Project 5: Microencapsulation Delivery Vehicles for the Implementation of Precision Bioremediation at PAH-Contaminated Superfund Sites

摘要 多环芳烃（PAHs）是一种非常受关注的污染物，因为它们具有毒性、致突变性和 致癌物质，通常在超级基金网站遇到的。由于它们的化学特性， 多环芳烃往往是高度疏水性和不可降解的，使它们成为具有挑战性的修复目标。PAH- 受影响的地点也经常富含来自相关行业的有毒金属，这些混合物需要 工程解决方案，有效地针对多环芳烃，同时最大限度地减少有害的环境影响， 污染物。多污染物环境中的处理特别具有挑战性，因为生物修复 针对多环芳烃的策略可以引入环境条件，例如可能增强毒性的微环境 金属的浸出潜力和生物利用度。由于这些挑战，现场管理人员经常求助于 激烈的补救方法，如土壤挖掘或疏浚，这可能会产生重大的负面长期- 对当地生态系统的长期影响。原位生物修复作为一种替代方法得到了广泛的研究 生态破坏最小。在上一个资助期间，我们制定了一个通用框架， 利用原位跨界微生物相互作用对多环芳烃进行精确的生物修复。我们创建了一个 真菌和细菌菌株库，可以合作分解多环芳烃。然而，尽管菌株选择 是一个关键的决定，要作出的有效性修正微生物，观察到的短暂性，一些 接种后增加的菌株可显著降低生物修复的长期有效性。因此，在本发明中， 一个有待解决的特殊挑战是增强的外源性 在复杂的现场条件下。在此，我们建议通过开发微生物来应对这一挑战。 包封递送载体，其能够靶向递送并增加关键微生物菌株的适合性， 实施精准生物修复。微胶囊的渗透性，以及保护性的 内部生物体与外部环境的分离，使得微胶囊对 部署到自然环境和实施精确的生物修复。我们假设 微胶囊的使用将改善增强微生物的递送、存活力和适应性， 改善PAH生物降解。本项目的具体目标是：1）优化微胶囊合成， 向土壤和沉积物中的释放、目标多环芳烃的吸附以及微生物的生长/功能; 2） 开发特定地点的PAH降解剂微生物群，并与PAH纯培养物进行比较 降解;和3）调查微胶囊化生物强化策略的意外影响， 评估多环芳烃降解产物和共污染金属的地球化学转化， 超级基金相关条件。最终，这个项目将产生现场可翻译的方法， 生物修复的多环芳烃在超级基金网站与共污染物。

Abstract Polycyclic aromatic hydrocarbons (PAHs) are contaminants of great concern due to their toxic, mutagenic and carcinogenic properties that are commonly encountered at Superfund sites. Due to their chemical characteristics, PAHs tend to be highly hydrophobic and recalcitrant, making them challenging targets for remediation. PAH- impacted sites are also frequently enriched with toxic metals from related industries, and such mixtures require engineering solutions that effectively target PAHs while minimizing deleterious environmental impacts on co- contaminants. Treatments in multi-contaminant settings are particularly challenging because bioremediation strategies aimed at PAHs can introduce environmental conditions such as oxic microniches that may enhance the leaching potential and bioavailability of metals. Because of these challenges, site managers often resort to drastic remediation approaches such as soil excavation or dredging, which can have significant negative long- term impacts on local ecosystems. In situ bioremediation has been widely studied as an alternative approach with minimal ecological disruption. During the last funding period, we developed a generalizable framework for the precision bioremediation of PAHs that harnesses in situ cross-kingdom microbial interactions. We created a library of fungal and bacterial strains that could work cooperatively to breakdown PAHs. Yet, while strain selection is a pivotal decision to be made for the effectiveness of the amended microbes, the observed transience of some augmented strains after inoculation can significantly reduce the long-term effectiveness of bioremediation. Thus, a particular challenge that remains to be solved is the long-term survival and activity of augmented exogenous strains under complex site conditions. Herein, we propose to address this challenge by developing microbial encapsulation delivery vehicles that enable targeted delivery and increased fitness of key microbial strains for the implementation of precision bioremediation. The permeability of the microcapsule, alongside the protective separation of the internal organisms from the external environment, makes microcapsules attractive for deployment to natural environments and for the implementation of precision bioremediation. We hypothesize that the use of microcapsules will improve delivery, viability and fitness of the augmented microbes thereby improving PAH biodegradation. The specific aims for this project are to: 1) Optimize microcapsule synthesis for delivery to soil and sediment sites, sorption of target PAHs, and growth/function of encapsulated microbes; 2) Develop site-specific encapsulated microbial consortia of PAH degraders and compare to pure cultures for PAH degradation; and 3) Investigate unintended impacts of the microencapsulated bioaugmentation strategy through evaluation of PAH degradation products and geochemical transformations of co-contaminant metals in Superfund-relevant conditions. Ultimately, this project will yield field translatable approaches for the bioremediation of PAHs at Superfund sites with co-contaminants.