Suppression of methanogenesis in hydrogen fermentation by intermittent feeding.
This study investigated whether intermittent feeding by using a concentrated carbon source is an appropriate method for selective enrichment of hydrogenesis by means of methanogen suppression. In a conventional reactor fed continuously for 10 d, methanogens increased from 2.8 × 10(7) to 1.1 × 10(9) gene copy number (GCN)/mg-cell dry weight, and methane concentration in the resulting biogas was 5.8%. However, when a carbon source was intermittently supplied for 10 d to the reactor, the number of methanogens was reduced 98.9% from 2.77 × 10(7) to 1.2 × 10(3) GCN/mg-cell dry weight, and methane was not detected during this period of intermittent feeding. Intermittent feeding shifted the dominants in the reactor from Clostridiaceae (70.5%) and Lactobacillaceae (11.0%) to Acetobacteraceae (62.0%) and Clostridiaceae (38.0%). In the reactor operated in continuous feeding mode after intermittent feeding, methane concentration was below 0.3% and the portion of methanogens in the bacterial community was maintained below 0.2%. These results suggest that the intermittent feeding of a carbon source during hydrogen production processes is a suitable method to suppress the activity of methanogens.
a Department of Environmental Science and Engineering , Ewha Womans University , Seoul , South Korea.
Jeonghee
J
Yun
a Department of Environmental Science and Engineering , Ewha Womans University , Seoul , South Korea.
Tae Gwan
TG
Kim
a Department of Environmental Science and Engineering , Ewha Womans University , Seoul , South Korea.
Kyung-Suk
KS
Cho
D016947:Acetobacteraceae / Q000378:metabolism; D056804:Biofuels / Q000032:analysis*; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D000068016:Eubacteriales / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification*; D019605:Euryarchaeota / Q000378:metabolism*; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005285:Fermentation; D018628:Gene Dosage; D006859:Hydrogen / Q000378:metabolism*; D007777:Lactobacillaceae / Q000378:metabolism; D008697:Methane / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000302:isolation & purification*
D056804:Biofuels; D003470:Culture Media; D004269:DNA, Bacterial; D005232:Fatty Acids, Volatile; D012336:RNA, Ribosomal, 16S; D002244:Carbon; D006859:Hydrogen; D008697:Methane
Biohydrogen; hydrogenesis; inhibition; intermittent feeding; methanogen