MICROCALORIMETRIC ASSESSMENT OF THE BIODEGRADATION KINETICS OF DIETHYL PHTHALATE AND DIBUTYL PHTHALATE BY PURE MICROBIAL CULTURES

Phthalic acid esters (PAEs) are ubiquitous environmental contaminants with documented endocrine-disrupting properties, yet comprehensive understanding of their biodegradation kinetics remains incomplete. This study employed isothermal microcalorimetry to investigate the biodegradation of diethyl phthalate (DEP) and dibutyl phthalate (DBP) by three pure microbial cultures: Escherichia coli, Staphylococcus aureus, and Aspergillus niger.Microcalorimetric thermograms provided real-time metabolic fingerprints, enabling quantification of growth rate constants (k), heat output (Pmax), and inhibition ratios (I). Both PAEs exhibited concentration-dependent inhibition, with DBP demonstrating greater toxicity.