摘要: |
The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. The technical approach for this quarter includes the application of new methods of Capsicum sp. (pepper) extraction by soxhlet method and analysis of a new set of extracts by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC); isolation and cultivation of MIC-causing microorganisms from corroded pipeline samples; and evaluation of antimicrobial activities of the old set of pepper extracts in comparison with major components of known biocides and corrosion inhibitors. Twelve new extracts from three varieties of Capsicum sp. (Serrano, Habanero, and Chile de Arbol) were obtained by soxhlet extraction using 4 different solvents. Results of TLC done on these extracts showed the presence of capsaicin and some phenolic compounds, while that of HPLC detected capsaicin and dihydrocapsaicin peaks. More tests will be done to determine specific components. Additional isolates from the group of heterotrophic, acid-producing, denitrifying and sulfate-reducing bacteria were obtained from the pipeline samples submitted by gas companies. Isolates of interest will be used in subsequent antimicrobial testing and test-loop simulation system experiments. Results of antimicrobial screening of Capsicum sp. extracts and components of known commercial biocides showed comparable activities when tested against two strains of sulfate-reducing bacteria. |