Sulfide enhances methanogenesis in nitrate-containing methanogenic cultures
Journal
Bioresource Technology
Journal Volume
102
Journal Issue
3
Pages
2427-2432
Date Issued
2011
Author(s)
Wong B.-T.
Abstract
The effects of sulfide on nitrate reduction and methanogenesis using butyrate as a carbon source were investigated in a mixed mesophilic, methanogenic culture. In the sulfide-free medium, 25-75mgl-1 nitrate markedly inhibited the efficiencies of acetogenesis and methanogenesis processes. Adding 25mg-Sl-1 increased methane production in nitrate-amended medium. Low sulfide levels shifted the nitrate reduction pathway from denitrification to dissimilatory nitrate reduction to ammonia (DNRA), thereby reducing the amounts of toxic nitric oxide and nitrous oxide produced that inhibit methanogenesis. The dose of 25mgl-1 sulfide was oxidized completely, during which heterotrophic DNRA predominated. The oxidized forms of sulfide reformed, limiting induction of the heterotrophic denitrification pathway. The actions of heterotrophic and autotrophic DNRA bacteria, denitrifiers, sulfate-reducing bacteria and methanogens mitigate nitrate toxicity during methanogenesis in an anaerobic process. ? 2010 Elsevier Ltd.
Subjects
DNRA
Methanogenesis
Nitrate reduction
Sulfide
Type
journal article