Evaluation of essential oil from Zataria multiflora as natural antibiofouling agents in epoxy paint for marine application

Regarding the negative impacts of using toxic antifouling paints to solve the problem of biofouling, the development of non-toxic paints from natural products and their application in marine industries has gain importance. In the present study, the antifouling properties of Zataria multiflora essential oil in antifouling epoxy paint were investigated. Antibiofouling activity of essential oil was proved by antibacterial, antimicroalgal, antibarnacel and antiartemia activities. The minimum inhibitory concentration was 0.125 and 0.250 mg/L against two bacteria Staphylococcus aureus and Escherichia coli, respectively. According to antimicroalgal adherence assay, essential oil had inhibited the average specific growth rate of Isochrysis galbana with effective concentration of 52.186±17.67mg/L and LC50 was 8.720±1.28 and 35.210±2.37mg/L against antibarnacel and antiartemia, respectively. The essential oil was added to epoxy paint and coated on the fiberglass panel exposed to seawater for three months. At the end of the first and second months, the coated panels containing 3% essential oil had the lowest weight (78.81±22.2 and 178.44±6.58 g, respectively) and lowest fouling cover percentage (63.52±1.92% and 92.05±3.34%, respectively) (P<0.05). Results showed that the effectiveness of antifouling activity of Z. multiflora essential oil depends on the amount of essential oil in the paint and its wash rate in seawater.