title: Thermal adaptability of Kluyveromyces marxianus in recombinant protein production.
abstract: BACKGROUND
  Kluyveromyces marxianus combines the ease of genetic manipulation and fermentation with the ability to efficiently secrete high molecular weight proteins, performing eukaryotic post-translational modifications. It is able to grow efficiently in a wide range of temperatures. The secretion performances were analyzed in the host K. marxianus L3 in the range between 5°C and 40°C by means of 3 different reporter proteins, since temperature appears a key parameter for production and secretion of recombinant proteins.
  
  
  RESULTS
  The recombinant strains were able to grow up to 40°C and, along the tested temperature interval (5-40°C), the specific growth rates (μ) were generally lower as compared to those of the untransformed strain. Biomass yields were slightly affected by temperature, with the highest values reached at 15°C and 30°C. The secretion of the endogenous β-fructofuranosidase, used as an internal control, was efficient in the range of the tested temperature, as evaluated by assaying the enzyme activity in the culture supernatants. The endogenous β-fructofuranosidase production was temperature dependent, with the highest yield at 30°C. The heterologous proteins HSA, GAA and Sod1p were all successfully produced and secreted between 5°C and 40°C, albeit each one presented a different optimal production temperature (15, 40, 5-30°C for HSA, GAA and Sod1p, respectively).
  
  
  CONCLUSIONS
  K. marxianus L3 has been identified as a promising and flexible cell factory. In a sole host, the optimization of growth temperatures for the efficient secretion of each individual protein can be carried out over a wide range of temperatures.
authors.affiliation: Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Raimondi
authors.forename: Elena
authors.initials: E
authors.lastname: Zanni
authors.forename: Alberto
authors.initials: A
authors.lastname: Amaretti
authors.forename: Claudio
authors.initials: C
authors.lastname: Palleschi
authors.forename: Daniela
authors.initials: D
authors.lastname: Uccelletti
authors.forename: Maddalena
authors.initials: M
authors.lastname: Rossi
mesh_terms: D018533:Biomass; D005087:Glucan 1,4-alpha-Glucosidase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007716:Kluyveromyces / Q000254:growth & development / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics; D012709:Serum Albumin / Q000235:genetics / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D013696:Temperature; D043324:beta-Fructofuranosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; C000606290:SOD1 protein, human; D012709:Serum Albumin; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D043324:beta-Fructofuranosidase; D005087:Glucan 1,4-alpha-Glucosidase