title: Fermentative production of superoxide dismutase with Kluyveromyces marxianus.
abstract: This work sought to develop a fermentative process for the microbial production of superoxide dismutase (SOD), to overcome extraction from animal tissues. Twenty-eight wild-type yeast strains were screened for SOD productivity. Kluyveromyces marxianus L3 showed the highest SOD activity (62 U mg(-1)) and was used for process development. Oxidative stress conditions and parameters affecting oxygen transfer rate were exploited to improve production. The effects of dilution rate (0.067 vs 0.2 h(-1)), aeration pressure (0.3 vs 1.2 bar) and H(2)O(2) (0 vs 50 mM) were studied during chemostat experiments. Low dilution rate, high pressure and H(2)O(2) resulted in an increase in CuZn-SOD up to 475 U mg(-1). When a regulation of oxygen saturation was applied during batch cultures, CuZn-SOD was progressively higher at 60, 80 and 90% dissolved oxygen tension (DOT) (250, 330 and 630 U mg(-1), respectively). Furthermore, the highest growth rate and biomass yield were achieved at 90% DOT, this being therefore the best DOT condition for high overall productivity. Growth and productivity on different carbon sources were compared. Specific activity was higher on glycerol than on lactose or glucose (496, 454 and 341 U mg(-1), respectively). The highest biomass yield was achieved on lactose. It may be therefore the best substrate for SOD production.
authors.affiliation: Department of Pharmaceutical Sciences, University of Bologna, Bologna, Italy.
authors.forename: Clementina
authors.initials: C
authors.lastname: Dellomonaco
authors.forename: Alberto
authors.initials: A
authors.lastname: Amaretti
authors.forename: Simona
authors.initials: S
authors.lastname: Zanoni
authors.forename: Anna
authors.initials: A
authors.lastname: Pompei
authors.forename: Diego
authors.initials: D
authors.lastname: Matteuzzi
authors.forename: Maddalena
authors.initials: M
authors.lastname: Rossi
mesh_terms: D001709:Biotechnology / Q000379:methods*; D018929:Cell Culture Techniques; D003470:Culture Media / Q000494:pharmacology; D005285:Fermentation; D007218:Industrial Microbiology / Q000379:methods*; D007716:Kluyveromyces / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development*; D007785:Lactose / Q000494:pharmacology; D018384:Oxidative Stress; D010100:Oxygen / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000096:biosynthesis*
chemical_list: D003470:Culture Media; D013482:Superoxide Dismutase; D007785:Lactose; D010100:Oxygen