Phenotype and metabolism alterations in PCB-degrading Rhodococcus biphenylivorans TG9T under acid stress

Aili Li; Jiahui Fan; Yangyang Jia; Xianjin Tang; Jingwen Chen; Chaofeng Shen

doi:10.1016/j.jes.2022.05.016

Phenotype and metabolism alterations in PCB-degrading Rhodococcus biphenylivorans TG9^T under acid stress

J Environ Sci (China). 2023 May:127:441-452. doi: 10.1016/j.jes.2022.05.016. Epub 2022 May 21.

Authors

Aili Li¹, Jiahui Fan¹, Yangyang Jia¹, Xianjin Tang², Jingwen Chen¹, Chaofeng Shen³

Affiliations

¹ Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
² MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
³ Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China. Electronic address: ysxzt@zju.edu.cn.

PMID: 36522076
DOI: 10.1016/j.jes.2022.05.016

Abstract

Environmental acidification impairs microorganism diversity and their functions on substance transformation. Rhodococcus is a ubiquitously distributed genus for contaminant detoxification in the environment, and it can also adapt a certain range of pH. This work interpreted the acid responses from both phenotype and metabolism in strain Rhodococcus biphenylivorans TG9^T (TG9) induced at pH 3. The phenotype alterations were described with the number of culturable and viable cells, intracellular ATP concentrations, cell shape and entocyte, degradation efficiency of polychlorinated biphenyl (PCB) 31 and biphenyl. The number of culturable cells maintained rather stable within the first 10 days, even though the other phenotypes had noticeable alterations, indicating that TG9 possesses certain capacities to survive under acid stress. The metabolism responses were interpreted based on transcription analyses with four treatments including log phase (LP), acid-induced (PER), early recovery after removing acid (RE) and later recovery (REL). With the overview on the expression regulations among the 4 treatments, the RE sample presented more upregulated and less downregulated genes, suggesting that its metabolism was somehow more active after recovering from acid stress. In addition, the response mechanism was interpreted on 10 individual metabolism pathways mainly covering protein modification, antioxidation, antipermeability, H⁺ consumption, neutralization and extrusion. Furthermore, the transcription variations were verified with RT-qPCR on 8 genes with 24-hr, 48-hr and 72-hr acid treatment. Taken together, TG9 possesses comprehensive metabolism strategies defending against acid stress. Consequently, a model was built to provide an integrate insight to understand the acid resistance/tolerance metabolisms in microorganisms.

Keywords: Contaminant degradation; Environmental acidification; Mechanism model; Metabolism pathway; Phenotypic response; Rhodococcus biphenylivorans; Transcription analysis.

MeSH terms

Biodegradation, Environmental
Phenotype
Polychlorinated Biphenyls* / toxicity
Rhodococcus* / metabolism

Substances

Polychlorinated Biphenyls

Supplementary concepts

Rhodococcus pyridinivorans