Evaluation of biological and enzymatic quorum quencher coating additives to reduce biocorrosion of steel

Abstract

Microbial colonization can be detrimental to the integrity of metal surfaces and lead to microbiologically influenced corrosion (MIC). Biocorrosion is a serious problem for aquatic and marine industries in the world. In Minnesota (USA), where this study was conducted, biocorrosion severely affects the maritime transportation industry. The anticorrosion activity of a variety of compounds, including chemical (magnesium peroxide) and biological (surfactin, capsaicin, and gramicidin) molecules were investigated as coating additives. We also evaluated a previously engineered, extremely stable, non-biocidal enzyme known to interfere in bacterial signaling, Sso Pox (a quorum quenching lactonase). Experimental steel coupons were submerged in water from the Duluth Superior Harbor (DSH) for 8 weeks in the laboratory. Biocorrosion was evaluated by counting the number and the coverage of corrosion tubercles on coupons and also by ESEM imaging of the coupon surface. Three experimental coating additives significantly reduced the formation of corrosion tubercles: surfactin, magnesium peroxide and the quorum quenching lactonase by 31%, 36% and 50%, respectively. DNA sequence analysis of the V4 region of the bacterial 16S rRNA gene revealed that these decreases in corrosion were associated with significant changes in the composition of bacterial communities on the steel surfaces. These results demonstrate the potential of highly stable quorum quenching lactonases to provide a reliable, cost-effective method to treat steel structures and prevent biocorrosion.

Use of Quorum Sensing Inhibition Strategies to Control Microfouling

“…Also, little is known about the effect of the interference of QS systems on the microbial composition of multispecies biofilms. The use of the QQ enzyme SsoPox as a coating additive was recently reported to significantly decrease biocorrosion in steel coupons after 8 weeks of submersion in water, and this effect was associated with a deep change in the microfouling community [ 28 ]. In the present work, adding the AHL-lactonase Aii20J (0.57 mM) clearly inhibited the mixed biofilms containing the QQ-sensitive P. flavipulchra strain.…”

“…In this sense, the AHL-lactonase Aii20J has been reported to be active against AHL producers [ 12 , 22 , 23 ], but also against bacterial strains that are not [ 21 ]. Moreover, previous studies indicated that the external addition of QQ enzymes that degrade AHLs into complex biofilm could affect both Gram-negative and Gram-positive bacteria [ 14 , 28 , 29 , 30 ].…”

“…Also, many bacteria have developed QQ enzymes that degrade QS signals [ 21 , 22 , 23 , 24 ], and this is the most-studied QS interference strategy. Using QQ enzymes that can degrade the AHLs produced by Gram-negative bacteria has been suggested as a novel anti-biofouling strategy [ 25 , 26 , 27 ], and a few studies have evaluated the effect of QQ enzymes on the ecology of multispecies biofilms [ 14 , 28 , 29 , 30 ]. QQ strategies have been successfully applied to control biofouling in membrane bioreactors (MBRs) for wastewater treatment [ 11 , 15 ] and to reduce biocorrosion [ 28 ], as they are associated with deep changes in the microfouling community [ 28 ].…”

“…Using QQ enzymes that can degrade the AHLs produced by Gram-negative bacteria has been suggested as a novel anti-biofouling strategy [25][26][27], and a few studies have evaluated the effect of QQ enzymes on the ecology of multispecies biofilms [14,[28][29][30]. QQ strategies have been successfully applied to control biofouling in membrane bioreactors (MBRs) for wastewater treatment [11,15] and to reduce biocorrosion [28], as they are associated with deep changes in the microfouling community [28]. This effect could be observed even in in vitro oral biofilm models dominated by Gram-positive species [14].…”

Engineering acyl-homoserine lactone-interfering enzymes toward bacterial control

“…The presence of SsoPox variant in capsules led to changes in bacterial communities and to biofilm inhibition (102). SsoPox W263I immobilized in a silica gel coating painted on steel plates was also able to reduce corrosion tubercles by 50% compared with controls after 8 weeks of immersion in Duluth-Superior Harbor (Minnesota, USA) (103). The use of enzymes instead of or as a complementation to biocides in paint is attractive, due to use restriction of some biocides because of their negative impact on the environment (125).…”