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Sanja Aracic (Postdoctoral fellow): Synthetic Electric Microbial Biosensors and the Structure of Electric Biofilms
This project aims to integrate the natural capabilities of microorganisms to detect/respond to specific environmental contaminants and their ability to interact with electrodes. Whole cell systems are being constructed in electric microbes for the detection of range of environmental contaminants to allow continuous real time monitoring. This research is funded by the Office of Naval Research Global.
As part of an FSTE funded project, in collaboration with Dr Vilma Stanisich, the structure and function of Geobacter sulfurreducens biofilms is being investigated. These biofilms are of interest as they are crucial for potential applications of Geobacter sulfurreducens in biodegradation; bioremediation and bioenergy.
Lara Bereza-Malcolm (Doctorial Research Scientist): Synthetic Biology and Environmental Biosensors
Defence Science Institute (DSI) co-funded research project.
DSI co-supervisor: Dr Gulay Mann
Synthetic biology allows the design and construction of biological systems for specific tasks and purposes. Engineering of biological sensors, termed biosensors, is an area within synthetic biology that is currently gaining much attention. A biosensor is a “biological device” (such as a microorganism) that is designed to identify and report specific signals found in the surrounding environment.
My research will focus on the application of synthetic biology to create biosensor technology with an environmental focus. Biosensors will be designed and developed to detect environmentally dangerous contaminants and compounds in both terrestrial and aquatic settings. My investigations will focus on the improvement of previously designed standard biological parts used in construction of synthetic organisms, followed by the design and development of specific novel sensory components. These sensory parts will be combined to create biosensors tailored to detect specific contaminants and compounds of interest. Detection of a specific target will be integrated with a capability of the microorganisms to remediate and remove the contaminate from the environment.
The further development of synthetic biology is important as it allows novel and effective methods to be developed for application to environmental hazardous.
Lara speaks about her work on ABC Radio National's 'The Science Show' with Robyn Williams. Listen to podcast here.
Jen Wiltshire (Doctorial Research Scientist): Rhizosphere Ecology and Function for Heavy Metal Phytoremediation
Soils with elevated heavy metal concentrations occur naturally in many parts of the world. Increasingly human activities including agriculture, mining, and industry are leaving otherwise arable land contaminated with heavy metals. Heavy metals pose particular concerns as they are capable of leeching into water supplies, poisoning both plants and animals and change the indigenous microbial populations thus, methods for their efficient removal from the soil is paramount.
At the heart of my research is how microbes and their interactions in the rhizosphere can affect and increase the efficiency of potential of heavy metal hyperaccumulating plants that can be utilized as cost effective, environmentally friendly cleaning agents. The correct combinations of microbes and plants may restore heavy metal contaminated sites through a process known a phytoremediation. In particular, my research focuses on the rhizosphere of hyperaccumulators and the plant-microbe interactions that take place there. It is hypothesized that rhizosphere microbes, many of which themselves are heavy metal resistant, influence the ability of a plant to hyperaccumulate and are essential for the efficient functioning of the hyperaccumualting aerial tissues. My work incorporates ecological, chemical and biochemical approaches and collaborative research with Professor Tang’s group in the AgriBio building to elucidate the best methods and microbial considerations for optimal phytoremediation.
Jen speaks about her work on ABC Radio National's 'The Science Show' with Robyn Williams. Listen to podcast here.
Rochelle Maile (Doctorial Research Scientist): The use of alternative electron acceptors as a means of addressing microbial induced corrosion of concrete sewer infrastructure
In populations past and present severe disease outbreaks such as Cholera (Vibrio cholera) and Dysentery have caused the deaths of millions. These outbreaks occur when waste disposal/transportation is inadequate or breached resulting in contamination of potable water. Sewer pipes perform the essential role of containing and transporting liquid waste. This facilitates the removal of waste away from where it is produced to a location where it can be treated. However, the creation of sewer infrastructure also created an environment that suited bacteria, which created other problems.
Exploding sewers due to gas produced by methanogenic bacteria was not an uncommon occurrence of times past, foul odours, pipe blockage and pipe collapse were also and still are prevalent issues to wastewater utilities. Now despite over a century of sewer infrastructure development, wastewater utilities are still grappling with the degradation of concrete infrastructure via corrosion.
One of the major causes of concrete sewer pipe corrosion is the result of bacterial driven sulphur cycling. In brief sulphur-reducing bacteria produce hydrogen sulphide (H2S) that is then oxidised by sulphur-oxidising bacteria, resulting in the production of sulphuric acid (H2SO4).
The research I’m undertaking is aimed at using alternative bacterial respiration mechanisms to disrupt the sulphur cycling taking place within the sewer, thus averting the corrosion process.
Lucie Semenec (Doctorial Research Scientist): Genetic Profiling of the Adaptive Evolution in Mixed Species Electrogenic Biofilms
The developing field of electromicrobiology investigates bacteria with novel electrical properties including: extracellularly electron transfer; utilisation of an electrode as an electron as a donor or acceptor; and production of conductive biological material. These microbes are fundamental to the development of Microbial Electric Systems (MESs). MESs can utilise microbes to: generate electrical current; reduce biological waste; bioremediation or; produce a range of organic compounds. MESs have applications in basic research, bioremediation and industrial processes. Fundamental to the operation of an MES is the extracellular transfer of electrons through a microbial biofilm attached to an electrode surface. A further understanding of electron transfer across and between species is required for the optimisation of these processes. It is predicted that pilin (nanowires), outer membrane cytochromes and electron shuttles are important transport mechanisms, however the exact process needs further elucidation especially in mixed species biofilms. My research project will aim to determine the importance of various proteins, polysaccharides and other components through molecular, genetic and function assays.
Although pure culture MES research has lead to a basic understanding of direct electron transfer in several microbial species, extensive research is still required to fully understand and integrate these processes. The purpose of my research project will be to study the adaptive evolution of several electrogenic bacteria such as Geobacter sulfurreducens and Pseudomonas aeruginosa by examining the expression of various genes over time as these mixed cultures adapt to living and evolve in mixed species biofilm utilising an insoluble extracellular electron acceptor such as an electrode. My research will aim to address the specific molecular responses electrogenic microbes have during biofilm formation in mixed cultures, the adaptation sustained competition will cause and provide information to improve MES efficiency.
Overall this research will contribute to the final goal of attaining a highly effective and self-sustaining MES that can be used for bioremediation and alternative energy production in the future.