John E. Hallsworth

Lecturer of Environmental Microbiology, Queen's University Belfast

John E. Hallsworth is a microbiologist who studies biophysical constraints on microbial systems from their cells to the level of biosphere, and the ways in which biology can circumvent these.

He was born in Lancashire (England); graduated Plant Science from University of London (BSc. Hons, 1990); worked for a year in a pesticide research group (Dow Chemicals Inc., Oxfordshire), completed a PhD in Fungal Stress Metabolism at Cranfield University (1995); and held research positions in Edinburgh (Scotland), Japan and South Africa where he focused on elucidating stress mechanisms and responses in yeasts and fungi. During two further research positions, at University of Essex (England), he then focused on stress in bacterial and archaea systems, including halophilic species.

He has been a member of Faculty at Queen's University Belfast (Northern Ireland) from 2005 to present, during which time he has made research frequent visits to work with collaborators in India, Japan, Brazil, USA, and various European countries.

John's work has shown that microbes can proliferate at lower water activities than recognised previously; both halophilic bacteria and archaea and fungi that grow at high sugar, high salt, or under dry conditions.

He showed that chaotropicity causes stress in microbial cells; that microbes respond to this stress at all levels (from gene to cellular phenotype); chaotropic substances enable microbial activity at lower temperatures; that chaotropicity also limits life in some environments on Earth; and devised a technique to quantify this parameter.

In recent years he has become recognised in the biotechnology and astrobiology fields. His findings have enhanced biological control of agricultural pests using insect-pathogenic fungi, and can be used to optimise production of alcohol as a biofuel. He has also sat on a number of expert panels for NASA, European Space Agency, Committee for Space Research (COSPAR) and the EU's European Research Agency in relation to applications such as techniques for life detection and international policy on planetary protection.

John has published 70 research papers, in Nature, PNAS, Astrobiology, Microbial Biotechnology, Environmental Microbiology and other journals. Some of his studies provide novel insights by using reductionist datasets to understand holistic aspects of microbial ecology ( and stress biology ( From a plant science background, followed by more than 25 years' work in the microbiology field, his interests have come full circle and he recently begun to work on biophysical constraints and responses of some plant systems.

Within his research group, John enjoys interactions with PhD students and tried to motivate them to publish findings in a way accessible to a wide scientific readership ( and A number of his undergraduate students have also published (first-author) papers on seminal aspects of microbial stress biology and astrobiology ( and

At home, he enjoys playing with his 8-year-old daughter and 5-year-old son, and introducing them to the joys of the natural world.


  • –present
    Lecturer of Molecular Biosciences, Queen's University Belfast