ABSTRACT
Strains used in the experiment were enrichment cultured, separated and purified from Yingtan actual soil. SRB was cultured according to the standards recommended by the American Petroleum Institute (API) in medium.[9] The medium components were as follows: 0.5 g Na2SO4, 1.0 g NH4Cl, 0.1 g CaCl2, 0.5 g K2HPO4 ⋅ 3H2O, 2.0 g MgSO4 ⋅ 7H2O, sodium lactate 3.5 g and 1.0 g yeast extract powder. The medium was made with 1 L of soil simulation solution. A 0.1 g ascorbic acid, 0.1 g ammonium ferrous sulfate and 0.1 g sodium hydrosulfite were added to the medium which was
1 INTRODUCTION
Despite the developments in buried pipeline technology, problem of metal corrosion and protection in the soil has attracted people’s attention. Corrosion of buried pipeline is the result of joint action of numerous factors, and the MIC is particularly serious. According to statistics, global loss caused by MIC is up to 10 billion dollars a year.[1] SRB are a kind of typical anaerobic bacteria which depends on organic matter for nourishment,[2] widely exist in the soil, sea mud, water, oil and gas wells and underground pipes; they are all anoxic environments. SRB is one of the main corrosive bacteria which cause the pipeline steel corrosion in the anaerobic environment,[3,4] and can even lead to serious corrosion of all common metallic materials.[5-7]
At present, many scholars are working on a lot of SRB all around the world, and have put forward different views. Most of the research concentrated on the discussion of SRB corrosion in the marine environment. In recent years, research of corrosion caused by SRB in the soil environment has been also growing. However, there are numerous different kinds of soil in our country. The content of SRB in different places and different kinds of soil is quite different. And the corrosion mechanism
irradiated for 30 minutes by ultraviolet. All reagents were of analytical grade purity. The medium was sterilized for 20 minutes under high pressure at 121°C. After cooling, SRB strains were inoculated. Then they were incubated in biochemical incubator after sealing for 3-5 day at 30±1°C. When the bacteria solution was black with rotten egg smell, it was stored at 4°C in the refrigerator. In order to ensure the content of bacterial for consistency, all experimental bacterial solutions were inoculated and cultured for 4 days. The frozen bacteria would be used after constant temperature activation. The above operations were required vaccination carried out in a sterile workbench.
