Genetic redundancy of catechol 1,2-dioxygenase conferred the ability of Rhodococcus opacus PD630 for efficient catecholic compounds degradation

Xinjie Chen; Zhenzhen Cai; Siqi Jiang; Mingyuan Cheng; Xiaoyu Zhang; Fuying Ma; Hongbo Yu; Yuzhou Wu; Fangrui Zhong; Ning Xiao; Shangxian Xie

doi:10.1016/j.biortech.2025.132964

Genetic redundancy of catechol 1,2-dioxygenase conferred the ability of Rhodococcus opacus PD630 for efficient catecholic compounds degradation

Bioresour Technol. 2025 Jul 10:132964. doi: 10.1016/j.biortech.2025.132964. Online ahead of print.

Authors

Xinjie Chen¹, Zhenzhen Cai², Siqi Jiang³, Mingyuan Cheng⁴, Xiaoyu Zhang⁵, Fuying Ma⁶, Hongbo Yu⁷, Yuzhou Wu⁸, Fangrui Zhong⁹, Ning Xiao¹⁰, Shangxian Xie¹¹

Affiliations

¹ Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: imer_cxj@alumni.hust.edu.cn.
² Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: zhenzhen_cai@hust.edu.cn.
³ Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: 490676602@qq.com.
⁴ Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: chengmingyuann@163.com.
⁵ Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: zhangxiaoyu@hust.edu.cn.
⁶ Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: mafuying@hust.edu.cn.
⁷ Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: yuhongbo@hust.edu.cn.
⁸ Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: wuyuzhou@hust.edu.cn.
⁹ Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China. Electronic address: chemzfr@hust.edu.cn.
¹⁰ National Key Laboratory of Non-Food Biomass Energy Technology, Guangxi Academy of Sciences, Nanning 530007, PR China. Electronic address: xiaoninggxas@163.com.
¹¹ Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, PR China; National Key Laboratory of Non-Food Biomass Energy Technology, Guangxi Academy of Sciences, Nanning 530007, PR China. Electronic address: shangxian_xie@hust.edu.cn.

PMID: 40651699
DOI: 10.1016/j.biortech.2025.132964

Abstract

Lignin, a bountiful natural resource, presents challenges in degradation and conversion due to its complex structure. Microorganisms have evolved a "biofunnel" pathway in nature that offers novel insights into lignin valorization. Among the key intermediates in lignin metabolism is catechol, predominantly metabolized by catechol 1,2-dioxygenase (CatA) in these organisms. Understanding the catechol degradation mechanism is pivotal for efficient lignin utilization. Rhodococcus opacus PD630 emerges as a promising host for lignin bioconversion, yet the gene redundancy of catechol 1,2-dioxygenase genes (catA) in this strain is not well understood, hindering a comprehensive grasp of its aromatic compound degradation pathway. This study explores the regulatory mechanisms governing the expression of catA gene duplicates, LPD06568 (catA1) and LPD06742 (catA2), in R. opacus PD630. We compared the functions of the enzymes they encode and discovered that catA2 is responsible for the degradation of excess extracellular catechol in R. opacus PD630. More interestingly, our results also showed that both of the CatAs of R. opacus PD630 could catalyze various catecholic compounds, including those with large side chain groups. Furthermore, catA1 was heterologously expressed in Streptomyces coelicolor M145 and achieved a marked cis, cis-muconic acid production (1.97 g/L) from catechol.

Keywords: Catechol 1,2-dioxygenase; Catecholic compounds; Degradation; Genetic redundancy; Lignin.