Biodegradation of benzyl butyl phthalate and dibutyl phthalate by Arthrobacter sp. via micellar solubilization in a surfactant-aided system

Abstract

Endocrine-disrupting chemicals (EDCs) like phthalates, mostly discharged in industrial effluents, cause detrimental effects to different life forms, and hence their removal from constituent wastewater is necessary. This study investigated the kinetics of biomass growth and biodegradation of benzyl butyl phthalate (BBP) and dibutyl phthalate (DBP) by Arthrobacter sp. in a surfactant-aided batch system. The effect of different surfactants on aqueous solubility of BBP and DBP was initially examined, which showed that Tween 80 resulted in maximum bioavailability and biodegradation efficiency of the phthalates by the bacterium and without inhibiting the biomass growth. Compared with BBP, DBP was found to be efficiently degraded and supported the bacterial growth within a short period of time over the entire concentration tested in the range 100–1,000 mg L−1. A maximum biomass concentration of 1.819 g L−1 was obtained at 120 h for a DBP concentration of 600 mg L−1 in the presence of Tween 80, which is 5.66-fold increase in biomass concentration as compared with only DBP as the sole substrate. For evaluating the biokinetic parameters involved in DBP biodegradation, the experimental data on DBP utilization were fitted to various kinetic models as reported in the literature. HIGHLIGHTS Biokinetics of surfactant-aided biodegradation of phthalates is reported.; Tween 80 enhanced phthalate biodegradation by improving its bioavailability.; Arthrobacter sp. showed direct uptake of micellar solubilized phthalates.; Efficient biodegradation is achieved overcoming growth inhibition.;

Keywords

• arthrobacter sp.
• bioavailability
• biodegradation
• kinetic modelling
• phthalates
• surfactant-aided system