Tributyltin (TBT) Tolerance of Indigenous and Non-indigenous Bacterial Species

Abstract

Tributyltin (TBT) is a species of organotin compound (OTC), used as antifouling biocide in boat and ship paints to prevents the attachment of marine organism on their hull surfaces. Tributyltin was found to be very toxic to a variety of targeted and non-targeted organisms and has high persistence in sediments even after the total global ban by the International Maritime Organization (IMO) in 2008. Therefore, there is an urgent need to clean up TBT-polluted environments after the global banning due to the significant risks it poses to the human and aquatic organisms for its slow degradation rate. In selecting bioremediation agents, indigenous bacteria were documented to be of great potentials compared to non-indigenous. In this study, comparison was made between a bacterial isolate Klebsiella sp. FIRD 2, isolated from TBT-contaminated surface sediment and Pseudomonas specie isolated from non-TBT-contaminated soil. Previously, we isolated, screened, and identified Klebsiella sp. FIRD 2 as a TBT-resistant bacterium from TBT-contaminated surface sediment of Kong Kong Laut, Johor, Malaysia. The isolate was able to resist TBT up to 1500 μg/L without addition of carbon source in minimal salt medium (MSM). Pseudomonas sp., isolated from non-TBT-contaminated soil was tested in MSM treated with different concentration of TBT. The bacterium did not endure to survive in TBT-treated media without addition of carbon source; thus, the strain has no ability to utilize TBT as source carbon. Growth of Pseudomonas sp. was observed in MSM treated with TBT at concentration of 500 μg/L and 1000 μg/L along with addition of glucose as carbon source. No growth of Pseudomonas sp. was observed in MSM with higher TBT concentration even with additional of carbon source. This study equally endorses the potentials of indigenous bacteria in bioremediation of TBT contamination.