RYAN JENNINGS Biodegradation of Petroleum Hydrocarbons in Marine and Freshwater Environments

Introduction Purpose: to review the process and applications of biodegradation Influencing factors (chemical, temperature, nutrients) Methods of biodegradation

Chemical Composition Has the most significant effect on biodegradability Four ranks of susceptibility (linear alkanes>branched alkanes>small aromatics>cyclic alkanes) Linear – methane, propane Branched – iso, neopentane Aromatics - benzene Cyclic - cyclopropane

Temperature Controls pollutant chemistry and bacterial growth rate Can take place over wide range of temperatures (correlates directly) Most effective in fresh water between 20-30°C

Nutrients Nitrogen, phosphorous, and iron play a vital role Especially important in freshwater Overabundance can hinder biodegradation rate (Chaineau)

Methods - Bioaugmentation The introduction of cultured microorganisms into an environment in which they are capable of biodegrading and mineralizing contaminants. Used when the contaminated site lacks microbes with the catabolic potential or to supplement the indigenous microbes Enlarges gene pool for more genetic variation and faster reproduction (increased biodegradation rate)

Methods - Biostimulation The addition of rate limiting nutrients such as phosphorus, nitrogen, oxygen, and carbon Used when capable microbes are present, but lack nutrients needed to sustain Both bacteria and nutrients introduced through injection wells, slurry walls, or trenches

Conclusion Biodegradation of hydrocarbons is a complex process that relies on the nature of the hydrocarbon, and the environment Main problem with this method is the lack of knowledge on proper bacterial strain use

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