Audrey specialises in molecular biology, biochemistry and biotechnology of bacteria and microalgae.
She graduated (M. Sc.) in Biotechnology at the University of Aix-Marseilles (France) in 2009 and worked for a year as a process engineer for a pharmaceutical company, Crucell AG (Switzerland), where she was responsible for the purification procedures, in a cGMP environment, of an inactivated hepatitis A virus to produce the Epaxal(R) vaccine. In 2014, she obtained a Ph.D. in Biotechnology at Lincoln University (New Zealand). Her PhD research focused on understanding the underlying mechanisms by which microorganisms form electroactive biofilms, with applications in electricity production and wastewater treatment.
In 2014, Audrey joined the Climate Change Cluster (C3) as a research associate, contributing to research projects on algal biofuel, seagrass and genetic engineering of microalgae.
She works in close collaboration with Dr Michele Fabris in exploring the potential of microalgae as cell-sized factories for the production of high-value bio-products.
Reviewer for Environmental Science & Technology, Journal of Applied Electrochemistry
Grants and Fellowships;
2012-2014 Dumont d’Urville NZ-France Science & Technology Support Programme: Photosynthetic bioelectrochemical systems, sun energy to bioelectricity
2011-2014 PhD Fellowship from Lincoln Agritech Ltd.: Engineering Microbial Fuel Cell Biofilm Communities
Subject Coordinator of Marine Productivity and Climate Change, UTS
Lead Demonstrator in General Microbiology, UTS
Commault, A.S., Laczka, O., Siboni, N., Tamburic, B., Crosswell, J.R., Seymour, J.R. & Ralph, P.J. 2017, 'Electricity and biomass production in a bacteria-Chlorella based microbial fuel cell treating wastewater', Journal of Power Sources, vol. 356, pp. 299-309.View/Download from: UTS OPUS or Publisher's site
© 2017 Elsevier B.V. The chlorophyte microalga Chlorella vulgaris has been exploited within bioindustrial settings to treat wastewater and produce oxygen at the cathode of microbial fuel cells (MFCs), thereby accumulating algal biomass and producing electricity. We aimed to couple these capacities by growing C. vulgaris at the cathode of MFCs in wastewater previously treated by anodic bacteria. The bioelectrochemical performance of the MFCs was investigated with different catholytes including phosphate buffer and anode effluent, either in the presence or absence of C. vulgaris. The power output fluctuated diurnally in the presence of the alga. The maximum power when C. vulgaris was present reached 34.2 ± 10.0 mW m 2 , double that observed without the alga (15.6 ± 9.7 mW m 2 ), with a relaxation of 0.19 gL 1 d 1 chemical oxygen demand and 5 mg L 1 d 1 ammonium also removed. The microbial community associated with the algal biofilm included nitrogen-fixing (Rhizobiaceae), denitrifying (Pseudomonas stutzeri and Thauera sp., from Pseudomonadales and Rhodocyclales orders, respectively), and nitrate-reducing bacteria (Rheinheimera sp. from the Alteromonadales), all of which likely contributed to nitrogen cycling processes at the cathode. This paper highlights the importance of coupling microbial community screening to electrochemical and chemical analyses to better understand the processes involved in photo-cathode MFCs.
Commault, A., Lear, G., Bouvier, S., Feiler, L., Karacs, J. & Weld, R. 2016, 'Geobacter-dominated biofilms used as amperometric BOD sensors', Biochemical Engineering Journal, vol. 109, pp. 88-95.View/Download from: UTS OPUS or Publisher's site
The biochemical oxygen demand (BOD) of a given water sample is typically measured using a conventional BOD5 assay, which requires 5 days of incubation at 20 °C of the sample with mixed communities of bacteria. The study presents a new type of BOD sensor using a Geobacter-dominated biofilm selected with ethanol as the sole carbon source. Ethanol selected for biofilms with a broader substrate usage than those selected with acetate, making them better for BOD biosensing applications. The biosensor was operated at room temperature with a voltage input of 0.08 V vs SHE (0.36 V vs Ag/AgCl) and calibrated using several dilutions of synthetic wastewater with known BOD concentrations ranging from 174 mg/L to 1200 mg/L. The charge transferred by the biofilm over a reaction time of 17.5 h was linearly correlated (R2 = 0.96) with BOD. Once calibrated, the biosensor was used to measure the BOD of cow's milk with a reproducibility of 94% and an error of only 7.4% compared to BOD5 values. In contrast to the 5 days incubation currently required by standard BOD methods our novel biosensor offers a rapid monitoring alternative for assessments of the BOD of dairy effluent.
Pernice, M., Sinutok, S., Sablok, G., Commault, A., Schliep, M., Macreadie, P., Rasheed, M. & Ralph, P. 2016, 'Molecular physiology reveals ammonium uptake and related gene expression in the seagrass Zostera muelleri', Marine Environmental Research.View/Download from: UTS OPUS or Publisher's site
Tran, N.A.T., Padula, M.P., Evenhuis, C.R., Commault, A.S., Ralph, P.J. & Tamburic, B. 2016, 'Proteomic and biophysical analyses reveal a metabolic shift in nitrogen deprived Nannochloropsis oculata', Algal Research, vol. 19, pp. 1-11.View/Download from: UTS OPUS or Publisher's site
© 2016. The microalga Nannochloropsis oculata is a model organism for understanding intracellular lipid production, with potential benefits to the biofuel, aquaculture and nutraceutical industries. It is well known that nitrogen deprivation increases lipid accumulation in microalgae but the underlying processes are not fully understood. In this study, detailed proteomic and biophysical analyses were used to describe mechanisms that regulate carbon partitioning in nitrogen-deplete N. oculata. The alga selectively up- or down-regulated proteins to shift its metabolic flux in order to compensate for deficits in nitrate availability. Under nitrogen deprivation, proteins involved in photosynthesis, carbon fixation and chlorophyll biosynthesis were all down-regulated, and this was reflected in reduced cell growth and chlorophyll content. Protein content was reduced 4.9-fold in nitrogen-deplete conditions while fatty acid methyl esters increased by 60%. Proteomic analysis revealed that organic carbon and nitrogen from the breakdown of proteins and pigments is channeled primarily into fatty acid synthesis. As a result, the fatty acid concentration increased and the fatty acid profile became more favorable for algal biodiesel production. This advancement in microalgal proteomic analysis will help inform lipid accumulation strategies and optimum cultivation conditions for overproduction of fatty acids in N. oculata.
Commault, A.S., Barrière, F., Lapinsonnière, L., Lear, G., Bouvier, S. & Weld, R.J. 2015, 'Influence of inoculum and anode surface properties on the selection of Geobacter-dominated biofilms', Bioresource Technology, vol. 195, pp. 265-272.View/Download from: UTS OPUS or Publisher's site
This study evaluated the impact of inoculum source and anode surface modification (carboxylate –COO and sulfonamide –SO2NH2 groups) on the microbial composition of anode-respiring biofilms. These two factors have not previously been considered in detail. Three different inoculum sources were investigated, a dry aerobic soil, brackish estuarine mud and freshwater sediment. The biofilms were selected using a poised anode (0.36 V vs Ag/AgCl) and acetate as the electron donor in a three-electrode configuration microbial fuel cell (MFC). Population profiling and cloning showed that all biofilms selected were dominated by Geobacter sp., although their electrochemical properties varied depending on the source inoculum and electrode surface modification. These findings suggest that Geobacter sp. are widespread in soils, even those that do not provide a continuously anaerobic environment, and are better at growing in the MFC conditions than other bacteria.
Commault, A.S., Lear, G. & Weld, R.J. 2015, 'Maintenance of Geobacter-dominated biofilms in microbial fuel cells treating synthetic wastewater', Bioelectrochemistry, vol. 106, no. Part A, pp. 150-158.View/Download from: UTS OPUS or Publisher's site
Geobacter-dominated biofilms can be selected under stringent conditions that limit the growth of competing bacteria. However, in many practical applications, such stringent conditions cannot be maintained and the efficacy and stability of these artificial biofilms may be challenged. In this work, biofilms were selected on low-potential anodes ( 0.36 V vs Ag/AgCl, i.e. 0.08 V vs SHE) in minimal acetate or ethanol media. Selection conditions were then relaxed by transferring the biofilms to synthetic wastewater supplemented with soil as a source of competing bacteria. We tracked community succession and functional changes in these biofilms. The Geobacter-dominated biofilms showed stability in their community composition and electrochemical properties, with Geobacter sp. being still electrically active after six weeks in synthetic wastewater with power densities of 100 ± 19 mWm 2 (against 74 ± 14 mWm 2 at week 0) for all treatments. After six weeks, the ethanol-selected biofilms, despite their high taxon richness and their efficiency at removing the chemical oxygen demand (0.8 gL 1 removed against the initial 1.3 gL 1 injected), were the least stable in terms of community structure. These findings have important implications for environmental microbial fuel cells based on Geobacter-dominated biofilms and suggest that they could be stable in challenging environments.
Commault, A.S., Lear, G. & Weld, R.J. 2014, 'Comment on microbial community composition is unaffected by anode potential', Environmental science & technology, vol. 48, pp. 14851-14852.
Commault, A.S., Lear, G., Novis, P. & Weld, R.J. 2014, 'Photosynthetic biocathode enhances the power output of a sediment-type microbial fuel cell', New Zealand Journal of Botany, vol. 52, pp. 48-59.View/Download from: UTS OPUS or Publisher's site
Conventional microbial fuel cells (MFCs) consist of biological anodes and abiotic cathodes separated by a proton-exchange membrane. The abiotic cathode usually catalyses the reduction of oxygen to produce water by means of expensive catalysts such as platinum.1Supplementary data available online at www.tandfonline.com/10.1080/0028825X.2013.870217
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The cathodic reaction is often limiting in MFCs and researchers are now focusing on efficient, low-cost catalysts to improve oxygen reduction at the cathode. This paper describes a photosynthetic biocathode in a sediment-type MFC constructed without a proton-exchange membrane. The carbon and stainless steel cathode did not contain any catalyst, but was covered in a biofilm composed of a complex community including microalgae and cyanobacteria. Although electroactive species were detected in the cathode biofilm, no biocatalysis of oxygen reduction was observed. Enhancement of the current output was mostly due to the production of pure oxygen near the cathode surface by the photosynthetic biofilm. Photosynthesis could produce dissolved oxygen levels approximately four times higher than oxygen levels obtained by aeration. The MFC was able to generate a maximum power density of 11 mW/m2 (projected anode area) over six months without feeding.
Commault, A.S., Lear, G., Packer, M.A. & Weld, R.J. 2013, 'Influence of anode potentials on selection of Geobacter strains in microbial electrolysis cells', Bioresource Technology, vol. 139, pp. 226-234.View/Download from: UTS OPUS or Publisher's site
Through their ability to directly transfer electrons to electrodes, Geobacter sp. are key organisms for microbial fuel cell technology. This study presents a simple method to reproducibly select Geobacter-dominated anode biofilms from a mixed inoculum of bacteria using graphite electrodes initially poised at 0.25, 0.36 and 0.42 V vs. Ag/AgCl. The biofilms all produced maximum power density of approximately 270 mW m2 (projected anode surface area). Analysis of 16S rRNA genes and intergenic spacer (ITS) sequences found that the biofilm communities were all dominated by bacteria closely related to Geobacter psychrophilus. Anodes initially poised at 0.25 V reproducibly selected biofilms that were dominated by a strain of G. psychrophilus that was genetically distinct from the strain that dominated the 0.36 and 0.42 V biofilms. This work demonstrates for the first time that closely related strains of Geobacter can have very different competitive advantages at different anode potentials.
Commault, A. 2014, 'Engineering microbial fuel cell biofilm communities'.