title: Large-scale cultivation of acidophilic hyperthermophiles for recovery of secreted proteins.
abstract: An electric water heater was modified for large-scale cultivation of aerobic acidophilic hyperthermophiles to enable recovery of secreted proteins. Critical changes included thermostat replacement, redesign of the temperature control circuit, and removal of the cathodic anticorrosion system. These alterations provided accurate temperature and pH control. The bioreactor was used to cultivate selected strains of the archaeon Sulfolobus solfataricus and other species within this genus. Reformulation of a basal salts medium facilitated preparation of large culture volumes and eliminated sterilization-induced precipitation of medium components. Substrate induction of synthesis of the S. solfataricus-secreted alpha-amylase during growth in a defined medium supported the utility of the bioreactor for studies of physiologically regulated processes. An improved purification strategy was developed by using strong cation-exchange chromatography for recovery of the alpha-amylase and the processing of large sample volumes of acidic culture supernatant. These findings should simplify efforts to study acidophilic hyperthermophilic microbes and their secreted proteins.
authors.affiliation: School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: Penny
authors.initials: P
authors.lastname: Worthington
authors.forename: Paul
authors.initials: P
authors.lastname: Blum
authors.forename: Francisco
authors.initials: F
authors.lastname: Perez-Pomares
authors.forename: Tom
authors.initials: T
authors.lastname: Elthon
mesh_terms: D019843:Archaeal Proteins / Q000378:metabolism*; D019149:Bioreactors; D003470:Culture Media; D019848:Gene Expression Regulation, Archaeal; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D016944:Sulfolobus / Q000254:growth & development* / Q000378:metabolism; D000516:alpha-Amylases / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins; D003470:Culture Media; D000516:alpha-Amylases