Funding is sought to understand the mechanism of action of microbial-based commercial products marketed to independent oil producers as treatments for paraffin deposition on tank bottoms and oil production equipment. Paraffins, or naturally-occurring long-chain alkanes, form waxy deposits upon petroleum removal from reservoirs and have been implicated in oil field problems that range from reduced oil production to difficulties in the disposal of tank bottom sludges. Numerous strategies have been used in the petroleum industry to combat paraffin deposition. Within the last decade, commercial microbial products have been marketed as safer, cheaper, and more-effective paraffin treatment alternatives to traditional hot oiling/watering or chemical technologies. These products have been touted as beneficial mixtures of facultative anaerobic bacteria which "crack" or biodegrade solid paraffinic substances to shorter-chain alkanes or fatty acids resulting in a less oily product with improved handling characteristics. Despite the recent, widespread use of such products in oil production facilities, little is known about their mechanism(s) of action and only anecdotal evidence exists attesting to their efficacy. Given the proprietary nature of these products, they are typically used under strict manufacturer supervision and are generally not available for serious scientific scrutiny. While it is difficult to evaluate the products directly, the effects of these products could relatively easily be ascertained. We propose to determine the mechanisms of action of such products by analyzing the chemical composition of the oil (including paraffins) and water fractions associated with tank bottoms and oil- recovery wells with or without addition of commercial microbial products. We will use high temperature gas chromatography (GC) to determine whether the oil phase composition has shifted from heavy, paraffinic hydrocarbons to light, recoverable hydrocarbons as a result of commercial product addition. We will interpret these chemical analyses in conjunction with physical measurements such as wax appearance temperatures, cloud points, interfacial tension, and viscosity. Using GC coupled with mass spectrometry, we will examine the water phase associated with the oils for the presence of biosurfactants and known bacterial metabolites of hydrocarbons formed under aerobic and anaerobic conditions in the presence or absence of commercial formulations. Such analyses are a direct outgrowth of previously funded IPEC initiatives. The results of this study will benefit the domestic oil industry because understanding the mechanisms of action of these products will allow the independent producer to determine the conditions under which these products are likely to succeed and to determine if and when the purchase of microbial commercial paraffinic treatments represents a wise expenditure of investment dollars.