DEVELOPMENT OF DEFINED AND MINIMAL MEDIA FOR THE GROWTH OF THE HYPERTHERMOPHILIC ARCHAEON PYROCOCCUS-FURIOSUS VC1

The nutritional requirements of Pyrococcus furiosus were determined us ing extended continuous culture in the absence of elemental sulfur in an anaerobic gaslift bioreactor. Replacement of complex nutrients by m altose, amino acids and vitamins alone supported growth. When the orga nic components of this defined medium were optimised, equilibrium cell densities of 10(10) ml(-1) were achieved. Selective feeding and withd rawal revealed requirements for L-proline, L-cysteine and D-biotin. Re placement of maltose by dextrin allowed growth in closed bottles on bo th the defined and minimal media, again in the absence of elemental su lfur. A simple procedure for the efficient plating of P. furiosus on s olid media was also developed.