Chemical and Biochemical Bases for EDTA Biodegradation

这一奖项由美国国家科学基金会化学部环境化学科学项目颁发，旨在支持华盛顿州立大学(WSU)康楚熙教授和孙鲁英教授合作研究乙二胺四乙酸(EDTA)的环境命运。这种化合物通过在工业应用中的广泛使用而被引入环境中。目前，EDTA是包括美国在内的世界各地地表水中含量最丰富的有机污染物。EDTA与有毒的重金属形成强大的络合物并动员它们，这增加了人类的暴露。自然界中存在几种EDTA降解菌。然而，将这些细菌应用于补救是不现实的，因为它们的效率不够高。对细菌EDTA降解途径的关键酶和吸收系统的研究揭示了限制生物降解的因素。这些知识被用来修饰基因以提高催化效率，并帮助产生有效的生物修复解决方案。这项研究为参与的学生提供了酶学、微生物学和生物物理化学方面的跨学科培训，成为西苏里州立大学主要STEM单位之间的重要桥梁。此外，通过现有的NSF资助的K-12外展项目和西苏里州立大学的BXC中心，专业知识被提供给高中教室、当地的帕卢斯发现科学中心和当地的本科生机构。这加强了对不同经济、种族和地理背景的学生的培训。绿僵菌EDTA降解途径中运输和结合蛋白和酶的底物专一性、催化机制和分子相互作用。BNC1.这为设计具有更强降解能力的新型重组系统提供了指导。这些改进的EDTA吸收和代谢基因被克隆到依赖亚磷酸盐的大肠杆菌中，使重组菌株能够降解废水中的EDTA。这种方法的优点不仅在于它对EDTA生物降解的研究做出了贡献，而且还在于它适用于其他人为化合物的类似降解途径。这项研究还阐述了进化适应非天然化学物质的化学基础。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award from the Environmental Chemical Sciences Program in the NSF Division of Chemistry supports a collaborative effort of Professors ChulHee Kang and Luying Xun at Washington State University (WSU) to study the environmental fate of Ethylenediaminetetraacetic acid (EDTA). This compound is being introduced into the environment through extensive use in industrial applications. Currently, EDTA is the most abundant organic pollutant in surface waters around the world, including the US. EDTA forms strong complexes with toxic heavy metals and mobilizes them, which increases exposure of humans. Several EDTA-degrading bacteria exist in nature. However, applying those bacteria in remediation is not practical because they are not efficient enough. Studies of the key enzymes and uptake system for the bacterial EDTA-degradation pathway reveal the factors that limit the biodegradation. This knowledge is used to modify the genes to increase catalytic efficiency and helps generate effective solutions for bioremediation. The research provides the participating students with interdisciplinary training in enzymology, microbiology, and biophysical chemistry, serving as an important bridge among the key STEM units at WSU. In addition, through existing NSF-funded K-12 outreach programs and the BXC Center at WSU, expertise is provided to high school classrooms, the local Palouse Discovery Science Center and local undergraduate institutions. This enhances the training of students of diverse economic, ethnic, and geographic backgrounds.The substrate-specificity, catalytic mechanism and molecular interactions of the transport and binding proteins and enzymes in the EDTA-degradation pathway of Chelativorans sp. BNC1 are investigated. This provides guidance for designing a new recombinant system with enhanced degradation capacity. Those improved EDTA-uptake and metabolizing genes are cloned into phosphite-dependent E. coli to enable the recombinant strain to degrade EDTA in wastewaters. The merit of this approach is not only in its contribution to the study of EDTA biodegradation, but also in its applicability to similar pathways for the degradation of other anthropogenic compounds. The research also addresses the chemical basis of evolutionary adaptations to non-natural chemicals.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.