A sea anemone-inspired small synthetic peptide at sub-ppm concentrations enhanced biofilm mitigation

A biocide enhancer is a chemical that can enhance the efficacy of a biocide or reduce its dosage. In this work, a novel peptide was tested as a biocide enhancer. A chemically synthesized 14-mer peptide (Peptide A), which was found non-biocidal, has an amino acid sequence derived from sea anemone Actinia equina that possesses a biofilm-free exterior. Peptide A at 180 ppb (w/w) or 100 nM enhanced 100 ppm tetrakis hydroxymethyl phosphonium sulfate (THPS) against an oilfield biofilm consortium grown on C1018 carbon steel in an enriched artificial seawater medium. The combination of 100 nM Peptide A + 100 ppm THPS led to additional 2-log reduction, 1-log reduction, 1-log reduction in sessile sulfate reducing bacteria (SRB) cell count, sessile acid producing bacteria (APB) cell count, and sessile general heterotrophic bacteria (GHB) cell count, in comparison with the treatment using 100 ppm THPS alone in a 14-day laboratory biofilm prevention test. The data in this work suggest that non-biocidal Peptide A is a promising biocide enhancer that should be further explored. [Display omitted] •Cyclic Peptide A is engineered based on a 12-mer sequence in Equinatoxin II protein.•Peptide A reduces tetrakis (hydroxymethyl) phosphonium sulfate (THPS) dosage.•Peptide A at ppb levels enhances the biocide against an oilfield biofilm consortium.•The biocide cocktail reduces carbon steel weight loss and maximum pit depth.•Linear polarization resistance results corroborate weight loss and pitting data.