Novel peptides based on sea squirt as biocide enhancers to mitigate biocorrosion of EH36 steel.

Microbiologically influenced corrosion (MIC) affects offshore production activities severely. Although adding biocides is a simple method, it can cause environmental damage over time. Using green biocide enhancers is a viable strategy to reduce the amount of biocides. In this study, four novel peptides, named Peptide T/Tc/Ts/Tcs, were designed by a natural peptide extracted from the Arctic sea squirt to enhance the efficacy of tetrakis hydroxymethyl phosphonium sulfate (THPS) in mitigating the biocorrosion of EH36 steel caused by Desulfovibrio ferrophilus. The combination of 40 ppm THPS and 100 nM Peptide T/Tc/Ts/Tcs reduced the corrosion rates of EH36 steel by 68 %, 71 %, 86 %, and 90 % after the 7-d incubation, respectively. Notably, 40 ppm THPS + 100 nM Peptide Ts/Tcs achieved similar antimicrobial and biocorrosion mitigation effects as 100 ppm THPS. It suggests that optimizing the cationic and hydrophobic properties of peptides could enhance the bactericidal properties of biocides.