Microbial interactions regulated by the dosage of ferroferric oxide in the co-metabolism of organic carbon and sulfate

Abstract

Effects of ferroferric oxide (Fe₃O₄) and organic carbon on co-metabolism of sulfate and organic carbon were investigated. With Fe₃O₄, the degradation of acetate and sulfate was inhibited when fed with acetate, while the degradation of acetate and propionate produced from ethanol was promoted when fed with ethanol. The dominant sulfate reducing bacteria (SRB) of acetate-fed reactors were Desulfobacteraceae (complete oxidizing SRB, CO-SRB) and Desulfurmonas (incomplete oxidizing SRB, IO-SRB). IO-SRBs of Desulfobulbus and Desulfomicrobium were dominant in ethanol-fed reactors. CO-SRB had higher competitiveness than methanogens to utilize acetate, while IO-SRBs might cooperate with methanogens to produce methane when dosed with ethanol and Fe₃O₄. The dosage of Fe₃O₄ changed the dominant methanogen from Methanosarcina to Methanosaeta with acetate as the organic carbon, while increased the relative abundance of Methanosaeta with ethanol as the organic carbon.

Keywords: Fe(3)O(4); Metagenomic analysis; Organic carbon metabolism; Sulfate reducing bacteria.