Growth Kinetics Modelling of Tributytin-Resistant Klebsiella SP. FIRD 2 In Cadmium Media

Abstract

Tributyltin (TBT) has been generally used as a component of antifouling biocide in boat and ship paints to prevent the attachment of marine organisms on the hull surface. TBT has been classified to be a very toxic compound and poses significant danger to a broad diversity of organisms in polluted environments due to the high concentrations. The growth kinetics of a TBT-resistant bacterium containing cadmium was studied. In this study, various cadmium concentrations ranging from 1 to 100 mg/L were used. Seven kinetic models (Haldane, Teissier, Monod, Yano, Luong, Aiba, and Webb) were investigated, and the accuracy of the fitted models was evaluated using statistical analysis such as the coefficient of determination, adjusted coefficient of determination (R²), and root mean square error (RMSE). The Luong model was fitted to the experimental growth kinetics data and gave a very good fit. The calculated values for the Luong constants, such as maximal growth rate, half-saturation constant, and half-inhibition constant rate, symbolized by umax, ks, and ki, were 0.03405 hr⁻¹, 0.3 mg/L, and 0 mg/L, respectively. The Luong model also predicted the significant substrate concentration (Sm) value, at which the specific substrate degradation rate falls to zero (98.93 mg/L). This is the first report of the growth kinetics of a TBT-resistant bacterium by Klebsiella sp. FIRD 2 containing cadmium.