School of Chemical & Environmental Engineering, China University of Mining and Technology (Beijing), 100083 Beijing, China.
School of Chemical & Environmental Engineering, China University of Mining and Technology (Beijing), 100083 Beijing, China.
J Hazard Mater. 2024 May 5;469:134049. doi: 10.1016/j.jhazmat.2024.134049. Epub 2024 Mar 16.
A newly isolated ureolytic bacteria, Brucella intermedia TSBOI, exhibited microbially induced calcite precipitation (MICP) which is a promising technique for the remediation of heavy metals in polluted environments. Brucella intermedia TSBOI achieved 90-100% removal of 1 mmol/L Cu/Pb/Zn within 72 h. A distinctive feature lies in B. intermedia TSBOI's capacity for the transport and hydrolysis of urea, considered to be critical for its strong urease activity. This study explored the mechanisms of this capacity at the genetic, molecular and protein levels through complete genome sequencing, molecular docking and enzymatic reaction kinetics. The results revealed that, for urea hydrolysis, B. intermedia TSBOI exhibited a comprehensive urease gene cluster, with the key gene ureC demonstrating an absolute expression level approximating to 4 × 10 copies/RNA ng under optimal conditions. Results also confirmed the strong spontaneous, energy-independent binding ability of it's urease to urea, with the lowest Gibbs free energy binding site linking to the three amino acids, alanine, asparagine and serine. The urea transport gene yut presented and expressed, with the absolute expression enhanced in response to increasing urea concentrations. The significant positive correlation between ureC/yut expression levels and urease activity provided a theoretical basis for B. intermedia TSBOI's heavy metal bioremediation potential. ENVIRONMENTAL IMPLICATION: Heavy metals (Cu, Pb and Zn) were studied in this study. Heavy metals are hazardous due to their toxicity, persistence, and ability to bioaccumulate in living organisms. They can cause severe health issues, harm ecosystems, and contaminate air, water, and soil. A novel ureolytic bacteria, Brucella intermedia TSBOI, exhibited microbially induced carbonate precipitation capability was isolated which removed 90-100% of 1 mmol/L Cu/Pb/Zn within 72 h. Its advantages in urea hydrolysis and transport facilitate the remediation of actual heavy metal contaminated environments.
一种新分离的脲酶细菌布鲁氏中间亚种 TSBOI 表现出微生物诱导碳酸钙沉淀（MICP）的能力，这是一种有前途的修复受污染环境中重金属的技术。布鲁氏中间亚种 TSBOI 在 72 小时内实现了 1 mmol/L Cu/Pb/Zn 的 90-100%去除。其独特之处在于布鲁氏中间亚种 TSBOI 具有运输和水解尿素的能力，这被认为是其强脲酶活性的关键。本研究通过全基因组测序、分子对接和酶促反应动力学，从遗传、分子和蛋白质水平上探讨了这种能力的机制。结果表明，对于尿素水解，布鲁氏中间亚种 TSBOI 表现出全面的脲酶基因簇，关键基因 ureC 在最佳条件下的绝对表达水平接近 4×10 拷贝/RNA ng。结果还证实了其脲酶对尿素的自发、能量独立的强结合能力，最低吉布斯自由能结合位点与丙氨酸、天冬酰胺和丝氨酸这三个氨基酸相连。尿素转运基因 yut 存在并表达，其绝对表达水平随尿素浓度的增加而增强。ureC/yut 表达水平与脲酶活性之间的显著正相关为布鲁氏中间亚种 TSBOI 的重金属生物修复潜力提供了理论依据。环境意义：本研究研究了重金属（Cu、Pb 和 Zn）。重金属由于其毒性、持久性和在生物体中生物累积的能力而具有危害性。它们会导致严重的健康问题，破坏生态系统，并污染空气、水和土壤。一种新的脲酶细菌布鲁氏中间亚种 TSBOI 被分离出来，具有微生物诱导碳酸盐沉淀能力，可在 72 小时内去除 90-100%的 1 mmol/L Cu/Pb/Zn。其在尿素水解和运输方面的优势有利于实际重金属污染环境的修复。
