Hassan Abbasnezhad

Promoting Microbial Attachment to Oil to Enhance Biodegradation

Microbial adhesion to the oil-water interface is an important parameter in biodegradation of hydrocarbons, to enhance uptake and metabolism of compounds with very low aqueous solubility. Components such as surfactants in the aqueous medium can strongly influence attachment, but past studies of these phenomena have focused on different behaviors of disparate species. Our approach was to study a range of compounds and mechanisms to promote the attachment of a hydrophilic organism, Pseudomonas fluorescens LP6a, to the oil-water interface. Cationic polymers and long chain alcohols both dramatically increased the attachment of P. fluorescens LP6a to n-hexadecane, from near 30% to about 90%, as it characterized by a bacterial adhesion test. Toxicity tests showed that alcohols are appropriate candidates for degradation experiments. The effect of alcohols as adhesion mediators on microbial activity during biodegradation was tested and results demonstrated positive effects of enhanced attachment on biodegradation of non-aqueous compounds such as phenanthrene.

Hassan Abbasnezhad is doing his PhD in Chemical Engineering under the supervision of Dr. Murray Gray.