Biodegradation of phthalate esters by Pantoea dispersa BJQ0007 isolated from Baijiu

Abstract Baijiu is a famous Chinese alcoholic beverage and is produced by the co-fermentation of microorganisms with grains as the raw materials. Phthalate esters (PAEs) are toxic chemicals and frequently detected in Baijiu. Identification of microorganisms that could degrade PAEs was recognized as a possible way to solve the contamination. Pantoea spp. are one kind of dominant microorganisms for manufacturing Baijiu. Here, Pantoea dispersa BJQ0007 was isolated from Baijiu fermentation starter and showed the ability in degrading dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, and di-(2-ethylhexyl) phthalate, with di-(2-ethylhexyl) phthalate as the preferred substrate. The whole genome was sequenced with a chromosome of 4,325,134 bp and three plasmids. The metabolic pathway of PAE degradation is proposed with an uncommon metabolic step by converting phthalate monoester to benzoate ester based on metabolic intermediate analysis and genome annotation. Two enzymes responsible for ester bond hydrolysis of PAEs were identified and belonged to enzyme families IV and not defined, respectively. The results revealed PAE degradation of Pantoea species and would promote the safety control of Baijiu products by offering bacterial and enzymatic resources.