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

摘要 多环芳烃(PAHs)因其毒性、致突变性和致癌性而备受关注。 在超级基金网站上常见的致癌特性。由于它们的化学特性， 多环芳烃往往具有高度的疏水性和顽固性，这使得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，这种混合物需要 工程解决方案，有效地针对多环芳烃，同时最大限度地减少对环境的有害影响 污染物。在多污染物环境中的治疗特别具有挑战性，因为生物修复 针对多环芳烃的策略可以引入环境条件，如含氧微粒子，这可能会增强 金属的浸出潜力和生物可利用性。由于这些挑战，网站经理经常求助于 激进的补救方法，如挖土或疏浚，可能会对环境造成严重的负面影响。 对当地生态系统的长期影响。作为一种替代方法，原位生物修复已被广泛研究。 最大限度地减少对生态的破坏。在上一个资助期，我们开发了一个可推广的框架 利用原位跨王国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 能够合作分解多环芳烃的真菌和细菌菌株的资料库。然而，虽然菌株选择 对于修改后的微生物的有效性来说是一个关键的决定，一些观察到的瞬变 接种后扩增的菌株会显著降低生物修复的长期效果。因此， 一个有待解决的特殊挑战是增强外源基因的长期生存和活性 在复杂的场地条件下的菌株。在这里，我们建议通过开发微生物来应对这一挑战 能够定向输送并提高关键微生物菌株的适合性的胶囊输送载体 实施精准生物修复。微胶囊的渗透性，以及保护性 将内部生物与外部环境分离，使微胶囊对 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的微生物的传递、生存能力和适合性 提高多环芳烃的生物降解性。该项目的具体目标是：1)优化微胶囊的合成 向土壤和沉积物现场的输送、对目标多环芳烃的吸附以及微囊化微生物的生长/功能；2) 开发多环芳烃降解菌的定点微囊化微生物组合并与纯培养的多环芳烃进行比较 降解；以及3)调查微囊化生物强化策略的意外影响 多环芳烃降解产物和共污染金属的地球化学转化评价 与超级基金相关的条件。最终，该项目将产生现场可翻译的方法 超级基金地点多环芳烃与共污染物的生物修复。

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.