Search

The aim of this study was to investigate the influence of bovine serum albumin (BSA) on the Lactobacillus-strain-mediated removal of benzo[a]pyrene (BaP). A combination of 0.5 mg/mL of BSA with 1.0 × 1010 CFU/mL bacterial cells had a removal of 49.61% BaP for strain 121, while a combination of 0.4 mg/mL of BSA with 1.0 × 1010 CFU/mL bacterial cells had a removal of 66.09% BaP for strain ML32. The results indicated that the binding of BaP to Lactobacillus-BSA was stable. BSA maintains Lactobacillus activity and BaP removal in the gastrointestinal environment. Heat and ultrasonic treatment of BSA reduced the BaP-binding ability of Lactobacillus–BSA. With the addition of BSA, the surface properties of the two strains affected BaP binding. The Fourier-transform infrared (FTIR) data demonstrated that O-H, N-H, C=O, and P=O groups were involved in the binding of BaP to Lactobacillus–BSA. Scanning electron microscopy (SEM) results revealed that the morphology of Lactobacillus–BSA bound to BaP was maintained. The adsorption of BaP by Lactobacillus–BSA was appropriately described by the pseudo-second-order kinetic model and Freundlich isotherm model. BSA enhances the affinity between the bacterial cells and BaP.

The measured dynamic surface tension of a water drop in air saturated by heptane vapor shows a sharp decrease from about 60 mN m−1 to 40 mN m−1, and less after a certain adsorption time. The observed adsorption kinetics is analyzed by a theoretical model based on multilayer adsorption of alkanes from the vapor phase at the water surface. The model assumes a dependence of the kinetic coefficients of adsorption and desorption on the surface coverage and in equilibrium it reduces to the classical Brunauer–Emmett–Teller adsorption isotherm. The calculated time dependencies of adsorption and surface tension agree well with experimental data and predict a five-layer adsorption of heptane.