Phosphate Inhibits Acetotrophic Methanogenesis on Rice Roots

Abstract

ABSTRACT The contribution of acetate- and H 2 /CO 2 -dependent methanogenesis to total CH 4 production was determined in excised washed rice roots by radiolabeling, methyl fluoride inhibition, and stable carbon isotope fractionation. Addition of ≥20 mM phosphate inhibited methanogenesis, which then was exclusively from H 2 /CO 2 . Otherwise, acetate contributed about 50 to 60% of the total methanogenesis, demonstrating that phosphate specifically inhibited acetotrophic methanogens on rice roots.