EFFECT OF TIME AND INCUBATION TEMPERATURE ON ABILITY OF PROBIOTICS FOR REMOVAL OF POLYCYCLIC AROMATIC HYDROCARBON IN PHOSPHATE BUFFER SALINE

Abstract

The ability of Lactobacillus acidophilus LA-5, Bifidobacterium lactis BB-12, Lactobacillus delbrueckii subsp. bulgaricus PTCC 1737 and Streptococcus thermophilus PTCC 1738 in removing Benzo(a)pyrene (BaP), Benz(a)anthracene (BaA), Chrysene (Chr) and Benzo(b)fluoranthene (BbF) from contaminated aqueous solution with respect to strain types, time and temperature of incubation was studied. The results showed that BaA, Chr, BbF and BaP could be significantly removed from the phosphate buffer saline by the tested bacteria and this reduction significantly depends on strain types and incubation temperature and time. The reduction of four PAHs varied in the range from 50.94% to 74.51%, 54.48% to 77.98%, 47.35% to 68.84%, and 61.96% to 81.22% for BaA, Chr, BbF and BaP, respectively. The results illustrated that by increasing time and temperature of incubation, binding ratio increased and the highest binding ratio of four PAHs was achieved by L. acidophilus LA-5 at 37 °C. Furthermore, the FTIR analysis was performed for identifying the different functional groups that might participate in the binding of PAHs to bacterial cell wall. The FTIR revealed that cell wall has an important role in removal of BaA, Chr, BbF and BaP from phosphate buffer saline.