Kreisel was a professor at the University of Greifswald. His field is the classification of fungi, where he has studied this group of organisms not only in Germany but in almost all continents, as in Brazil, Seychelles, Vietnam, Cuba and Syria. He has succeeded with his first collaboration to develop a scientifically sound and current fungal flora of Yemen. Kreisel also specializes in the fungal groups of gut fungi.
Kreisel was also the editor of several international scientific journals.
- Chrysosporium kreiselii Dominik 1965
- Kreiseliella Braun 1991
- Kreiseliella typhae (Vasyag.) U. Braun 1991
- Meliola kreiseliana Schmied. 1989
- Passalora kreiseliana U. Braun & Crous 2002
- Peziza kreiselii G. Hirsch 1992
- Puccinia kreiselii M. Scholler 1996
- Tulostoma kreiselii G. Moreno, E. Horak & Altés 2002