Immobilised cells and enzymes to decontaminate mercury polluted soil: a graduate thesis in applied biomolecular science presented to the Higher Research Degree Office in the Faculty of Science and Engineering, Macquarie University, Australia, Department of Chemistry and Biomolecular Sciences, in partial fulfulment of the requirements for the degree of Master of Research

Mercury is a highly toxic heavy metal with no biological function. High mercury pollution remediation costs are driven by energy, engineering and site specific imposts. A sufficiently inexpensive and practicable method is required before mercury can be removed at the scale required. Nature has evolved such a mechanism - enzymatic reduction and volatilisation. This research into harnessing the natural biological strategy uses two immobilising techniques that incorporate this volatising concept. In one approach live cells known to volatise mercury were immobilised on a naturally occurring bulk substrate, zeolite, via encapsulation in a biopolymer. The research finds the cells remain active even after prolonged storage, and retain their ability to volatise mercury. In the second approach the mercuric reductase enzyme was immobilised on zeolite via a solid binding peptide, and retained functionality. A significant driver of this study is an effort to overcome drawbacks with current remediation methods that are expensive, impractical and/or permanently detrimental to soils. The research lays the pathway to a unique environmentally friendly and practical remediation method that can be applied directly to soil with no detrimental effects. These immobilising strategies on the bulk natural substrate zeolite underpin potential new applications to ameliorate mercury contamination.