Effect of yeast extract on microbiologically influenced corrosion of X70 pipeline steel by SRB

Abstract Microbiologically influenced corrosion (MIC) is a complex process involving interactions between microorganisms, materials and surrounding environment. Yeast extract (YE) is a routinely added nutritional ingredient in many kinds of microbial culture media. However, the effect of YE on MIC was not clear. In this work, the corrosion behaviors of X70 pipeline steel in the sulfate reducing bacterial (SRB) Desulfovibrio bizertensis SY-1 inoculated media with or without YE were studied. The results showed that the weight loss of coupons in sterile media increased twofold after removing YE from culture media (P = 0.04). While in the SRB culture medium, removing YE decreased the planktonic bacteria number, but significantly promoted the attachment of bacteria on steel surfaces. Besides, the corrosion rate of steel in SRB media without YE was four times higher than with YE (P = 0.003). MIC was not determined by the planktonic SRB cells but the attached biofilm. The results identified effect of YE on D. bizertensis SY-1 growth and confirmed the inhibition role of YE in MIC induced by SRB.