Product deactivation in recombinant Streptomyces.
The production of tyrosinase by Streptomyces antibioticus (p1J7O2) was investigated as a model system for recombinant protein production by Streptomyces. Product deactivation was found to have a severe effect on the levels of tyrosinase obtained. Tyrosinase deactivation was detected during all phases of batch cultures, with higher specific deactivation rates observed during the stationary phase. The specific deactivation rate exhibited an Arrhenius dependence on temperature, with approximately a twofold increase in the deactivation rate between 25 degrees C and 30 degrees C. The effect of deactivation on the determination of tyrosinase production kinetics is discussed. A strategy was implemented to increase tyrosinase productivity by enriching the growth medium and reducing the culture temperature during the period of maximum tyrosinase production. This strategy resulted in a shorter culture time and a 2.5-fold increase in tyrosinase activity compared to a culture grown at 25 degrees C using a standard growth medium.
Gardner
A R
AR
Chemical and Biochemical Engineering Program, University of Maryland Baltimore County, Baltimore, Maryland 21228, USA.
Cadman
T W
TW