Dr Suhelen Egan
ARC Future Fellow and Deputy Director
Field of Research: 
Microbiology, Microbial Ecology, Environmental Biotechnology, Biological Sciences
Contact details:
+61 2 9385 8569

Room 263A, Biological Sciences D26-link-wing
UNSW, Kensington 2052



I have a broad interest in the areas of environmental microbiology, marine ecology and biotechnology. My recent work in these areas aims to gain a better understanding of the interactions between marine microorganims and their eukaryotic hosts from both an ecological and cellular/mechanistic perspective. The study of seaweed associated microbial communities using molecular, genomic and classical tools has lead to the discovery of new bacterial species, the identification of novel antimicrobials and to a greater understanding of the traits important for host-associated life.


  • Graduate certificate in University Learning and Teaching, UNSW Australia, 2009
  • PhD in Microbiology, UNSW Australia, 2001
  • BSc (Honours Class 1) majoring in Microbiology and Immunology, UNSW Australia, 1995




Research Goals

  • To gain a broader understanding of the depth of microbial diversity and how microorganism shape temperate marine ecosystems
  • To study the molecular mechanism that drive symbiotic interactions between microorganisms and the marine eukaryotic host
  • To understand the ecological role of bioactive metabolites such as antibiotics
  • To elucidate the role of microbial pathogens in emerging seaweed disease
  • To discover new antimicrobial compounds from marine bacteria

Research in Detail

For a long time I have been interested in using microbiology to prevent marine biofouling and for the discovery of new biologically active metabolites. This research has lead to the characterisation of new compounds with a wide range of targeted activities (including anti-bacterial, anti-fungal, anti-algal and anti-nematode).

In particular our work with the antifouling bacterium Pseudoalteromonas tunicata, which spans molecular biology, genomics, proteomics, ecology and natural product chemistry has enabled this strain to be recognised as a model organisms in the field of marine microbiology. An additional outcome of these studies has been the detection of genes involved in environmental stress and potentially virulence. These discoveries have contributed to the hypothesis that in natural systems opportunistic pathogens may play a role in disease of marine seaweeds.

Despite the growing interest in marine microbial ecology there is still much to learn about the diversity of host-associated microbial communities and the functional role of their members. Studies such as these are important on a number of levels. For example understanding the diversity and function of eukaryotic associated microbes can add to our understanding of disease, provide insight to the rich global biodiversity and lead to the discovery of new and improved processes and products

Research Grants

  • ARC Future Fellowship Grant 2014-2018 .Chemical warfare in the marine environment: role of surface associated bacteria and their antibiotics
  • ARC Discovery Grant 2010-2013, Stress, Virulence and Bacterial Disease in Temperate Seaweeds: The rise of the Microbes CI’s Steinberg, Kjelleberg, Thomas, Egan and Coleman
  • ARC Linkage Grant 2006-2010 Environmental genomics and novel bioactives from microbial communities on living marine surfaces CI’s Kjelleberg, Steinberg, Thomas, Egan, Holmström, Venter, Heidelberg, Sutton, Rusch and Halpern

Current Student Projects (PhD and Honours)

  • Discovery of novel bioactive compounds from marine host-associated bacteria. 

The bacterial symbionts of marine eukaryotes (seaweeds, sponges, corals etc) are proving to be an excellent, yet understudied, source of new metabolites that hold potential as next generation antibiotics. This project uses both traditional culturing and modern culture-independent (functional metagenomics) methods to discover new biologically active metabolites from bacteria and the genes involved in their production. Students on this project have the opportunity to learn a range of skills including antimicrobial bioassays (against nematode, fungal and/or bacterial targets), molecular biology (e.g. PCR, DNA sequencing, cloning) and natural product chemistry (e.g. chemical extraction and separation technologies) methods. Current students working in this area include Jadranka Nappi (PhD student) and Carolina Campi (International Masters Student). Collaborators on this project include Dr John Kalaitzis (BABS) and Dr Tilmann Harder (CMB).

  • Deciphering the mechanism of microbial disease progression in marine habitat-forming macroalgae.

It is proposed that with increases in anthropogenic stressors of coastal systems (pollution/ climate change) there comes an increase in the prevalence of disease caused by opportunistic pathogens. Here we are using genomic and gene expression analysis together with site-directed mutagenesis to identify and characterise potential virulence mechanisms in model macroalgal disease systems. We also perform environmental surveys to assessing prevalence of pathogens and determine how the natural microbial community shifts under disease conditions. Current people working in this area include Vipra Kumar (PhD Student), Melissa Gardiner (former PhD student and Research staff member). This project is in collaboration with A/Prof. Torsten Thomas (BABS/CMB) and Prof. Peter Steinberg (BEES/ CMB).

  • The ecological role of antibiotic producing bacteria.

Antibiotics from natural sources are an essential part of modern medicine, however their function in the environment is poorly understood. In this project we perform manipulation experiments (both at UNSW and at Sydney Institute for Marine Science (SIMS)) combined with a range of –omic technologies (e.g. deep sequencing of phylogenetic marker genes, genomics, transcriptomics etc) to define how antibiotic-producing bacteria from marine macroalgae determine ecological interactions. This project addresses the fundamental question of the impact of antibiotics in natural systems and the role of antibiotic-producing bacteria in safeguarding important habitat-forming macroalgae against environmental stress. Current students on this project include Marwan Majzoub (PhD student), Jadranka Nappi (PhD student) and An Grobler (Hons Student).

Advice for prospective students

Much of what we do is in collaboration with other scientist both at UNSW and elsewhere. Whilst our lab is housed in the School of Biotechnology and Biomolecular Sciences (BABS) we also work closely with academics in the School of Biological, Earth and Environmental Science (BEES) and in the Centre for Marine Bio-Innovation (CMB), which gives students the opportunity to interact with and gain experience from a diverse group of scientist.

We encourage students at all levels of their study including undergraduate internships, honours, MPhil, International practicums, Masters and PhD programs to fully participate in the group. So, if you are interested to learn more about what we do, or have some idea’s of your own that you would like to share please do not hesitate to call in or pop me an email.


Journal articles

Egan S;Gardiner M, 2016, 'Microbial Dysbiosis: Rethinking Disease in Marine Ecosystems.', Front Microbiol, vol. 7, pp. 991, http://dx.doi.org/10.3389/fmicb.2016.00991

Ballestriero F;Nappi J;Zampi G;Bazzicalupo P;Di Schiavi E;Egan S, 2016, 'Caenorhabditis elegans employs innate and learned aversion in response to bacterial toxic metabolites tambjamine and violacein', Scientific Reports, vol. 6, http://dx.doi.org/10.1038/srep29284

Kumar V;Zozaya-Valdes E;Kjelleberg S;Thomas T;Egan S, 2016, 'Multiple opportunistic pathogens can cause a bleaching disease in the red seaweed Delisea pulchra', Environmental Microbiology, vol. 18, pp. 3962 - 3975, http://dx.doi.org/10.1111/1462-2920.13403

Mazard S;Penesyan A;Ostrowski M;Paulsen IT;Egan S, 2016, 'Tiny microbes with a big impact: The role of cyanobacteria and their metabolites in shaping our future', Marine Drugs, vol. 14, http://dx.doi.org/10.3390/md14050097

Lutz C;Thomas T;Steinberg P;Kjelleberg S;Egan S, 2016, 'Effect of interspecific competition on trait variation in Phaeobacter inhibens biofilms', Environmental Microbiology, vol. 18, pp. 1635 - 1645, http://dx.doi.org/10.1111/1462-2920.13253

Gardiner M;Fernandes ND;Nowakowski D;Raftery M;Kjelleberg S;Zhong L;Thomas T;Egan S, 2015, 'VarR controls colonization and virulence in the marine macroalgal pathogen Nautella italica R11', Frontiers in Microbiology, vol. 6, http://dx.doi.org/10.3389/fmicb.2015.01130

Gardiner M;Thomas T;Egan S, 2015, 'A glutathione peroxidase (GpoA) plays a role in the pathogenicity of Nautella italica strain R11 towards the red alga Delisea pulchra', FEMS Microbiology Ecology, vol. 91, http://dx.doi.org/10.1093/femsec/fiv021

Egan S;Thomas T, 2015, 'Editorial for: Microbial symbiosis of marine sessile hosts- diversity and function', Frontiers in Microbiology, vol. 6, http://dx.doi.org/10.3389/fmicb.2015.00585

Zozaya-Valdes E; Egan S; Thomas T, 2015, 'A comprehensive analysis of the microbial communities of healthy and diseased marine macroalgae and the detection of known and potential bacterial pathogens.', Frontiers in Microbiology, vol. 6, pp. 146, http://dx.doi.org/10.3389/fmicb.2015.00146

Ballestriero F; Daim M; Penesyan A; Nappi J; Schleheck D; Bazzicalupo P; Di Schiavi E; Egan S, 2014, 'Antinematode activity of Violacein and the role of the insulin/IGF-1 pathway in controlling violacein sensitivity in Caenorhabditis elegans.', PLoS One, vol. 9, no. 10, pp. e109201, http://dx.doi.org/10.1371/journal.pone.0109201

Gardiner M; Hoke DE; Egan S, 2014, 'An ortholog of the Leptospira interrogans lipoprotein LipL32 aids in the colonization of Pseudoalteromonas tunicata to host surfaces.', Frontiers in Microbiology, vol. 5, pp. 323, http://dx.doi.org/10.3389/fmicb.2014.00323

Egan S; Fernandes ND; Kumar V; Gardiner M; Thomas T, 2014, 'Bacterial pathogens, virulence mechanism and host defence in marine macroalgae.', Environmental Microbiology, vol. 16, no. 4, pp. 925 - 938, http://dx.doi.org/10.1111/1462-2920.12288

Penesyan A; Breider S; Schumann P; Tindall BJ; Egan S; Brinkhoff T, 2013, 'Epibacterium ulvae gen. nov., sp. nov., epibiotic bacteria isolated from the surface of a marine alga.', International Journal of Systematic and Evolutionary Microbiology, vol. 63, no. Pt 5, pp. 1589 - 1596, http://dx.doi.org/10.1099/ijs.0.042838-0

Penesyan A; Ballestriero F; Daim M; Kjelleberg S; Thomas T; Egan S, 2013, 'Assessing the effectiveness of functional genetic screens for the identification of bioactive metabolites.', Marine Drugs, vol. 11, no. 1, pp. 40 - 49, http://dx.doi.org/10.3390/md11010040

Egan S; Penesyan A, 2012, 'Marine bacteria as a source of new antibiotics', , pp. 381 - 412

Hoke DE; Zhang K; Egan S; Hatfaludi T; Buckle AM; Adler B, 2011, 'Membrane proteins of Pseudoalteromonas tunicata during the transition from planktonic to extracellular matrix-adherent state.', Environmental Microbiology Reports, vol. 3, no. 3, pp. 405 - 413, http://dx.doi.org/10.1111/j.1758-2229.2011.00246.x

Thomas T; Rusch D; DeMaere MZ; Yung PY; Lewis M; Halpern A; Heidelberg KB; Egan S; Steinberg PD; Kjelleberg S, 2010, 'Functional genomic signatures of sponge bacteria reveal unique and shared features of symbiosis.', The ISME Journal: multidisciplinary journal of microbial ecology, vol. 4, no. 12, pp. 1557 - 1567, http://dx.doi.org/10.1038/ismej.2010.74

Penesyan A; Kjelleberg S; Egan S, 2010, 'Development of novel drugs from marine surface associated microorganisms.', Marine Drugs, vol. 8, no. 3, pp. 438 - 459, http://dx.doi.org/10.3390/md8030438

Ballestriero F; Thomas T; Burke C; Egan S; Kjelleberg S, 2010, 'Identification of compounds with bioactivity against the nematode Caenorhabditis elegans by a screen based on the functional genomics of the marine bacterium Pseudoalteromonas tunicata D2.', Applied and Environmental Microbiology, vol. 76, no. 17, pp. 5710 - 5717, http://dx.doi.org/10.1128/aem.00695-10

Penesyan A; Kjelleberg S; Egan SG, 2010, 'Development of Novel Drugs from Marine Surface Associated Microorganisms', Marine Drugs, vol. 8, no. 3, pp. 428 - 459

Yung PY; Burke C; Lewis M; Egan S; Kjelleberg S; Thomas T, 2009, 'Phylogenetic screening of a bacterial, metagenomic library using homing endonuclease restriction and marker insertion.', Nucleic Acids Research, vol. 37, no. 21, pp. e144, http://dx.doi.org/10.1093/nar/gkp746

Penesyan A; Marshall-Jones Z; Holmstrom C; Kjelleberg S; Egan S, 2009, 'Antimicrobial activity observed among cultured marine epiphytic bacteria reflects their potential as a source of new drugs.', FEMS Microbiology Ecology, vol. 69, no. 1, pp. 113 - 124, http://dx.doi.org/10.1111/j.1574-6941.2009.00688.x

Lauro FM; McDougald D; Thomas T; Williams TJ; Egan S; Rice S; DeMaere MZ; Ting L; Ertan H; Johnson J; Ferriera S; Lapidus A; Anderson I; Kyrpides N; Munk AC; Detter C; Han CS; Brown MV; Robb FT; Kjelleberg S; Cavicchioli R, 2009, 'The genomic basis of trophic strategy in marine bacteria.', Proceedings of the National Academy of Sciences of USA, vol. 106, no. 37, pp. 15527 - 15533, http://dx.doi.org/10.1073/pnas.0903507106

Thomas T; Evans FF; Schleheck D; Mai-Prochnow A; Burke C; Penesyan A; Dalisay DS; Stelzer-Braid S; Saunders N; Johnson J; Ferriera S; Kjelleberg S; Egan S, 2008, 'Analysis of the Pseudoalteromonas tunicata genome reveals properties of a surface-associated life style in the marine environment.', PLoS One, vol. 3, no. 9, pp. e3252, http://dx.doi.org/10.1371/journal.pone.0003252

Hoke DE; Egan S; Cullen PA; Adler B, 2008, 'LipL32 is an extracellular matrix-interacting protein of Leptospira spp. and Pseudoalteromonas tunicata.', Infection and Immunity, vol. 76, no. 5, pp. 2063 - 2069, http://dx.doi.org/10.1128/iai.01643-07

Matz C; Webb JS; Schupp PJ; Phang SY; Penesyan A; Egan S; Steinberg P; Kjelleberg S, 2008, 'Marine biofilm bacteria evade eukaryotic predation by targeted chemical defense.', PLoS One, vol. 3, no. 7, pp. e2744, http://dx.doi.org/10.1371/journal.pone.0002744

Mai-Prochnow A; Lucas-Elio P; Egan S; Thomas T; Webb JS; Sanchez-Amat A; Kjelleberg S, 2008, 'Hydrogen peroxide linked to lysine oxidase activity facilitates biofilm differentiation and dispersal in several gram-negative bacteria.', Journal of Bacteriology, vol. 190, no. 15, pp. 5493 - 5501, http://dx.doi.org/10.1128/jb.00549-08

Evans FF; Egan S; Kjelleberg S, 2008, 'Ecology of type II secretion in marine gammaproteobacteria.', Environmental Microbiology, vol. 10, no. 5, pp. 1101 - 1107, http://dx.doi.org/10.1111/j.1462-2920.2007.01545.x

Egan S; Thomas T; Kjelleberg S, 2008, 'Unlocking the diversity and biotechnological potential of marine surface associated microbial communities.', Current Opinion in Microbiology, vol. 11, no. 3, pp. 219 - 225, http://dx.doi.org/10.1016/j.mib.2008.04.001

Evans FF; Raftery MJ; Egan S; Kjelleberg S, 2007, 'Profiling the secretome of the marine bacterium Pseudoalteromonas tunicata using amine-specific isobaric tagging (iTRAQ).', Journal of Proteome Research, vol. 6, no. 3, pp. 967 - 975, http://dx.doi.org/10.1021/pr060416x

Burke C; Thomas T; Egan S; Kjelleberg S, 2007, 'The use of functional genomics for the identification of a gene cluster encoding for the biosynthesis of an antifungal tambjamine in the marine bacterium Pseudoalteromonas tunicata.', Environmental Microbiology, vol. 9, no. 3, pp. 814 - 818, http://dx.doi.org/10.1111/j.1462-2920.2006.01177.x

Thomas T; Egan S; Burg D; Ng C; Ting L; Cavicchioli R, 2007, 'Integration of genomics and proteomics into marine microbial ecology', Marine Ecology: Progress Series, vol. 332, pp. 291 - 299, http://dx.doi.org/10.3354/meps332291

Stelzer S; Egan S; Larsen MR; Bartlett DH; Kjelleberg S, 2006, 'Unravelling the role of the ToxR-like transcriptional regulator WmpR in the marine antifouling bacterium Pseudoalteromonas tunicata.', Microbiology, vol. 152, no. Pt 5, pp. 1385 - 1394, http://dx.doi.org/10.1099/mic.0.28740-0

Dalisay DS; Webb JS; Scheffel A; Svenson C; James S; Holmström C; Egan S; Kjelleberg S, 2006, 'A mannose-sensitive haemagglutinin (MSHA)-like pilus promotes attachment of Pseudoalteromonas tunicata cells to the surface of the green alga Ulva australis.', Microbiology, vol. 152, no. Pt 10, pp. 2875 - 2883, http://dx.doi.org/10.1099/mic.0.29158-0

Franks A; Egan S; Holmström C; James S; Lappin-Scott H; Kjelleberg S, 2006, 'Inhibition of fungal colonization by Pseudoalteromonas tunicata provides a competitive advantage during surface colonization.', Applied and Environmental Microbiology, vol. 72, no. 9, pp. 6079 - 6087, http://dx.doi.org/10.1128/aem.00559-06

Franks A; Egan S; Holmström C; James S; Lappin-Scott H; Kjelleberg S, 2006, 'Inhibition of fungal colonization by Pseudoalteromonas tunicata provides a competitive advantage during surface colonization', Applied and Environmental Microbiology, vol. 72, no. 9, pp. 6079 - 6087, http://dx.doi.org/10.1128/AEM.00559-06

Franks A; Haywood P; Holmström C; Egan S; Kjelleberg S; Kumar N, 2005, 'Isolation and structure elucidation of a novel yellow pigment from the marine bacterium Pseudoalteromonas tunicata.', Molecules, vol. 10, no. 10, pp. 1286 - 1291, http://dx.doi.org/10.3390/10101286

Mai-Prochnow A; Evans F; Dalisay-Saludes D; Stelzer S; Egan S; James S; Webb JS; Kjelleberg S, 2004, 'Biofilm development and cell death in the marine bacterium Pseudoalteromonas tunicata.', Applied and Environmental Microbiology, vol. 70, no. 6, pp. 3232 - 3238, http://dx.doi.org/10.1128/aem.70.6.3232-3238.2004

Holmström C; Egan S; Franks A; McCloy S; Kjelleberg S, 2002, 'Antifouling activities expressed by marine surface associated Pseudoalteromonas species.', FEMS Microbiology Ecology, vol. 41, no. 1, pp. 47 - 58, http://dx.doi.org/10.1111/j.1574-6941.2002.tb00965.x

Egan S; James S; Holmström C; Kjelleberg S, 2002, 'Correlation between pigmentation and antifouling compounds produced by Pseudoalteromonas tunicata.', Environmental Microbiology, vol. 4, no. 8, pp. 433 - 442, http://dx.doi.org/10.1046/j.1462-2920.2002.00322.x

Egan S; James S; Kjelleberg S, 2002, 'Identification and characterization of a putative transcriptional regulator controlling the expression of fouling inhibitors in Pseudoalteromonas tunicata.', Applied and Environmental Microbiology, vol. 68, no. 1, pp. 372 - 378, http://dx.doi.org/10.1128/aem.68.1.372-378.2002

Egan S; Holmström C; Kjelleberg S, 2001, 'Pseudoalteromonas ulvae sp. nov., a bacterium with antifouling activities isolated from the surface of a marine alga.', International Journal of Systematic and Evolutionary Microbiology, vol. 51, no. Pt 4, pp. 1499 - 1504

Egan S; James S; Holmström C; Kjelleberg S, 2001, 'Inhibition of algal spore germination by the marine bacterium Pseudoalteromonas tunicata', FEMS Microbiology Ecology, vol. 35, no. 1, pp. 67 - 73, http://dx.doi.org/10.1016/S0168-6496(00)00112-4

Egan S; Thomas T; Holmström C; Kjelleberg S, 2000, 'Phylogenetic relationship and antifouling activity of bacterial epiphytes from the marine alga Ulva lactuca.', Environmental Microbiology, vol. 2, no. 3, pp. 343 - 347, http://dx.doi.org/10.1046/j.1462-2920.2000.00107.x

Holmström C; James S; Egan S; Kjelleberg S, 1996, 'Inhibition of common fouling organisms by marine bacterial isolates ith special reference to the role of pigmented bacteria.', Biofouling: the journal of bioadhesion and biofilm research, vol. 10, no. 1-3, pp. 251 - 259, http://dx.doi.org/10.1080/08927019609386284

Holmstrom CG; James SG; Egan SG; Kjelleberg S, 1996, 'Inhibition of common fouling organisms by pigmented marin bacterial isolates', Biofouling: the journal of bioadhesion and biofilm research, vol. 10, pp. 251 - 259

Conference Papers

Egan S; Holmstrom CG; James SG; Kjelleberg S, 1998, 'Inhibition of various marine organisms by extracellular components produced by Pseudoaltermonas tunicata', in Microbiology Australia, Thomas Business Publishers, Chippendale, NSW, pp. A81 - A81, presented at ASM 1998:Australian Society for Microbiology Annual Scientific Meeting, Hobart, 27 September - 2 October 1998