CAREER: Enzyme Expression in Microbial Communities Oxidizing Emerging Water Contaminants: An Integrated Research and Education Plan

CBET-1255021 Shaily Mahendra加州大学洛杉矶分校该项目将研究微生物如何降解和解毒危险化学品，这些化学品在供水中出现，但目前不受管制。 产生单加氧酶的细菌具有独特的生物降解多种难降解化合物的能力，如氯化溶剂、石油烃、杀虫剂和醚。 这些酶含有过渡金属，以促进生物化学氧化还原反应中的电子转移，并且它们的效率可以根据特定金属的可用性而在数量级上变化。 1，4-二氧六环是一种可能的致癌物，其生物降解是由单加氧酶介导的，将被用作本研究中的模型新兴污染物。 1，4-二氧六环是氯化溶剂的稳定剂、纺织纤维加工中的润湿剂以及多种个人护理产品的副产品。 在混合废物和污染场地中，铁、钴、铜、镍、锌等金属和其他有机物与1，4-二氧六环共存，并将影响单加氧酶以及1，4-二氧六环的生物降解速率。 在这项研究中收集的数据将证明金属和地球化学条件对1，4-二氧六环生物降解的影响，通过在液体培养物中生长的细菌以及在沙子或碳基表面上生长的生物膜。 将设计新的比色和遗传工具，以快速估计在不同类型的生长和环境条件下相关的生物降解酶和耐金属酶的活性。 将通过使用基因芯片和强大的DNA测序方法评估积极参与1，4-二氧六环生物降解的微生物群落组成的变化。 传统的清洁技术价格昂贵，消耗资源和能源，或将污染从一个地方转移到另一个地方。 生物修复可能是从土壤、沉积物、地下水和废水中去除新污染物的一种技术和财政上可行的选择。 该项目将提供关于最近受到管理机构审查的环境污染物的转归和转化的关键数据。 PI将利用这项研究的结果，与环境工程专业人员合作，为工业和军事废物流设计生物修复和监测系统。 研究工作将与指导不同背景的学生在初中，高中，本科和研究生水平相结合。 除了出版物和在科学会议上的介绍外，研究结果将纳入环境工程和微生物学课程。

CBET-1255021Shaily MahendraUniversity of California, Los AngelesThis project will investigate how microbes can degrade and detoxify hazardous chemicals which have an emerging, yet currently unregulated, presence in water supplies. Bacteria that produce monooxygenase enzymes are uniquely capable of biodegrading a variety of recalcitrant compounds, such as chlorinated solvents, petroleum hydrocarbons, pesticides, and ethers. These enzymes contain transition metals to facilitate transferring electrons in biochemical redox reactions, and their efficiency can vary over orders of magnitude depending upon the availability of specific metals. 1,4-Dioxane, a probable carcinogen, whose biodegradation is mediated by monooxygenases, will be used as a model emerging contaminant in this study. 1,4-Dioxane is a stabilizer of chlorinated solvents, a wetting agent in the processing of textile fibers, and a byproduct in several personal care products. In mixed wastes and contaminated sites, metals such as iron, cobalt, copper, nickel, zinc, and other organics coexist with 1,4-dioxane and will influence the monooxygenase enzymes as well as 1,4-dioxane biodegradation rates. Data collected in this research will demonstrate the effects of metals and geochemical conditions on 1,4-dioxane biodegradation by bacteria growing in liquid cultures as well as biofilms growing on sand or carbon-based surfaces. Novel colorimetric and genetic tools will be designed to rapidly estimate the activities of relevant biodegradative and metal-resistant enzymes under different types of growth and environmental conditions. Changes in composition of microbial communities actively engaged in 1,4-dioxane biodegradation will be assessed by using gene chips and powerful DNA sequencing methods. Conventional clean-up technologies are expensive, consume resources and energy, or move the pollution from one place to another. Bioremediation could be a technically and financially viable option for removing emerging contaminants from soil, sediments, groundwater, and wastewater. This project will provide critical data on fate and transformations of environmental contaminants that have recently fallen under the scrutiny of regulatory agencies. The results from this study will be leveraged by the PI, in collaboration with environmental engineering professionals, to design bioremediation and monitoring systems for industrial and military waste streams. Research efforts will be coupled with mentoring students of diverse backgrounds at the middle school, high school, undergraduate, and graduate levels. In addition to publications and presentations at scientific meetings, the findings will be integrated with curricula of environmental engineering and microbiology courses.