Abstract
Microbiologically influenced corrosion (MIC) is a major problem in the oil and gas industry as well as many other industries. Current treatment methods rely mostly on pigging and biocide dosing. Because field systems are not sterile, microbes always recover, leading to repeated treatment cycles. It is anticipated that the application of the same biocide will selectively promote resistant microbes. Overtime, this can lead to the biocide dosage escalating, resulting in a cost increase and environmental concerns. Previously published work demonstrated that some D-amino acids are biocide enhancers. D-amino acids are naturally occurring. They occupy a significant fraction of amino acids in processed food because of heat conversion of L-amino acids to D-amino acids. It has been postulated that D-amino acids can replace the D-alanine terminus in bacterial cell walls. Under a biocide stress, these D-amino acids can disperse recalcitrant biofilms such as the Desulfovibrio vulgaris biofilm on carbon steel coupons. It is well known that planktonic cells are much easier to treat than sessile cells. Because D-amino acids are used as signal molecules, only relatively low concentrations are needed. They can reduce biocide dosage while achieving increased efficacy. The new data provided herein reveal that a mixture of D-amino acids enhanced biocide treatment of two recalcitrant biofilm consortia, thus paving the way for field trials.
