Abstract

   Thermophiles and psychrophiles, adapted to extreme temperatures, thrive
   in hot and cold environments, respectively. Despite their importance to
   biotechnology and environmental research, their adaptation mechanisms
   remain unclear. We have performed a comparative analysis of the genomes
   and metabolic networks of these species. Psychrophiles were found to
   have larger genomes, more genes, bigger metabolic networks, fewer
   metabolite exchanges, and higher growth rates compared to thermophiles.
   These species show amino acid and codon preferences: thermophiles favor