Accession Number:

ADA411255

Title:

The Molecular Basis of Humic Acid Reduction and its Role in Microbiologically Influenced Corrosion

Descriptive Note:

Final rept. 1 Jan 2000-30 Aug 2002

Corporate Author:

CALIFORNIA INST OF TECH PASADENA

Personal Author(s):

Report Date:

2003-03-10

Pagination or Media Count:

4.0

Abstract:

Transposon mutagenesis was used to make mutants in Shewanella oneidensis strain MR-1. Two separate genetic screens were performed the first identified mutants that are defective in their ability to reduce AQDS a proxy for humic acid, the second identified mutants that are defective in their ability to make biofilms on steel chips. The mutants were subjected to a variety of tests to verify their phenotypes and further characterize their properties. The site of insertion of the transposon was determined. Select mutants defective in either humic acid reduction or biofilm formation were compared with respect to their ability to promote the corrosion of mild steel using electrochemical impedance spectroscopy. The principle results from this study were 1. the discovery that bacteria produce their own extracellular electron shuttles that can transfer electrons to iron minerals, and 2. that iron reduction can protect steel from corrosion.

Subject Categories:

  • Microbiology
  • Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE