Biodegradation of various phthalic acid esters at high concentrations by Gordonia alkanivorans GH-1 and its degradation mechanism

Abstract

Dibutyl phthalate (DBP) is one of the most widely used phthalic acid esters (PAEs) and can easily be released into the environment and food, posing a significant threat to food safety and human health. In this study, Gordonia alkanivorans GH-1, which was previously isolated from fermented Pixian Doubanjiang in the laboratory, could effectively degrade various PAEs at high concentrations within 48 h, with the degradation efficiency of 2000 mg/L DBP reaching as high as 93.14 % under optimal degradation conditions. Furthermore, the biodegradation mechanism of DBP by strain GH-1 was explored using GC-MS and genomics technology, and the expression of key genes was validated through RT-qPCR. A novel carboxylesterase gene (est1833) was successfully cloned and expressed and the recombinant strain Escherichia coli BL21-p28a-est1833 was demonstrated the capability to degrade DBP. The interaction mechanism between the Est1833 and DBP was predicted by structural modeling and molecular docking. In summary, these findings enhance the understanding of the molecular mechanism of DBP biodegradation by G. alkanivorans GH-1 while providing a scientific foundation for future applications in environmental and food bioremediation.