ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Summary The effects of oxygen (100%), paraquat (0.5 mM), and copper (0.1 mM) on the growth and the biosynthesis of the antioxidant enzymes, superoxide dismutase (SOD) and catalase, were studied in Saccharomyces cerevisiae grown in glucose-limited chemostat cultures. The effect of dilution rates (D, h−1) on cell mass, glucose consumption, ethanol production, oxygen uptake, and specific activities of SOD and catalase were also investigated at each steady state. SOD was optimally produced at D-values between 0.22 and 0.26 h−1 in the presence of oxygen or paraquat, and at D-values greater than 0.17 h−1 when copper was used. On the other hand, catalase activity decreased with increasing D-values. However, the presence of copper or 100% oxygen repressed catalase activity at low D-values (D〈0.1 h−1), and decreased the rate of oxygen uptake at all D-values tested. The presence of paraquat affected the rate of oxygen uptake only at high D-values (D〉0.22 h−1). We also studied the effect of oxygen concentration on the biosynthesis of SOD and catalase at D=0.1 h−1. The data clearly show that synthesis of SOD and catalase, though correlated with changes in oxygen tension, are independent of one another.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00253027
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