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RESULTS OF A LONG DURATION (72-DAY) SPACE FLIGHT EXPERIMENT ON MICROBIAL ANTIBIOTIC PRODUCTION.      M.R. Benoit¹, D.M. Klaus¹ and W. Li².  ¹BioServe Space Technologies, University of Colorado, Boulder, and ²Bristol-Myers Squibb Company, Wallingford, Connecticut.

   Previous findings from three earlier pilot studies conducted aboard shuttle missions STS-77, -80 and -95 indicated that microbial antibiotic specific productivity in space was increased by up to 190% relative to comparable ground controls. Absolute yields of antibiotic obtained in the reactors used for these experiments, however, were substantially lower than those obtained in shake flasks typically used in the laboratory. Therefore, in conjunction with the primary research objectives, the hardware designs used to conduct the experiments in space were concurrently evolved to increase absolute production levels and allow autonomous, long duration operation.

   An experiment was flown aboard the International Space Station (ISS) for 72 days during the 8A Increment (April 8 to June 19, 2002).  Cell cultures of Streptomyces plicatus that produce actinomycin D were grown with passive gas exchange in defined media maintained at 22° C.  New automated flight hardware designed for this experiment (MOBIAS) provided the capability to feed and remove waste from the cultures and periodically remove samples for preservation at 4° C within the same middeck locker volume.

   Preflight baseline data collection indicated that actinomycin D production in MOBIAS (in 1g) reached a level comparable to that typically achieved in laboratory shake flasks. Samples from the ISS 8A experiment are currently being analyzed for time course of absolute and specific productivity of the antibiotic as well as cell viability and spore count of the viable cultures. Computational modeling is also being pursued in an attempt to identify which specific physical factors of weightlessness might be responsible for differences observed between the flight and ground experiments.

   This work is supported by Bristol-Myers Squibb in collaboration with BioServe Space Technologies (NASA NCC8-131).

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