Carboxylesterase from Sulfolobus solfataricus P1

To date, relatively few investigations regarding the purification and characterization of thermostable (Topt > 60 °) esterases have been conducted. Thus far, esterases from Bacillus acidocaldarius, Pyrococcus furiosus, Bacillus stearothermophilus, Sulfolobus shibatae, Thermoanaerobacterium sp, Pyrococcus abyssi, and Sulfolobus acidocaldarius have been studied to varying extents. Those thermostable esterases that have been evaluated vary significantly with respect to molecular mass, although their biochemical properties, such as pH optimum and substrate specificity, are quite similar. This chapter describes the cloning, expression, purification, and characterization of a recombinant carboxylesterase (Sso P1 carboxylesterase) from the extreme thermoacidophile Sulfolobus solfataricus P1. S. solfataricus, which is a member of the Crenarchaeota, can be found in sulfurous caldrons and volcanic muds.