Electronic Thesis and Dissertation Repository


Master of Engineering Science


Chemical and Biochemical Engineering




In this study a simulated fuel storage tank was used to investigate the effect of biodiesel concentration on biodegradation of polyethylene. This research is relevant in the field of fuel storage. The simulated storage system consisted of a number of identical conical flasks. Each flask was comprised of two layers, an upper one consisting of a fuel blend of diesel with biodiesel in concentrations ranging from 0 to 100% of biodiesel and the bottom layer containing an aqueous mineral media inoculated with a community obtained from a real fuel storage facility. Polyethylene slabs cut to a specific size were immersed in the aqueous layer and were aged for 200 days, the system was kept at environmental temperature of approximate 25°. The microbial composition of the aqueous layer, biofilm development on polyethylene slabs and changes in polymer surface were studied. The results in this study confirm that biodiesel in a mixture of diesel-biodiesel can affect both the composition and metabolic capabilities of microbial communities in diesel storage tanks. Biodiesel can also affect the biofilm community structure and the biodegradation of polyethylene. However, microorganisms induced only surface damage and it is unlikely that in the short term it represents a risk for the infrastructure.