Phthalic acid esters degradation by a novel marine bacterial strain Mycolicibacterium phocaicum RL-HY01: Characterization, metabolic pathway and bioaugmentation

Lei Ren; Guan Wang; Yongxiang Huang; Jianfu Guo; Chengyong Li; Yang Jia; Sha Chen; John L Zhou; Hanqiao Hu

doi:10.1016/j.scitotenv.2021.148303

Phthalic acid esters degradation by a novel marine bacterial strain Mycolicibacterium phocaicum RL-HY01: Characterization, metabolic pathway and bioaugmentation

Sci Total Environ. 2021 Oct 15:791:148303. doi: 10.1016/j.scitotenv.2021.148303. Epub 2021 Jun 5.

Authors

Lei Ren¹, Guan Wang¹, Yongxiang Huang¹, Jianfu Guo¹, Chengyong Li¹, Yang Jia², Sha Chen³, John L Zhou⁴, Hanqiao Hu⁵

Affiliations

¹ Shenzhen Research Institute of Guangdong Ocean University, Shenzhen 518108, China; College of Coastal Agricultural Sciences, School of Chemistry and Environment, Guangdong Ocean University, Zhanjiang 524088, China.
² National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Zhejiang Provincial Key Lab for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China.
³ Hunan Key Laboratory of Biomass Fiber Functional Materials, School of Life Sciences and Chemistry, Hunan University of Technology, Zhuzhou 412007, China.
⁴ Centre for Green Technology, University of Technology Sydney, 15 Broadway, NSW 2007, Australia.
⁵ Shenzhen Research Institute of Guangdong Ocean University, Shenzhen 518108, China; College of Coastal Agricultural Sciences, School of Chemistry and Environment, Guangdong Ocean University, Zhanjiang 524088, China. Electronic address: huhanqiao@gdou.edu.cn.

PMID: 34118676
DOI: 10.1016/j.scitotenv.2021.148303

Abstract

Phthalic acid esters (PAEs) are one of the most widely used plasticizers and the well-studied environmental pollutants with endocrine disrupting properties. Investigation about PAEs in terrestrial ecosystem has been extensively conducted while the fate of PAEs in marine environment remains underexplored. In this study, a novel di-(2-ethylhexyl) phthalate (DEHP) degrading marine bacterial strain, Mycolicibacterium phocaicum RL-HY01, was isolated and characterized from intertidal sediments. Strain RL-HY01 could utilize a range of PAE plasticizers as sole carbon source for growth. The effects of different environmental factors on the degradation of PAEs were evaluated and the results indicated that strain RL-HY01 could efficiently degrade PAEs under a wide range of pH (5.0 to 9.0), temperature (20 °C to 40 °C) and salinity (below 10%). Specifically, when Tween-80 was added as solubilizing agent, strain RL-HY01 could rapidly degrade DEHP and achieve complete degradation of DEHP (50 mg/L) in 48 h. The kinetics of DEHP degradation by RL-HY01 were well fitted with the modified Gompertz model. The metabolic intermediates of DEHP by strain RL-HY01 were identified by ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis and then the metabolic pathway of DEHP was deduced. DEHP was transformed into di-ethyl phthalate (DEP) via β-oxidation and then DEP was hydrolyzed into phthalic acid (PA) by de-esterification. PA was further transformed into gentisate via salicylic acid and further utilized for cell growth. Bioaugmentation of strain RL-HY01 with marine samples was performed to evaluate its application potential and the results suggested that strain RL-HY01 could accelerate the elimination of DEHP in marine samples. The results have advanced our understanding of the fate of PAEs in marine ecosystem and identified an efficient bioremediation strategy for PAEs-polluted marine sites.

Keywords: Bioaugmentation; Marine microbe; Metabolic kinetics; Mycolicibacterium phocaicum; Phthalic acid esters.

MeSH terms

Biodegradation, Environmental
Dibutyl Phthalate
Diethylhexyl Phthalate*
Ecosystem
Esters
Metabolic Networks and Pathways
Mycobacteriaceae
Phthalic Acids*
Tandem Mass Spectrometry

Substances

Esters
Phthalic Acids
Dibutyl Phthalate
phthalic acid
Diethylhexyl Phthalate

Supplementary concepts

Mycolicibacterium phocaicum