DBP biodegradation kinetics by Acinetobacter sp.33F in pristine agricultural soil

Abstract

Dibutyl phthalate (DBP) is one of the most widely used plasticizers used in various applications. Due to its toxic effects on the organisms, it has been classified as the highest priority pollutant. It has been observed that DBP can leach out from the landfill and other related sites. This plasticizer ultimately reaches the soil, entering the food chain. Although phthalate esters biodegradation have been reported for different bacteria. But bacteria from the genus Acinetobacter have various advantages as compared to others. They are much more efficient in removal of organic pollutants from the contaminated environments. Therefore, Acinetobacter sp.33F have been selected in the study. This study is focused on DBP biodegradation kinetics by Acinetobacter sp.33F in pristine agricultural soils. The study also compared the results with DBP biodegradation kinetics in minimal media. Biodegradation kinetics studies were performed at 100–2000 mg/L. To model DBP biodegradation kinetics, non-linear models were used. Monod paradigm was used to explain DBP degradation kinetics in minimal medium. The observed values for μ max and K s were 0.0083 (mg/L/h) and 30.57 mg/L. Non-linear Haldane inhibition model was used to explain DBP degradation kinetics in the agricultural soils. μ max , K s , and K i were 0.02008 ± 0.002 (mg/L/h), 176.5 ± 2.3 mg/L and 433.7 ± 3.0 mg/L. This study also demonstrated that Acinetobacter sp.33F could utilize diethyl phthalate (DEP), mono-butyl phthalate (MBP), benzyl butyl phthalate (BBP), di-octyl phthalate (DIOP), and di-decyl phthalate (DIDP) as sole carbon source. The above properties make Acinetobacter sp. 33F a promising candidate for phthalate esters removal from the contaminated agricultural sites. • DBP degradation kinetics demonstrated in minimal media at 100–2000 mg/L. • DBP has inhibitory effect on Acinetobacter sp.33F in the agricultural soil. • Michaelis–Menten paradigm was used to explain kinetics in minimal medium. • Non-linear Haldane inhibition model was used to explain kinetics in the agricultural soil. • Acinetobacter sp.33F can grow on DBP derivatives DEP, MBP, BBP, DIOP, DIDP and PC.