Iron corrosion by methane producing archaea (MPA) and sulfate reducing bacteria (SRB) utilizing metallic iron as an electron donor

Abstract

Methane Producing Archaea (MPA), which could utilize metallic iron as an electron donor and CO 2 as an electron acceptor and a carbon source, corroded an iron coupon severely in seawater medium under anaerobic condition (N 2 (80%) + CO 2 (20%)). Main component of corrosion products by MPA was FeCO 3. MPA corroded the iron coupon more severely when they coexisted with SRB which could also utilize metallic iron as an electron donor. Corrosion rate of the iron coupon by MPA + SRB was about 2.3 times higher than that by MPA only under anaerobic condition (N 2 (80%) + CO 2 (20%)). Main component of corrosion products by MPA + SRB was FeCO 3 like that by MPA. Corrosion rates of the iron coupon by MPA only, or MPA+ SRB under anaerobic condition (N 2(80%) + CO 2 (20%)) were higher than those under aerobic condition (Air) after the anaerobic corrosion experiments. Therefore, corrosive effects on iron by MPA+ SRB, which can utilize metallic iron as an electron donor, should be considered as cause of microbiologically influenced corrosion in the anaerobic corrosive environments like oil fields, where CO 2 and Cl - are available.