Microbiologist Karl-Otto Stetter

“I didn’t want a secret curiosity shop“

Karl-Otto Stetter is recognized as a pioneer in the study of primeval life. His unabated desire to explore led him to the most remote regions in the world. Whether it is about rare and novel microbes or exotic orchids, the TUM Alumni is always sharing his findings with the world.

Professor Dr. Karl-Otto Stetter was interested in microbes from an early age on. Using a small microscope that his parents gave him as a Christmas present, he explored these tiny organisms. And they continued to intrigue the Munich-born scientist for the rest of his life. “My passion is the cultivation of novel living organisms”, he says. “The fact that this is usually a difficult task spurs me on even more.”

A Wide Range of Interests

Given his interest in technology and biology, Karl-Otto Stetter studied Mechanical Engineering and Biology at TUM. Here, TUM Professor Dr. Otto Kandler nurtured his enthusiasm for Biology and Microbiology and became his mentor for many years. Under his guidance, Karl-Otto Stetter completed his diploma and doctorate.

Karl-Otto Stetter found studying at TUM “exhausting in a positive way”. The wide and varied array of different courses and internships presented a real challenge for the student who had multifaceted interests. But it was worth it. “At TUM I acquired a very broad spectrum of knowledge,” he says. “In my later research work I have benefitted from it countless times.”

Unabated Desire to Explore

Karl-Otto Stetter’s lifelong field of research were so-called extremophiles. With great dedication he sampled, isolated, cultivated and classified these microorganisms, which have been living for millions of years under extreme conditions generally considered hostile to life. In the course of evolution, they managed to adapt to particularly low or high temperatures, to withstand high pressure or high saline levels, or even to survive without oxygen.

Extremophile organisms live in the deep sea, hydrothermal vents, volcanoes and glaciers. And Karl-Otto Stetter travelled to all these habitats. “On my travels, I visited areas which had hardly been exposed to people at all”, he says. “Sampling was so important to me that I always did it myself.” These samples allowed Karl-Otto Stetter later on to be able to successfully cultivate microorganisms in intensive and time-consuming laboratory work.

At TUM I acquired a very broad spectrum of knowledge. In my research work I have benefitted from it countless times.

At a depth of over 4000 meters Karl-Otto Stetter took samples from Black Smokers, the hydrothermal vents on the Mid Atlantic Ridge. He climbed to the summit of the 3800 meter high, active volcano Mount Erebus in Antarctica and conducted research on an oil platform in the North Sea. During his dives to the bottom of the more than 100 meter deep Lake Toplitz in Styria, he studied anaerobic microbial life in the cold of a mountain lake.

Curious Findings

Karl-Otto Stetter made groundbreaking contributions to understanding the origins of life with his research on microorganisms, especially on Archaea. “My curiosity to discover and research new forms of life spurred me on”, he explains. “The exciting, often completely unexpected results obtained in the process continued to encourage me, so that I always gave it my all.”

Through his joint research with Wolfram Zillig, Karl-Otto Stetter was able to confirm Carl Woese’s revolutionary postulate of Archaea as the third domain of life. He himself has also discovered unknown primeval creatures: In a submarine hydrothermal region off Sicily, he discovered Pyrodictium, for example, which grow at temperatures of up to 110°C. In hydrothermal vents off Iceland’s coast, he discovered Nanoarchaeum equitans (the riding primeval dwarf) which has the smallest known genome. This heat-resistant microbe is only 400 nanometers in size and lives on the surface of another Archaeon.

“Due to the special and novel nature of the microbes I found, I collaborated and exchanged ideas with numerous researchers all around the world, who studied my findings from a variety of angles”, Karl-Otto Stetter explains. “After all, I didn’t want to just own a secret curiosity shop.” To this day, this attitude has not changed. Instead of microorganisms, Karl-Otto Stetter now cultivates rare orchids. Visitors are always welcome. In the year 2020, BR Television has been a frequent guest.