Engineering the Physico-Chemical Environment to Enhance the Bioremediation of Developmental Toxicants in Sediment Fungal-Bacterial Biofilms

发育毒性物质，包括多环芳烃(PAHs)、多氯联苯(PCbs) 氯苯酚(如五氯苯酚-PCP)是在许多地方发现的持久性有机污染物 美国各地的危险废物堆放点。这些污染物非常令人担忧，因为它们 它们在食物链中生物积累的潜力以及有害物质具有高毒理学风险 对健康的影响。疏水性有机污染物(HOCs)，如多环芳烃、多氯联苯和多氯联苯尤其 挑战生物修复，因为它们的化学特性降低了它们的生物利用度 微生物因此限制了它们有效生物降解的潜力。由于此限制，自组织 修复策略往往侧重于物理化学方法，包括以下两种方法中的一种 污染介质或污染物的原位固定化通过修正中介隔离，其可以 对当地生态系统产生重大的长期负面影响。在这个项目中，我们提出了一个替代方案 处理方法，包括激发协同细菌-真菌生物膜进行HOC生物降解。 使用这种方法，本土真菌将首先被刺激，利用非特异性胞外降解毒物。 酶并产生更多可供细菌生物利用的副产品，以供随后的生物降解。在使用时 基于产生真菌胞外酶的修复治疗方法并不是全新的， 这个项目的新奇之处在于，我们的重点将放在促进土著人民 与底泥微生物生物膜相关的子囊菌，这一门还没有得到太多的关注 生物修复。该项目的总体目标是通过以下方式最大限度地提高沉积物环境中的特定生物降解率 使用工程复合有机改良剂刺激协同真菌-细菌生物膜的生长。 项目5的一般假设是，物理化学环境可以通过 复合有机改良剂促进细菌-真菌生物膜的形成 本土真菌产生的胞外酶将疏水污染物分解成 更容易进入细菌细胞并被土著分解的副产品 细菌。该项目的具体目标是：1)进行微生物和地球化学表征 用于构建污染沉积物的微生物联合网络模型；2)识别有机物质 支持合作真菌-细菌生物膜的生长并最大限度地促进HOC降解的修饰物 在微观方面；3)设计和测试复合改进剂，以便在沉积物处理方案中交付和； 4)在大尺度中观系统中实施综合修正策略，并验证其有效性。 模拟混合真菌-细菌生物膜的HOC降解。最终，该项目将创建一个框架 在沉积物生物修复和产量的背景下更好地了解真菌-细菌生物膜的合作 HOCs生物修复的现场可翻译方法。

Developmental toxicants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and chlorophenols (e.g., pentachlorophenol - PCP) are persistent organic contaminants found at many hazardous waste sites throughout the United States. These contaminants are of great concern because they present high toxicological risk in terms of their potential for bioaccumulation in the food chain as well as adverse health effects. Hydrophobic organic contaminants (HOCs) such as PAHs, PCBs and PCP are particularly challenging to bioremediate because their chemical characteristics diminish their bioavailability to microorganisms thereby limiting their potential for efficient biodegradation. As a result of this constraint, HOC remediation strategies tend to focus on physical-chemical approaches consisting of either complete excavation of contaminated media or contaminant in situ immobilization via amendment mediated sequestration which can have significant negative long term impacts on local ecosystems. In this project, we propose an alternative treatment approach which consists of stimulating cooperative bacterial-fungal biofilms for HOC biodegradation. Using this approach, indigenous fungi will first be stimulated to degrade toxicants using nonspecific extracellular enzymes and generate by-products more bioavailable to bacteria for subsequent biodegradation. While using remediation treatment approaches based on the production of fungal extracellular enzymes is not entirely new, the novelty of this project resides in the fact that our focus will be directed towards the promotion of indigenous Ascomycetes associated with sediment microbial biofilms, a phylum which has not received much attention for bioremediation. The overall objective of this project is to maximize HOC biodegradation in sediment settings by stimulating the growth of synergistic fungal-bacterial biofilms using engineered composite organic amendments. The general hypothesis for Project 5 is that the physico-chemical environment can be altered using composite organic amendments to stimulate the formation of a cooperative bacterial-fungal biofilms in which indigenous fungi produce extracellular enzymes breaking down hydrophobic contaminants into by-products which are more readily transported into bacterial cells and broken down by indigenous bacteria. The specific aims for this project are to: 1) Perform microbial and geochemical characterizations of contaminated sediments for the construction of a microbial association network model; 2) Identify organic amendments which support the growth of cooperative fungal-bacterial biofilm and maximize HOC degradation in microcosms; 3) Engineer and test composite amendments for delivery in sediment treatment scenarios and; 4) Implement the composite amendment strategy in large-scale mesocosms as well as validate its efficiency for HOC degradation by stimulated mixed fungal-bacterial biofilms. Ultimately, this project will create a framework to better understand cooperative fungal-bacterial biofilms in the context of sediment bioremediation and yield field translatable approaches for the bioremediation of HOCs.