Development of Passive and Sustainable Cometabolic Systems to Treat Complex Contaminant Mixtures by Encapsulating Microbial Cultures and Slow Release Substrates in Hydrogels

开发被动和可持续的共代谢系统，通过将微生物培养物和缓释底物封装在水凝胶中来处理复杂的污染物混合物

• 批准号: 10514619
• 负责人: MICHAEL R. HYMAN
• 金额: $ 27.44万
• 依托单位: OREGON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-16 至 2025-10-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10514619
• 关键词: 3-Dimensional; Aerobic; Alcohols; Alkanes; Bacteria; Bioremediations; Carcinogens; Catabolism; Cells; Centers for Disease Control and Prevention (U.S.); Chloroform; Complement; Complex; Complex Mixtures; Crosslinker; Development; Dichloroethylenes; Diffuse; Dimethylnitrosamine; Dioxanes; Encapsulated; Enzymes; Ethylene Dichlorides; Ethylenes; Experimental Designs; Formulation; Generations; Genome; Goals; Growth; Human; Hydrocarbons; Hydrogels; In Situ; Label; Laboratories; Life Cycle Stages; Measurement; Mechanics; Methods; Methylene Chloride; Mixed Function Oxygenases; Modeling; N-nitrosodimethylamine; Output; Permeability; Physiological; Polymers; Process; Proteome; Proteomics; Public Health; Pump; Research; Rhodococcus; Sampling; Site; Soil; Solvents; Starvation; Statistical Models; System; Techniques; Technology; Temperature; Test Result; Testing; Tetrachloroethylene; Toxic effect; Trichloroethanes; Trichloroethylene; United States; Validation; Vinyl Chloride; Water Supply; Work; alcohol effect; anthropogenesis; cost; drinking water; experimental study; gellan; ground water; interest; large scale production; materials science; microbial; microorganism; remediation; scale up; screening; volatile organic compound

Groundwater contamination with volatile organic compounds (VOCs) is a widespread issue throughout the United States. Over 50% of more than 3500 groundwater samples collected from 98 major drinking water supply aquifers from 1985-2001 contained at least one anthropogenic contaminant, with VOCs detected most frequently. Among the top 15 VOCs detected, eight were chlorinated aliphatic hydrocarbons (CAHs): chloroform (CF), perchloroethylene (PCE), trichloroethylene (TCE), 1,1,1-trichloroethane (1,1,1-TCA), cis-1,2-dichloroethylene (cis-DCE), trans-1,2-dichloroethylene (trans-DCE), dichloromethane (DCM), and 1,1-dichloroethane (1,1-DCA). All of these CAHs are listed by the Centers for Disease Control and Prevention as being likely human carcinogens. Of increasing concern are emerging co-contaminants, such as 1,4-dioxane (1,4-D), which is also a likely human carcinogen. Common remediation techniques, such as pump-and-treat, are not sustainable for treating contaminant mixtures that slowly diffuse from low permeability zones in the subsurface. These issues highlight the need for long-term, passive, and economical remediation techniques. Passive and sustainable systems are proposed for the aerobic cometabolism of emerging contaminants, such as 1,4-D, that are mixed with CAHs. These passive systems will be created by co-encapsulating axenic bacterial cultures with a slow release compound (SRC) in hydrogel beads. The SRC will slowly hydrolyze in the beads to produce an alcohol, which will serve as a microbial growth substrate and as an inducer for non-specific contaminant-degrading monooxygenases. Groundwater contaminants will diffuse into the hydrogels where they will be cometabolically transformed to non-toxic products. In preliminary studies, the alkane-oxidizing bacterium Rhodococcus rhodochrous ATCC 21198 was co-encapsulated with an orthosilicate SRC in a gellan gum hydrogel. Continuous degradation of 1,1,1-TCA, cis-DCE, and 1,4-D was maintained for over 300 days. In the proposed work, proteomic analyses of this model bacterium will be performed to identify the active monooxygenases and to characterize the enzymatic and physiological changes that ultimately limit the long-term activity of this bacterium in the encapsulated systems. Genome- enabled approaches will also be used to rationally identify other microorganisms with different monooxygenase compliments that can also be co-encapsulated with SRCs to achieve the degradation of a broad range of emerging contaminants. Material science research will determine how to produce hydrogels beads that maintain mechanical integrity for extended periods, focusing on processes that can be easily scaled-up for producing large quantities of beads needed for in-situ treatment. The beads will then be used in different platforms at the laboratory scale to create passive permeable reactive barriers. The hydrogel beads might also be used for treating contaminated soils and sediments and other emerging contaminants.

挥发性有机化合物 (VOC) 地下水污染是整个地区普遍存在的问题 美国。从 98 个主要饮用水源地采集的 3500 多个地下水样本中超过 50% 1985-2001 年的供水含水层至少含有一种人为污染物，并检测到挥发性有机化合物 最频繁。在检测到的前 15 种 VOC 中，有 8 种是氯化脂肪烃 (CAH)： 氯仿 (CF)、全氯乙烯 (PCE)、三氯乙烯 (TCE)、1,1,1-三氯乙烷 (1,1,1-TCA)、 顺式1,2-二氯乙烯(cis-DCE)、反式1,2-二氯乙烯(trans-DCE)、二氯甲烷(DCM)、 和1,1-二氯乙烷(1,1-DCA)。所有这些 CAH 均由疾病控制中心列出 预防可能的人类致癌物。越来越令人担忧的是新出现的共同污染物，例如 1,4-二恶烷 (1,4-D)，它也是一种可能的人类致癌物。常见的修复技术，例如 作为泵送处理法，对于处理从低处缓慢扩散的污染物混合物来说是不可持续的。 地下的渗透性区域。这些问题突出表明需要长期、被动和 经济的修复技术。 建议采用被动和可持续的系统来进行新兴污染物的有氧共代谢，例如 如 1,4-D，与 CAH 混合。这些无源系统将通过共同封装无菌来创建 水凝胶珠中含有缓释化合物 (SRC) 的细菌培养物。 SRC会慢慢水解 在珠子中产生酒精，该酒精将作为微生物生长底物和诱导剂 非特异性污染物降解单加氧酶。地下水污染物将扩散到 水凝胶将通过代谢转化为无毒产品。在初步研究中， 烷烃氧化细菌红红球菌 ATCC 21198 与 结冷胶水凝胶中的原硅酸盐 SRC。 1,1,1-TCA、cis-DCE 和 1,4-D 的连续降解 维护了300多天。在拟议的工作中，该模型细菌的蛋白质组学分析将 进行鉴定活性单加氧酶并表征酶学和生理学 最终限制了这种细菌在封装系统中的长期活性的变化。基因组- 可行的方法也将用于合理地识别其他具有不同特征的微生物。 单加氧酶补充物也可以与 SRC 共同封装，以实现单加氧酶的降解 范围广泛的新兴污染物。材料科学研究将决定如何生产水凝胶 长时间保持机械完整性的珠子，专注于可以轻松地进行的过程 扩大规模以生产大量原位处理所需的珠子。然后将使用珠子 在实验室规模的不同平台上创建被动渗透反应屏障。水凝胶 珠子还可用于处理受污染的土壤和沉积物以及其他新出现的污染物。