Karl O. Stetter PhD

Karl Otto Stetter (born July 16, 1941) is a German microbiologist and astrobiologist, an expert on microbial life at the upper temperature, and one of the most important scientists currently working in this field. Stetter was born in Munich and studied biology at the Technische Universität Munich. He wrote his doctoral dissertation on lactobacilli. From 1980 to 2002 he was a professor at, and head of, the department of microbiology and of the Archaea center of the Universität Regensburg.

The majority of Professor Stetter's research has focused on sampling, isolating, and characterizing archaeal organisms which comprise the third domain of life, particularly undiscovered extremely heat-loving (hyperthermophilic) bacteria, and Archaea, also called extremophiles, growing optimally between 80 and 113°C. Recently, he has worked extensively on the organism Nanoarchaeum equitans, an archaeal microorganism containing the world's smallest known genome. This archaebacterium is one of his important discoveries, which was described in the scientific journal Nature in May 2002.