The effect of Pseudomonas fluorescens on buried steel pipeline corrosion: Supporting Information

摘要: Agar electrolyte preparation A mixture containing 4.0 g/L of agar, 12.5 g/L of Oxoid Nutrient Broth No. 2 (10.0 g/L Lab Lemco powder, 10.0 g/L peptone and 5.0 g/L sodium chloride) and 2.5 g/L of sodium chloride was made with distilled water and heated via microwave until fully dissolved. Once the components were dissolved, the solution was adjusted with 0.1 M sodium hydroxide to a pH of 7.0±0.1. The solution was then autoclaved at 121 C for 15 minutes. The agar was de-aerated by bubbling nitrogen gas through the solution and cooled gradually to below 60 C before the dissolved oxygen (DO) levels were measured with a portable meter and probe. Once a DO level of≤ 0.1 mg/L was reached, compressed air was bubbled through the solution to bring the DO to maximum (approximately 5.0 mg/L). All samples were set with air bubbling into the flat cell to ensure the maximum oxygen levels were maintained.Bacterial culture Gram negative P. fluorescens, strain ATCC49642, was cultured on media made from 25.0 g/L Nutrient Broth No. 2 with 12.0 g/L of agar added. The media was sterilized at 121 C for 15 minutes before being poured into plates under sterile conditions. P. fluorescens was streaked onto the surface of the media once set and incubated at 30 C for 36-48 hours. Following incubation the plates were stored at 4 C until required.