A journey of scientific discovery

After leaving Brisbane Girls Grammar in 1948, Cathryn initially pursued a career in healthcare, working as a Dental Assistant at the University of Queensland's College of Dentistry in Turbot Street, before enrolling in a nursing and midwifery program at Brisbane Hospital.

Recognised for her exceptional skills, Cathryn was appointed as a tutor when the Princess Alexandra Hospital opened a nursing school. This sparked an interest in teaching, and she completed a Diploma of Nursing Education.

Inspired to study further, Cathryn enrolled in a Bachelor of Science at the University of Queensland in 1963, a move that unexpectedly shifted her focus from people to plants.

At UQ, Cathryn found she loved and excelled in botany, finishing her degree with first class honours in 1968 and earning a University Medal. She went on to complete a PhD in 1971. During her doctoral research Cathryn discovered a substance that helps plants retain water and became one of the first Australians to be published in renowned international journal Nature. The article garnered global attention and is still cited in academic papers.

After graduating, Cathryn was awarded a CSIRO post-doctoral fellowship at UQ, then worked as `Acting Lecturer' in plant cell physiology. Permanent lecturing positions were not open to females—even ones with a PhD and University Medal to their name.

‘Tenured lecturer positions in the Faculty of Science were unheard of for women in those days,' Cathryn remembers. When her mother fell ill in 1976, she stepped away from academic life to care for her until she passed away shortly after.

In the late 1970s, Cathryn, and her sister Margaret, who both retained a passionate curiosity and sense of adventure, threw themselves into exploring the globe as the world started to open to international travel.

They visited China after the 1978 `open door' policy welcomed Western tourists, and the sisters joined two expeditions to Antarctica in the 1990s, with Cathryn becoming somewhat of an expert on the then little-known continent.

Together, the Mittelheuser sisters are luminaries in both academic and philanthropic circles. Both were outstanding in their respective fields, with Margaret becoming the first female stockbroker in Australia and a leading practitioner until her retirement from ABN Amro Morgans in 2006. They spent their later years focused on philanthropy, supporting the arts and education, in particular.

In 1985, Cathryn was elected President of the Brisbane Lyceum Club, an organisation established to support women in the arts, literature, music, science, education, journalism, and current affairs

`If you can help someone else, well, why not?' Cathryn said. `There's so much pleasure in it.'

In the 1990s, in what is thought to be a first for any Australian university, both sisters were separately awarded honorary Doctor of Philosophy degrees for their contributions to the University of Queensland, their fields of study, and the wider community.

The decade also marked the sisters being appointed to the Order of Australia—Margaret in 1996 and Cathryn in 1999. In 2021, both sisters were jointly named Queensland Greats, an award recognising outstanding Queenslanders, and had their names added to an honour wall in Roma Street Parkland.

The Mittelheusers' exceptional generosity to Brisbane Girls Grammar School has played a key role in the improvement of facilities and the creation of programs to enrich student learning. The sisters initiated the Artist in Residence program and were the founding patrons of the School's Bequest Programme.

In recognition of their contributions, the Physics and Chemistry Departments within the Science Learning Centre are named in their honour.

In 2006, the Mittelheuser sisters were founding donors of the landmark Cherrell Hirst Creative Learning Centre. And in 2008, the School established the Margaret and Cathryn Mittelheuser Museum, which honours BGGS's leading alumnae and continues their commitment to the education of girls and the preservation of culture.

After a long and celebrated career, Margaret passed away in December, 2013, after being cared for in her final months by her beloved sister.

Cathryn's ongoing journey is a testament to the power of following one’s passions and embracing personal and professional reinvention. Her life reflects the ethos that joy lies not only in the destination but in the experiences and discoveries along the way.