Microorganisms are able to drastically change the electrochemical conditions at the metal/solution interface by biofilm formation including bacterial consortia and extracellular polymeric substances (EPS) as the main components. The presence of biofilms generally facilitates the initiation of localized corrosion but this effect can be reversed to corrosion inhibition. Microbial corrosion inhibition and its counter process, microbiologically influenced corrosion (MIC) are rarely linked to a single mechanism or to a single species of microorganisms.

In recent years microbial inhibition of corrosion and protection of metals have been attributed to the blocking effect of biofilms and EPS. However, this simplistic approach must be discussed from an electrochemical point of view to understand the complex metal-microbe interactions at the metal surface. With this aim, several practical cases involving sulfate-reducing bacteria (SRB) and other microorganisms are critically discussed. General mechanisms for interpreting the influence of microorganisms on the protection and passivity of metals are presented.

Subject
Metal surfaces, Biofilms, Film formation, Metals, Bacteria, Corrosion inhibitors, Oxygen, Corrosion protection, Aluminum alloys, Cathodic inhibitors, Microorganisms, Passivity, Anodic inhibitors
Keywords:
Corrosion inhibition, Biofilms, Biocorrosion, Microbiologically influenced corrosion (MIC), Passivity, Metal protection, Extracellular polymeric substances (EPS)
© 2011 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2011
Association for Materials Protection and Performance (AMPP)
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