Antifouling assessments on biogenic nanoparticles: A field study from polluted offshore platform

Turbinaria ornata mediated silver nanoparticles (TOAg-NPs) were evaluated for antibacterial activity against 15 biofilm forming bacterial isolates. A field study in natural seawater for 60 days showed antifouling activity of TOAg-NPs on stainless steel coupons (SS-304) coated with Apcomin zinc chrome (AZC) primer. Though TOAg-NPs showed broad spectrum of antibacterial activity, the maximum zone of inhibition was with Escherichia coli (71.9%) and a minimum with Micrococcus sp. (40%) due to the EPS secretion from Gram-positive bacteria. Compared to control coupons (18.9 [× 103], 67.0 [× 103], 13.5 [× 104] and 24.7 [× 104] CFU/cm2), experimental biocide coupons (71.0 [× 102], 32.0 [× 103], 82.0 [× 103] and 11.3 [× 104] CFU/cm2) displayed lesser bacterial population density. Toxicity studies revealed 100% mortality for Balanus amphitrite larvae at 250 μg ml− 1 concentration within 24 h, while 56.6% recorded for Artemia marina at the same concentration indicating less toxicity to non target species. It proved that AZC + TOAg-NPs prevent biofouling by its Ag-NS affinity and antimicrobial effectivity.