Changes in dominant fermentation type during anaerobic digestion of high-loading glycerol with slight glucose content.
High-loading glycerol containing slight amounts of five different monosaccharides was inoculated with seed sludge obtained from a methane fermentation reactor. The use of different monosaccharides as fermentation promoters resulted in changes in fermentation types; in particular, glucose induced the formation of 1,3-propanediol. After 9 days incubation with glucose, glycerol levels had fallen by 81%, while molar yields of organic acids and 1,3-propanediol (per mole of glycerol degraded) were 0.22 and 0.39, respectively. Other monosaccharides enhanced methane production after 14 days of incubation in the following order: galactose, galacturonic acid, mannose and arabinose. Hydrogen was generated (together with a negligible amount of methane) only in the presence of glucose. When glucose was introduced to a methane-producing reactor (promoted by galacturonic acid), hydrogen production began 5 days later and displaced the methane production after 12 days. These results suggest that glucose catalyzes glycerol degradation, resulting in the production of hydrogen.
Department of Chemical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan. tokumoto@chemeng.osakafu-u.ac.jp
Hayato
H
Tokumoto
Mai
M
Kashiwagi
D000693:Anaerobiosis / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D056804:Biofuels / Q000032:analysis; D005285:Fermentation / Q000187:drug effects; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D005990:Glycerol / Q000378:metabolism* / Q000494:pharmacology; D006603:Hexuronic Acids / Q000494:pharmacology; D008697:Methane / Q000032:analysis; D012722:Sewage / Q000382:microbiology
D056804:Biofuels; D006603:Hexuronic Acids; D012722:Sewage; C007819:galacturonic acid; D005947:Glucose; D008697:Methane; D005990:Glycerol