authors.lastname: Haruta
authors.forename: M
authors.initials: M
authors.lastname: Ishii
authors.forename: Y
authors.initials: Y
authors.lastname: Igarashi
mesh_terms: D000143:Acids; D001419:Bacteria / Q000378:metabolism*; D001483:Base Sequence; D018533:Biomass; D019149:Bioreactors; D004269:DNA, Bacterial / Q000032:analysis; D004736:Energy-Generating Resources; D005285:Fermentation; D015723:Gene Library; D006859:Hydrogen; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D012150:Polymorphism, Restriction Fragment Length; D025341:Principal Component Analysis; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D012722:Sewage; D046950:Thermoanaerobacterium / Q000378:metabolism; D013997:Time Factors; D014865:Waste Disposal, Fluid
chemical_list: D000143:Acids; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D006859:Hydrogen