Audrey is a core member of the Algal Biosystems and Biotechnology group in the Climate Change Cluster (C3) at UTS, with over 7 years of experience in algal biotechnology. Her two main research topics are (i) the bioremediation of wastewaters (domestic and industrial) and (ii) the production of high value compounds from the green microalgae Chlamydomonas reinhardtii with a focus on (tri)terpenoids.
Prior to joining UTS:C3 in 2014, Audrey completed a M.Sc. in Biotechnology at the University of Aix-Marseilles (France). In 2010, she worked 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 for the Epaxal(R) vaccine production. In 2014, she obtained a Ph.D. in Biotechnology at Lincoln University (New Zealand), where she was the recipient of a PhD Industry Fellowship funded by Lincoln Agritech Ltd. Over time, she has developed skills and interest in microalgae cultivation, biochemistry, molecular biology, protein expression and purification.
• Journal reviewer
International Journal of Molecular Sciences; Environmental Science & Technology;
Journal of Applied Electrochemistry; Water; Bioresource Technology; Journal of Power
Sources; Environmental Science and Pollution Research.
• Grant reviewer
Reviewer for the 2017 Scientific Mobility Program of the French Embassy (five grant applications).
Organisation of 21 catered seminars for UTS:C3 seminar series
Assessment of several UTS PhD students DSP2 and final seminars
Assessment of two Honours theses
Assessment of one PhD thesis (Libertus Darus, The University of Queensland).
- Algal biotechnology
- Algal terpenoid metabolism
- Metabolism engineering
- Algal molecular biology
Subject Coordinator of Marine Productivity and Climate Change (91156), UTS
Guess lecturer for Environmental Biotechnology (91818), UTS
Commault, AS, Kaur Walia, N, Fabris, M, Barolo, L, Siboni, N, Adriaans, J, Ralph, PJ & Pernice, M 2020, 'Effect of biphasic temperature regime on therapeutic recombinant protein production in the green alga Chlamydomonas reinhardtii', Algal Research, vol. 50.View/Download from: Publisher's site
© 2020 Elsevier B.V. Microalgae are increasingly being considered for recombinant protein production because of low cultivation costs, absence of endotoxins and insusceptibility to human infectious agents. Despite these advantages, the yield of recombinant protein produced in microalgae is still low compared to more established expression systems and optimization at the genetic and cultivation levels is required for this new system to be economically viable. This study investigates the effect of biphasic temperature regimes on the yield of recombinant human interferon alpha 2a (IFN-α2a), a therapeutic protein known for its anti-cancer and anti-viral properties, produced by the model green alga Chlamydomonas reinhardtii (Cr.IFN-α2a). Biphasic growth is commonly employed to increase recombinant protein production in mammalian cell lines used for commercial production of therapeutic proteins, with a lowering of the temperature resulting in higher yields. In this study, lowering the temperature from 25 °C to 15 °C in mid-exponential growth phase increased the accumulation of Cr.IFN-α2a by 3.3-fold while it slowed down the growth of the three C. reinhardtii transgenic lines tested. In contrast, a rise of temperature from 25 °C to 35 °C accelerated cell growth, while negatively impacting the production of Cr.IFN-α2a. After a two-step chromatography purification, the Cr.IFN-α2a produced was estimated to be 53% pure with a yield of 90 μg/L of culture. The amino acid sequence of Cr.IFN-α2a was confirmed by mass spectrometry. However, the anti-viral activity of Cr.IFN-α2a was found to be 10 times lower than the human IFN-α2a standard produced using E. coli when challenged in a cytopathic effect (CPE) assay, likely due to the formation of aggregates. While the molecular mechanisms driving the accumulation of Cr.IFN-α2a at lower temperature remains unclear, our results support that reducing the temperature at the peak of expression is a valid strategy to increase the yield o...
Nguyen, LN, Commault, AS, Kahlke, T, Ralph, PJ, Semblante, GU, Johir, MAH & Nghiem, LD 2020, 'Genome sequencing as a new window into the microbial community of membrane bioreactors - A critical review.', Science of the Total Environment, vol. 704, pp. 135279-135279.View/Download from: Publisher's site
Recent developed sequencing techniques have resulted in a new and unprecedented way to study biological wastewater treatment, in which most organisms are uncultivable. This review provides (i) an insight on state-of-the-art sequencing techniques and their limitations; (ii) a critical assessment of the microbial community in biological reactor and biofouling layer in a membrane bioreactor (MBR). The data from high-throughput sequencing has been used to infer microbial growth conditions and metabolisms of microorganisms present in MBRs at the time of sampling. These data shed new insight to two fundamental questions about a microbial community in the MBR process namely the microbial composition (who are they?) and the functions of each specific microbial assemblage (what are their function?). The results to date also highlight the complexity of the microbial community growing on MBRs. Environmental conditions are dynamic and diverse, and can influence the diversity and structural dynamics of any given microbial community for wastewater treatment. The benefits of understanding the structure of microbial communities on three major aspects of the MBR process (i.e. nutrient removal, biofouling control, and micropollutant removal) were symmetrically delineated. This review also indicates that the deployment of microbial community analysis for a practical engineering context, in terms of process design and system optimization, can be further realized.
Nguyen, LN, Truong, MV, Nguyen, AQ, Johir, MAH, Commault, AS, Ralph, PJ, Semblante, GU & Nghiem, LD 2020, 'A sequential membrane bioreactor followed by a membrane microalgal reactor for nutrient removal and algal biomass production', Environmental Science: Water Research and Technology, vol. 6, no. 1, pp. 189-196.View/Download from: Publisher's site
© 2019 The Royal Society of Chemistry. A hybrid process combining a single compartment aerobic membrane bioreactor (MBR) and a membrane microalgal reactor (MMR) was evaluated for nutrient removal and microalgal biomass production. When operated without biomass extraction, the microalgal biomass in the MMR reached 920 mg L-1 on day 18 and then collapsed, rendering nutrient removal ineffective. Stable operation of the MMR was achieved by regular biomass extraction (i.e. 1/30 of the microalgal biomass in the reactor daily). The biomass production at steady state was approximately 26 g m-3 d-1. The NO3- and PO43- uptake values by microalgae were 4.0 ± 1.1 and 1.5 ± 0.9 g m-3 d-1, respectively. A facile flocculation and separation technique capable of recovering 98% microalgal biomass was demonstrated. Although the hybrid process can significantly enhance nutrient removal and biomass production, further research is needed to intensify the microalgal growth rate. At the current microalgal growth rate, a large MMR volume (37 times that of the MBR) is necessary for synchronous operation.
Fabris, M, Abbriano, RM, Pernice, M, Sutherland, DL, Commault, AS, Hall, CC, Labeeuw, L, McCauley, J, Kuzhiuparambil, U, Ray, P, Kahlke, T & Ralph, PJ 2020, 'Emerging Technologies in Algal Biotechnology: Toward the Establishment of a Sustainable, Algae-Based Bioeconomy', FRONTIERS IN PLANT SCIENCE, vol. 11.View/Download from: Publisher's site
Barolo, L, Abbriano, RM, Commault, AS, George, J, Kahlke, T, Fabris, M, Padula, MP, Lopez, A, Ralph, PJ & Pernice, M 2020, 'Perspectives for Glyco-Engineering of Recombinant Biopharmaceuticals from Microalgae', CELLS, vol. 9, no. 3.View/Download from: Publisher's site
Commault, AS, Fabris, M, Kuzhiumparambil, U, Adriaans, J, Pernice, M & Ralph, PJ 2019, 'Methyl jasmonate treatment affects the regulation of the 2-C-methyl-D-erythritol 4-phosphate pathway and early steps of the triterpenoid biosynthesis in Chlamydomonas reinhardtii', Algal Research, vol. 39.View/Download from: Publisher's site
© 2019 Elsevier B.V. Terpenoids are a large and diverse class of naturally occurring metabolites serving many industrial applications and natural roles. Economically important terpenoids are often produced in low abundance from their natural sources, making their industrial-scale production challenging or uneconomical, therefore engineered microorganisms are frequently used as heterologous production platforms. Photosynthetic microorganisms, such as the green alga Chlamydomonas reinhardtii, represent promising systems to produce terpenoids in a cost-effective and sustainable manner, but knowledge about the regulation of their terpenoid metabolism remains limited. Here we report on the investigation of the phytohormone methyl jasmonate (MeJA) as elicitor of algal terpenoid synthesis. We treated C. reinhardtii cells in mid-exponential growth phase with three different concentrations of MeJA (0.05, 0.5 and 1 mM). The highest concentration of MeJA affected the photosynthetic activity of the cells, arrested the growth and up-regulated key genes of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, leading to a significant increase in intermediates of this pathway, squalene and (S)-2,3-epoxysqualene, while the abundance of cycloartenol, and two main sterols (ergosterol and 7-dehydroporiferasterol) decreased. These data suggest the redirection of the carbon flux towards the synthesis of yet uncharacterised triterpenoid secondary metabolites upon MeJA treatment. Our results offer important new insights into the regulation of the triterpenoid metabolism in C. reinhardtii and raise important questions on hormonal signalling in microalgae. Phytohormone treatment is tested for the first time in algae, where it holds great potential for identifying key transcriptional regulators of the MEP pathway as targets for future metabolic engineering studies for improve production of high-value triterpenoids.
Nguyen, LN, Commault, AS, Johir, MAH, Bustamante, H, Aurisch, R, Lowrie, R & Nghiem, LD 2019, 'Application of a novel molecular technique to characterise the effect of settling on microbial community composition of activated sludge.', Journal of environmental management, vol. 251.View/Download from: Publisher's site
Activated sludge (AS) and return activated sludge (RAS) microbial communities from three full-scale municipal wastewater treatment plants (denoted plant A, B and C) were compared to assess the impact of sludge settling (i.e. gravity thickening in the clarifier) and profile microorganisms responsible for nutrient removal and reactor foaming. The results show that all three plants were dominated with microbes in the phyla of Proteobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria, Chloroflexi, Firmicutes, Nitrospirae, Spirochaetae, Acidobacteria and Saccharibacteria. AS and RAS shared above 80% similarity in the microbial community composition, indicating that sludge thickening does not significantly alter the microbial composition. Autotrophic and heterotrophic nitrifiers were present in the AS. However, the abundance of autotrophic nitrifiers was significantly lower than that of the heterotrophic nitrifiers. Thus, ammonium removal at these plants was achieved mostly by heterotrophic nitrification. Microbes that can cause foaming were at 3.2% abundance, and this result is well corroborated with occasional aerobic biological reactor foaming. By contrast, these microbes were not abundant (<2.1%) at plant A and C, where aerobic biological reactor foaming has not been reported.
Nguyen, LN, Johir, MAH, Commault, A, Bustamante, H, Aurisch, R, Lowrie, R & Nghiem, LD 2019, 'Impacts of mixing on foaming, methane production, stratification and microbial community in full-scale anaerobic co-digestion process.', Bioresource technology, vol. 281, pp. 226-233.View/Download from: Publisher's site
This study investigated the impact of mixing on key factors including foaming, substrate stratification, methane production and microbial community in three full scale anaerobic digesters. Digester foaming was observed at one plant that co-digested sewage sludge and food waste, and was operated without mixing. The lack of mixing led to uneven distribution of total chemical oxygen demand (tCOD) and volatile solid (VS) as well as methane production within the digester. 16S rRNA gene-based community analysis clearly differentiated the microbial community from the top and bottom. By contrast, foaming and substrate stratification were not observed at the other two plants with internal circulation mixing. The abundance of methanogens (Methanomicrobia) at the top was about four times higher than at the bottom, correlating to much higher methane production from the top verified by ex-situ biomethane assay, causing foaming. This result is consistent with foaming potential assessment of digestate samples from the digester.
Nguyen, LN, Labeeuw, L, Commault, AS, Emmerton, B, Ralph, PJ, Johir, MAH, Guo, W, Ngo, HH & Nghiem, LD 2019, 'Validation of a cationic polyacrylamide flocculant for the harvesting fresh and seawater microalgal biomass', Environmental Technology and Innovation, vol. 16.View/Download from: Publisher's site
© 2019 Elsevier B.V. A simple, efficient, and fast settling flocculation technique to harvest microalgal biomass was demonstrated using a proprietary cationic polyacrylamide flocculant for a freshwater (Chlorella vulgaris) and a marine (Phaeodactylum tricornutum) microalgal culture at their mid-stationary growth phase. The optimal flocculant doses were 18.9 and 13.7 mg/g of dry algal biomass for C. vulgaris and P. tricornutum, respectively (equivalent to 7 g per m3 of algal culture for both species). The obtained optimal dose was well corroborated with changes in cell surface charge, and culture solution optical density and turbidity. At the optimal dose, charge neutralization of 64 and 86% was observed for C. vulgaris and P. tricornutum algal cells, respectively. Algae recovery was independent of the culture solution pH in the range of pH 6 to 9. Algal biomass recovery was achieved of 100 and 90% for C vulgaris and P. tricornutum respectively, and over 98% medium recovery was achievable by simple decanting.
Commault, AS, Laczka, O, Siboni, N, Tamburic, B, Crosswell, JR, Seymour, JR & Ralph, PJ 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: 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.
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: Publisher's site
Tran, N-AT, Padula, MP, Evenhuis, CR, Commault, AS, Ralph, PJ & Tamburic, B 2016, 'Proteomic and biophysical analyses reveal a metabolic shift in nitrogen deprived Nannochloropsis oculata', ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS, vol. 19, pp. 1-11.View/Download from: Publisher's site
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: 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.
Commault, AS, Barrière, F, Lapinsonnière, L, Lear, G, Bouvier, S & Weld, RJ 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: 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, AS, Lear, G & Weld, RJ 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: 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 mW·m− 2 (against 74 ± 14 mW·m− 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 g·L− 1 removed against the initial 1.3 g·L− 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, AS, Lear, G & Weld, RJ 2014, 'Comment on microbial community composition is unaffected by anode potential', Environmental science & technology, vol. 48, pp. 14851-14852.
Commault, AS, Lear, G, Novis, P & Weld, RJ 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: 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, AS, Lear, G, Packer, MA & Weld, RJ 2013, 'Influence of anode potentials on selection of Geobacter strains in microbial electrolysis cells', Bioresource Technology, vol. 139, pp. 226-234.View/Download from: 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 m−2 (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 & Weld, RJ 2016, 'Whole-cell Biosensors for Monitoring Bioremediation' in Lear, G (ed), Biofilms in Bioremediation, Caister Academic Press, Norfolk, United Kingdom, pp. 75-91.
Commault, A 2014, 'Engineering microbial fuel cell biofilm communities'.