Development of an optimized naphthenic acid bioremediation strategy in OSPW.

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With worldwide production of light crude oil reserves expected to last ~50 years, there is a need to exploit alternative fuel resources e.g. oil sands. Vast oil-sand resources are already being exploited, resulting in large-scale pollution. They contain complex mixtures of aliphatic and aromatic acids known as 'naphthenic acids' (NAs) that are highly toxic to humans and the environment. During refining, over 1 billion m3 of wastewaters are generated containing high NA concentrations (40-120 mg/L). These toxic wastewaters are stored in large ponds for many years (often decades) before their toxicity is reduced to acceptable levels. NAs can also block or corrode pipes and oil-processing equipment causing further pollution and billion-dollar losses to the industry. High NA concentrations found in oil also reduce the saleable value of petroleum products. Thus, removing NA contamination is of great importance to the global economy, environment and human health. Microbial treatment of NAs has clear cost-environmental advantages. However, the transformation of organic compounds is complex and influenced by a combination of microbial activities/ interactions, biogeochemical factors and the physical-chemical properties of the compound. Our aims and objectives will be to identify the main organisms responsible for NA biodegradation, investigate their interactions, obtain and optimize NA-degrading pure cultures and mixed communities, and validate the rapidity of degradation/ detoxification of NA-contaminated wastewaters. We will follow the degradation process, metabolite accumulation, toxicity, biosurfactant production and microbial community composition. We will design gene probes based on molecular analysis of the main microbes found in the environment, and our new isolates. However, almost nothing is known about the metabolic pathways of NA-degrading microbes (and thus we lack suitable gene probes). The University of Essex (UoE), is at the forefront of research into pollution microbiology, and has significantly advanced of our understanding of NA biodegradation and already begun to elucidate NA catabolic pathways and we will build on our existing knowledge in order to develop suitable gene probes. This study has two potential applications and benefits. A: It will provide a better understanding of the microbes and specific conditions required for the rapid removal of these recalcitrant, toxic compounds from the environment. B: It will provide a better understanding of novel microbial interactions and degradation pathways involved. This study will also have several beneficial outcomes, it will: 1) Provide a cost-effective rapid bioremediation strategy for ecosystems with severe NA contamination 2) Develop cleaner more saleable fuels 3) Identify novel microbes and catabolic pathways with potential applications in cleaner biotechnological processes 4) It will allow gene probes to be developed to determine the degradative potential of other NA-contaminated sites elsewhere 5) Exploit novel fuel resources 6) It may allow possible new discoveries to be made e.g. reveal novel biosurfactants for biotechnological exploitation e.g. biodegradation & microbial enhanced oil recovery, anti-corrosion, oil up-grade etc.