초록
<P><B>Abstract</B></P><P>Methane (CH<SUB>4</SUB>) can be mitigated through directly inhibiting methanogen activity and starving methanogens by hydrogen (H<SUB>2</SUB>) sink. Three types of mechanism (i.e. bromoethanesulphonate (BES), nitrate and emodin) and doses of CH<SUB>4</SUB> mitigation agents were employed to investigate their pathways of CH<SUB>4</SUB> inhibition. Results indicated that both BES and emodin inhibited CH<SUB>4</SUB> production and altered H<SUB>2</SUB> balance, which could be accompanied by decreased dry matter disappearance (DMD), fractional rate of gH<SUB>2</SUB> formation, volatile fatty acid (VFA) production, ability to produce and use reducing equivalences and molecular H<SUB>2</SUB>, and increased final asymptotic gH<SUB>2</SUB> production, time to the peak of gH<SUB>2</SUB>, discrete lag time of gH<SUB>2</SUB> production and fermentation efficiency. However, emodin decreased gas volume produced by rapidly fermentable components of substrate and the rate of fermentation at early stage of incubation, while BES supplementation inhibited gas volume produced by both rapidly and slowly fermentable components of substrate and the rate of fermentation at middle or late stage of incubation. The nitrate supplementation inhibited CH<SUB>4</SUB> production without affecting VFA profile, because of its dual role as H<SUB>2</SUB> sink and being toxic to methanogens. Nitrate supplementation had more complicated pattern of fermentation, VFA production and profile and H<SUB>2</SUB> balance in comparison to BES and emodin supplementation.</P>