Time-of-Flight Secondary Ion Mass Spectrometry Analysis of Microbial Induced Corrosion of Glasses

Microbially-induced corrosion (MIC) is an emerging topic that has huge environmental impacts, such as long-term evaluation of microbial interactions with radioactive waste glass, environmental cleanup and disposal of radioactive material, and weathering effects of microbes. Improved understanding of relevant bacterial systems and biological secretions help in the development of nuclear waste vitrification materials. A Paenibacillus sp. originating near the Hanford site subsurface was investigated as a model biofilm system. Time-of-flight secondary ion mass spectrometry (ToF–SIMS) – a powerful mass spectral imaging technique with high surface sensitivity, mass resolution, and mass accuracy – is used to study biofilm effects on different substrates. The first study examined the stress response of a biofilm to low carbon source media and suggested that it is a suitable choice to study biomineralization and microbial effects on materials corrosion. Next desalination protocols for thin biofilms adhered to glass surfaces were examined, as desalination is required prior to ToF-SIMS analysis. Comparisons of two desalinating methods, centrifugal spinning (CS) and water submersion (WS), show a decrease of the media peaks up to 99% using CS and 55% using WS, respectively. Next, two types of glass, Granite and Dike, were investigated for MIC of Paenibacillus polymyxa SCE2 biofilms after seven month inoculation. Multimodal imaging and ToF-SIMS were used to verify bacterial coverage, surface and interface compositional and spatial differences, and identify microbial induced corrosion products across the glass surface after long term growth. Finally, a utilization of femtosecond laser ablation in combination with ToF-SIMS is presented for removal of biofilm layers to uncover aerobic and anaerobic differences in a Paenibacillus bacterial biofilm.