Associate Professor Suhelen Egan

Associate Professor Suhelen Egan


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 microorgansims 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
      • ARC Discovery Grant 2019-2021, Probiotics for the Ocean Thomas, Egan and Dittami

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.

  • 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).

  • 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.

Supervision Opportunities/Areas

Advice for prospective students

Much of what we do is in collaboration with other scientist both at UNSW and elsewhere giving 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.




Courses I teach

Professional affiliations and service positions




02 9385 8569

Room 501B, Level 5 East, Biological Sciences North (D26), UNSW, Kensington 2052