title: Influence of dissolved oxygen levels on production of L-asparaginase and prodigiosin by Serratia marcescens.
abstract: The effect of dissolved oxygen concentrations on the behavior of Serratia marcescens and on yields of asparaginase and prodigiosin produced in shaken cultures and in a 55-liter stainless-steel fermentor was studied. A range of oxygen transfer rates was obtained in 500-ml Erlenmeyer flasks by using internal, stainless-steel baffles and by varying the volume of medium per flask, and in the fermentor by high speed agitation (375 rev/min) or low rates of aeration (1.5 volumes of air per volume of broth per min), or both. Dissolved oxygen levels in the fermentation medium were measured with a membrane-type electrode. Peak yields of asparaginase were obtained in unbaffled flasks (3.0 to 3.8 IU/ml) and in the fermentor (2.7 IU/ml) when the level of dissolved oxygen in the culture medium reached zero. A low rate of oxygen transfer was accomplished by limited aeration. Production of prodigiosin required a supply of dissolved oxygen that was obtainable in baffled flasks with a high rate of oxygen transfer and in the fermentor with a combination of high-speed agitation and low-rate aeration. The fermentation proceeded at a more rapid rate and changes in pH and cell populations were accelerated by maintaining high levels of dissolved oxygen in the growth medium.
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001215:Asparaginase / Q000096:biosynthesis*; D001431:Bacteriological Techniques; D003124:Colorimetry; D003470:Culture Media; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D010100:Oxygen; D012706:Serratia marcescens / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D001215:Asparaginase; D010100:Oxygen