{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/12327"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/12327","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes","abstract":"The mechanism of the corrosive action of sulphate reducing bacteria of the genus Desulfovibrio towards ferrous metals has been investigated. This corrosive action is anomalous when considered in the light of established knowledge of corrosion processes, since it occurs in the absence of oxygen, at more or less neutral pH values and at ordinary ambient temperatures. The hypothesis of von Wolzogen Kuhr and van der Vlugt, published in 1934, proposing that enzymic catalysis of sulphate reduction by cathodic charge constituted a \"cathodic depolarizing\" process, which appears t o be widely accepted as the most likely mechanism for this corrosive effect, is evaluated critically here in the light of established electrochemical and biochemical knowledge. The theoret ical arguments presented in this thesis show that this process, if it does occur, is unlikely to affect corrosion rates. The experimental results presented here indicate that all cathodic depolarizing activity demonstrated in pure cultures of these organisms is attributable to the cathodic activity of dissolved hydrogen sulphide produced by the organisms. The conclusions of other workers, quoted in support of proposed enzymic catalysis of charge transfer from cathodes to redox dyes in laboratory systems, are considered, in view of experimental work performed during this investigation, to be a misinterpretation of experimental results.","abstract_html":"The mechanism of the corrosive action of sulphate reducing bacteria of the genus Desulfovibrio towards ferrous metals has been investigated. This corrosive action is anomalous when considered in the light of established knowledge of corrosion processes, since it occurs in the absence of oxygen, at more or less neutral pH values and at ordinary ambient temperatures. The hypothesis of von Wolzogen Kuhr and van der Vlugt, published in 1934, proposing that enzymic catalysis of sulphate reduction by cathodic charge constituted a "cathodic depolarizing" process, which appears t o be widely accepted as the most likely mechanism for this corrosive effect, is evaluated critically here in the light of established electrochemical and biochemical knowledge. The theoret ical arguments presented in this thesis show that this process, if it does occur, is unlikely to affect corrosion rates. The experimental results presented here indicate that all cathodic depolarizing activity demonstrated in pure cultures of these organisms is attributable to the cathodic activity of dissolved hydrogen sulphide produced by the organisms. The conclusions of other workers, quoted in support of proposed enzymic catalysis of charge transfer from cathodes to redox dyes in laboratory systems, are considered, in view of experimental work performed during this investigation, to be a misinterpretation of experimental results.","abstract_has_math":false,"creators":["Costello, John Anthony"],"institution":"Department of Chemistry","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Liesegang, E C"],"committee_chairs":[],"committee_members":[],"year":1975,"date_issued":"1975","date_published":"1975","updated_at":"2026-07-22T22:22:42Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/12327","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Liesegang, E C"]},{"key":"dc:creator","label":"Author","values":["Costello, John Anthony"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-01-27T10:05:04Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-01-27T10:05:04Z"]},{"key":"dc:date.issued","label":"Date","values":["1975"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Chemistry"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Doctoral Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["PhD"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/12327"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Includes bibliographical references."]},{"key":"dc:description.abstract","label":"Abstract","values":["The mechanism of the corrosive action of sulphate reducing bacteria of the genus Desulfovibrio towards ferrous metals has been investigated. This corrosive action is anomalous when considered in the light of established knowledge of corrosion processes, since it occurs in the absence of oxygen, at more or less neutral pH values and at ordinary ambient temperatures. The hypothesis of von Wolzogen Kuhr and van der Vlugt, published in 1934, proposing that enzymic catalysis of sulphate reduction by cathodic charge constituted a \"cathodic depolarizing\" process, which appears t o be widely accepted as the most likely mechanism for this corrosive effect, is evaluated critically here in the light of established electrochemical and biochemical knowledge. The theoret ical arguments presented in this thesis show that this process, if it does occur, is unlikely to affect corrosion rates. The experimental results presented here indicate that all cathodic depolarizing activity demonstrated in pure cultures of these organisms is attributable to the cathodic activity of dissolved hydrogen sulphide produced by the organisms. The conclusions of other workers, quoted in support of proposed enzymic catalysis of charge transfer from cathodes to redox dyes in laboratory systems, are considered, in view of experimental work performed during this investigation, to be a misinterpretation of experimental results."]},{"key":"dc:title","label":"Title","values":["The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes"]}]}],"canonical_facts":{"dc:contributor.advisor":["Liesegang, E C"],"dc:creator":["Costello, John Anthony"],"dc:date.accessioned":["2015-01-27T10:05:04Z"],"dc:date.available":["2015-01-27T10:05:04Z"],"dc:date.issued":["1975"],"dc:description":["Includes bibliographical references."],"dc:description.abstract":["The mechanism of the corrosive action of sulphate reducing bacteria of the genus Desulfovibrio towards ferrous metals has been investigated. This corrosive action is anomalous when considered in the light of established knowledge of corrosion processes, since it occurs in the absence of oxygen, at more or less neutral pH values and at ordinary ambient temperatures. The hypothesis of von Wolzogen Kuhr and van der Vlugt, published in 1934, proposing that enzymic catalysis of sulphate reduction by cathodic charge constituted a \"cathodic depolarizing\" process, which appears t o be widely accepted as the most likely mechanism for this corrosive effect, is evaluated critically here in the light of established electrochemical and biochemical knowledge. The theoret ical arguments presented in this thesis show that this process, if it does occur, is unlikely to affect corrosion rates. The experimental results presented here indicate that all cathodic depolarizing activity demonstrated in pure cultures of these organisms is attributable to the cathodic activity of dissolved hydrogen sulphide produced by the organisms. The conclusions of other workers, quoted in support of proposed enzymic catalysis of charge transfer from cathodes to redox dyes in laboratory systems, are considered, in view of experimental work performed during this investigation, to be a misinterpretation of experimental results."],"dc:identifier.uri":["http://hdl.handle.net/11427/12327"],"dc:language.iso":["eng"],"dc:publisher.department":["Department of Chemistry"],"dc:publisher.institution":["University of Cape Town"],"dc:title":["The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes"],"dc:type":["Doctoral Thesis"],"dc:type.qualificationlevel":["Doctoral"],"dc:type.qualificationname":["PhD"]},"updated_at":"2026-07-22T22:22:42Z"}