CHALLENGING ENVIRONMENTAL MIXED SPECIES VS CUPRIAVIDUS METALLIDURANS BIOFILMS WITH HEAVY METALS FOR POTENTIAL USE IN BIOREMEDIATION

Industrial pollution from mining, drilling, hydraulic fracturing since the industrial revolution has made toxic metal ions a seemingly ubiquitous pressure on the environment. The Alberta oil sands are the third largest oil reserve in the world, whose extraction process results in wastes full of heavy metal contaminants that can be toxic to surrounding environments. Biofilm formation by microorganisms have been proposed to protect bacterial populations from toxic metals. Some studies suggest that these microbes can bioaccumulate the metals, which remediates the wastewater and the concentrated metals can be processed for use. This study investigates how a mixed species biofilm of bacteria grown from Alberta oil sands tailings pond water (TPW) compare to a single species biofilm of a bacterium which is known to be tolerant to high concentrations of heavy metals. Cupriavidus metallidurans was tested against the TPW mixed species in increasing metal cation concentrations (Cu²⁺, Ag⁺, Cd²⁺). In all cases, TPW biofilms were found to be more tolerant. However, this tolerance may not be accurate due to a deviation from the protocol when inoculating the TPW biofilms with metal cation solution.