Rapid anaerobic degradation of carbon steel exposed to Desulfoglaeba alkanexedens media

摘要

This work is a collaborative effort involving multidisciplinary and multi-institutional scientific groups with a common objective of determining "to what extent the biocorrosion of carbon steel experienced in marine systems can be correlated with anaerobic fuel biodegradation." Within this context our group's specific tasks include but are not limited to understanding the elementary steps of microbially influenced corrosion on carbon steel: This involves developing a versatile experimental platform employing a wide range of surface imaging and surface analytical techniques that address the fundamental mechanisms of the anaerobic carbon steel biodeterioration process resulting from the anaerobic biodegradation of fuel in marine systems in the presence of sulfate, at the nano-, micro- and macroscales. Here we present preliminary data revealing a very rapid degradation of carbon steel surface upon exposure to a culture of fuel-degrading Desulfoglaeba alkanexedens (strain ALDCT) under anaerobic conditions. We also present data on control experiments conducted using Na2S solutions and compare their effect on the initial degradation of carbon steel surface under high and normal pH conditions and under highly controlled anaerobic conditions. All evidence points to pH playing a key role in the anaerobic corrosion of C steel in the presence of sulfide ions in the solution. Furthermore, the precipitation of the corrosion minerals forms open morphologies with submicron-sized channels, connecting the solution phase to the clean Fe surface and thus enabling sustainable corrosion. The results suggest that the abiotic and biotic general corrosion processes are driven by the same chemical reactions: Fe + 2 H~+ = Fe~(2+) + H_2↑ and Fe~(2+) S~(2-) = FeS↓, though SRB-mediated MIC may proceed at a very different rate than the abiotic process, which is yet to be quantified.