Construction of a myoglobin scaffold-based biocatalyst for the biodegradation of sulfadiazine and sulfathiazole

• Published in: Journal of hazardous materials 2024-03, Vol.465, p.133147, Article 133147
• Main Authors: Zhang, Weikang, Lin, Yingwu, Meng, Xiangmin, Wang, Qiaoning, Chen, Lingxin, Xu, Jiakun
• Format: Article
• Language: English
• Subjects: Biocatalysis; Biodegradation; Directed evolution; Myoglobin; Sulfonamides
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.133147

Sulfonamide antibiotics, a family of broad-spectrum antibiotic drugs, are increasingly used in aquaculture and are frequently detected in aquatic environments. This poses a potential threat to organisms and may cause the evolution of antimicrobial resistance. Therefore, it is important to develop an environmentally friendly and efficient biocatalyst to degrade sulfonamides (SAs) such as sulfadiazine (SD) and sulfathiazole (ST). Here, we realized the direct and efficient degradation of SD and ST using a hydrogen peroxide-dependent artificial catalytic system based on myoglobin (Mb). The arrangements of amino acids at positions 29, 43, 64, and 68 were found to influence catalytic activity. An L29H/H64D/V68I myoglobin mutant showed the best catalytic efficiency (i.e., kcat/Km = 720.42 M−1 s−1) against SD. Next, mutant H64D/V68I showed the best degradation rate against SD (i.e., 91.45 ± 0.16%). Moreover, L29H/H64D/V68I Mb was found to efficiently catalyze ST oxidation (kcat/Km = 670.08 M−1 s−1), while H64D/V68I had the best degradation rate against ST (i.e., 99.45 ± 0.23%). Our results demonstrate that SAs can be efficiently degraded by artificial peroxygenases constructed using a myoglobin scaffold. This therefore provides a simple and economical method for the biodegradation of SD and ST. [Display omitted] •Efficient bio-degradation of sulfonamides was realized by a H2O2-dependent artificial catalyst based on myoglobin.•H64D/V68I myoglobin mutant removed 91.45 ± 0.16% SDZ and 99.45 ± 0.23% ST.•The transformation pathways of SD and ST were speculated.•The catalytic ability of the biocatalyst could be fine-tuned by changing the arrangement of amino acids in the active site.